U.S. patent application number 14/835466 was filed with the patent office on 2015-12-17 for dampers for actuator assembly of hard disk drive.
The applicant listed for this patent is HGST Netherlands B.V.. Invention is credited to Jeffrey Kerner, Manoj B. Keshavan.
Application Number | 20150364155 14/835466 |
Document ID | / |
Family ID | 54203869 |
Filed Date | 2015-12-17 |
United States Patent
Application |
20150364155 |
Kind Code |
A1 |
Kerner; Jeffrey ; et
al. |
December 17, 2015 |
DAMPERS FOR ACTUATOR ASSEMBLY OF HARD DISK DRIVE
Abstract
An actuator assembly for a magnetic storage device includes a
top surface and a bottom surface that opposes the top surface. The
actuator assembly also includes a first constraining layer that is
secured to the top surface by a first adhesive layer. The first
adhesive layer is positioned between the top surface and the first
constraining layer. Additionally, the actuator assembly includes a
second constraining layer that is secured to the bottom surface by
a second adhesive layer. The second adhesive layer is positioned
between the bottom surface and the second constraining layer. At
least one of (i) the first constraining layer is configured
differently than the second constraining layer; and (ii) the first
adhesive layer is configured differently than the second adhesive
layer.
Inventors: |
Kerner; Jeffrey; (San Jose,
CA) ; Keshavan; Manoj B.; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HGST Netherlands B.V. |
Amsterdam |
|
NL |
|
|
Family ID: |
54203869 |
Appl. No.: |
14/835466 |
Filed: |
August 25, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14245932 |
Apr 4, 2014 |
9153261 |
|
|
14835466 |
|
|
|
|
Current U.S.
Class: |
360/97.19 ;
267/141; 428/174 |
Current CPC
Class: |
B32B 3/28 20130101; B32B
2307/51 20130101; B32B 2457/00 20130101; G11B 5/4833 20130101; B32B
2307/56 20130101; B32B 2605/12 20130101; B32B 7/12 20130101; B32B
2307/546 20130101; B32B 7/02 20130101; B32B 2255/06 20130101; Y10T
428/2495 20150115; Y10T 428/24628 20150115; G11B 5/4806 20130101;
Y10T 428/31678 20150401; G11B 19/2018 20130101; G11B 5/5565
20130101; F16F 1/3605 20130101; Y10T 428/31504 20150401; B32B 15/04
20130101 |
International
Class: |
G11B 19/20 20060101
G11B019/20; F16F 1/36 20060101 F16F001/36; B32B 7/02 20060101
B32B007/02; B32B 15/04 20060101 B32B015/04; B32B 3/28 20060101
B32B003/28; B32B 7/12 20060101 B32B007/12 |
Claims
1. An actuator assembly for a magnetic storage device, comprising:
a coil support comprising a top surface and a bottom surface
opposing the top surface; a first constraining layer secured to the
top surface by a first adhesive layer, the first adhesive layer
being positioned between the top surface and the first constraining
layer; and a second constraining layer secured to the bottom
surface by a second adhesive layer, the second adhesive layer being
positioned between the bottom surface and the second constraining
layer; wherein at least one of (i) the first constraining layer is
configured differently than the second constraining layer; and (ii)
the first adhesive layer is configured differently than the second
adhesive layer.
2. The actuator assembly of claim 1, wherein the first and second
constraining layers each comprises a rigid sheet.
3. The actuator assembly of claim 2, wherein the rigid sheet is
made from a metallic material.
4. The actuator assembly of claim 1, wherein the first constraining
layer is made from a first material and the second constraining
layer is made from a second material that is different than the
first material.
5. The actuator assembly of claim 1, wherein the first constraining
layer has a first thickness and the second constraining layer has a
second thickness that is different than the first thickness.
6. The actuator assembly of claim 1, wherein the first constraining
layer has a first shape and the second constraining layer has a
second shape that is different than the first shape.
7. The actuator assembly of claim 1, wherein the first and second
adhesive layers each is made from a visco-elastic adhesive.
8. The actuator assembly of claim 1, wherein the first and second
adhesive layers have a lower stiffness than the first and second
constraining layers, respectively.
9. The actuator assembly of claim 1, wherein the first adhesive
layer is made from a first adhesive and the second adhesive layer
is made from a second adhesive that is different than the first
adhesive.
10. The actuator assembly of claim 9, wherein the first adhesive
has different vibration damping characteristics than the second
adhesive.
11. The actuator assembly of claim 9, wherein the first adhesive
dampens vibrations more efficiently at higher temperatures than at
lower temperatures, and wherein the second adhesive dampens
vibrations more efficiently at lower temperatures than at higher
temperatures.
12. The actuator assembly of claim 1, wherein the first adhesive
layer has a first thickness and the second adhesive layer has a
second thickness that is different than the first thickness.
13. The actuator assembly of claim 1, wherein the first adhesive
layer has a first shape and the second adhesive layer has a second
shape that is different than the first shape.
14. The actuator assembly of claim 1, wherein the first
constraining layer is configured differently than the second
constraining layer, and the first adhesive layer is configured
differently than the second adhesive layer.
15. A magnetic storage device, comprising: at least one magnetic
disk; a coil support rotatably movable relative to the at least one
magnetic disk, the coil support comprising a first surface and a
second surface opposing the first surface; a first vibration damper
secured to the first surface, the first vibration damper comprising
a first constraining layer and a first adhesive layer positioned
between the first surface and the first constraining layer; and a
second vibration damper secured to the second surface, the second
vibration damper comprising a second constraining layer and a
second adhesive layer positioned between the second surface and the
second constraining layer; wherein the first vibration damper is
configured differently than the second vibration damper.
16. The magnetic storage device of claim 15, wherein the first
adhesive layer is made from a first adhesive, the second adhesive
layer is made from a second adhesive, and the first adhesive has
different vibration damping characteristics than the second
adhesive.
17. The magnetic storage device of claim 15, wherein the first
adhesive layer is made from a first adhesive, the second adhesive
layer is made from a second adhesive, the first adhesive dampens
vibrations more efficiently at higher temperatures than at lower
temperatures, and the second adhesive dampens vibrations more
efficiently at lower temperatures than at higher temperatures.
18. An apparatus for damping vibrations in an actuator assembly for
a magnetic storage device, the actuator assembly comprising a coil
support comprising a top surface and a bottom surface opposing the
top surface, the apparatus comprising: a first rigid sheet secured
to the top surface by a first visco-elastic adhesive, the first
visco-elastic adhesive being positioned between the top surface and
the first rigid sheet; and a second rigid sheet secured to the
bottom surface by a second visco-elastic adhesive, the second
visco-elastic adhesive being positioned between the bottom surface
and the second rigid sheet; wherein at least one of (i) the first
rigid sheet is configured differently than the second rigid sheet;
and (ii) the first visco-elastic adhesive is configured differently
than the second visco-elastic adhesive.
19. The apparatus of claim 18, wherein the first visco-elastic
adhesive has different vibration damping characteristics than the
second visco-elastic adhesive.
20. The apparatus of claim 18, wherein the first visco-elastic
adhesive dampens vibrations more efficiently at higher temperatures
than at lower temperatures, and wherein the second visco-elastic
adhesive dampens vibrations more efficiently at lower temperatures
than at higher temperatures.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/245,932, filed Apr. 4, 2014, which is incorporated
herein by reference.
FIELD
[0002] This disclosure relates generally to electronic information
storage devices, and more particularly to reducing vibrations of
components of information storage devices.
BACKGROUND
[0003] Hard disk drives ("HDDs") are widely used to store digital
data or electronic information for enterprise data processing
systems, computer workstations, portable computing devices, digital
audio players, digital video players, and the like. Generally, HDDs
store data on a disk with a layer of magnetic material. A
transducer head, e.g., read-write head, includes a writing
component that magnetically polarizes areas or bits of the magnetic
material with one or two polarities to encode either binary zeros
or ones. Thus, data is recorded as magnetically encoded areas or
bits of magnetic polarity. The direction of the magnetization
points in different directions, which can be referred to as a
positive state and a negative state. Each bit can store information
(generally binary information in the form of either a 1 or a 0)
according to the magnetic polarization state of the bit. Typically,
bits are arranged along respective radially-adjacent (e.g.,
concentric) annular tracks of a disk. A single disk can include
space for millions of tracks each with millions of bits. A
transducer head also includes a reading component that detects the
magnetic polarity of each bit or area and generates an electrical
signal that approximates the magnetic polarity. The signal is
processed to recover the binary data recorded on the magnetic
material.
[0004] The disks of an HDD rotate as transducer heads hover over
the respective disks to read data from and write data to the disks.
Rotation of the disks is driven by a spindle motor that is
rotatably coupled to the disks via a central spindle. The position
of the transducer heads relative to the disks, and the location on
the disks from which data is read or to which data is written, is
controlled via actuation of an actuator. The actuator controls the
movement of the plurality of armatures each securing a respective
one of the transducer heads. As the disks rotate, the actuator
actuates to rotate the armatures and move the transducer heads
radially inwardly or outwardly over the disks.
[0005] The dynamic performance of an HDD is a major mechanical
factor for achieving higher data capacity as well as for
manipulating the data faster. The quantity of data tracks recorded
on the disk surface is determined partly by how well the transducer
heads and a desired data track can be positioned relative to each
other and made to follow each other in a stable and controlled
manner. There are many factors that can influence the ability of an
HDD to perform the function of positioning the transducer heads and
following the data track with the heads. One such factor is
undesirable motions that can come about through unwanted vibrations
of components of the HDD.
SUMMARY
[0006] A need exists for an apparatus and system for reducing the
vibration of the components of an HDD that overcomes the
shortcomings of conventional HDDs. The subject matter of the
present application has been developed in response to the present
state of HDD art, and in particular, in response to problems and
needs in the art that have not yet been fully solved by currently
available HDDs.
[0007] According to one embodiment, an actuator assembly for a
magnetic storage device includes a top surface and a bottom surface
that opposes the top surface. The actuator assembly also includes a
first constraining layer that is secured to the top surface by a
first adhesive layer. The first adhesive layer is positioned
between the top surface and the first constraining layer.
Additionally, the actuator assembly includes a second constraining
layer that is secured to the bottom surface by a second adhesive
layer. The second adhesive layer is positioned between the bottom
surface and the second constraining layer. At least one of (i) the
first constraining layer is configured differently than the second
constraining layer; and (ii) the first adhesive layer is configured
differently than the second adhesive layer.
[0008] In some implementations of the actuator assembly, the first
and second constraining layers each includes a rigid sheet. The
rigid sheet can be made from a metallic material.
[0009] According to certain implementations of the actuator
assembly, the first constraining layer is configured differently
than the second constraining layer. The first constraining layer
can be made from a first material and the second constraining layer
can be made from a second material that is different than the first
material. The first constraining layer can have a first thickness
and the second constraining layer can have a second thickness that
is different than the first thickness. The first constraining layer
can have a first shape and the second constraining layer can have a
second shape that is different than the first shape. According to
one implementation, the first and second adhesive layers are
configured the same.
[0010] In certain implementations of the actuator assembly, the
first and second adhesive layers each is made from a visco-elastic
adhesive. The first and second adhesive layers can have a lower
stiffness than the first and second constraining layers,
respectively, in some implementations.
[0011] According to yet some implementations of the actuator
assembly, the first adhesive layer is configured differently than
the second adhesive layer. The first adhesive layer can be made
from a first adhesive and the second adhesive layer can be made
from a second adhesive that is different than the first adhesive.
The first adhesive layer can have a first thickness and the second
adhesive layer can have a second thickness that is different than
the first thickness. The first adhesive layer can have a first
shape and the second adhesive layer can have a second shape that is
different than the first shape. The first and second constraining
layers can be configured the same.
[0012] In some implementations of the actuator assembly, the first
constraining layer is configured differently than the second
constraining layer, and the first adhesive layer is configured
differently than the second adhesive layer.
[0013] According to certain implementations, the actuator assembly
can also include at least one armature that supports a read-write
head. The top surface is a top surface of the at least one armature
and the bottom surface is a bottom surface of the at least one
armature.
[0014] The actuator assembly can include a coil support in some
implementations. In such implementations, the top surface can be a
top surface of the coil support and the bottom surface can be a
bottom surface of the coil support.
[0015] In yet another embodiment, a magnetic storage device
includes at least one magnetic disk and at least one armature that
is rotatably movable relative to the at least one magnetic disk.
The at least one armature includes a first surface and a second
surface that opposes the first surface. The magnetic storage device
also includes a first vibration damper that is secured to the first
surface. The first vibration damper includes a first constraining
layer and a first adhesive layer that is positioned between the
first surface and the first constraining layer. The magnetic
storage device additionally includes a second vibration damper that
is secured to the second surface. The second vibration damper
includes a second constraining layer and a second adhesive layer
that is positioned between the second surface and the second
constraining layer. The first vibration damper is configured
differently than the second vibration damper.
[0016] According to another embodiment, an apparatus for damping
vibrations in an actuator assembly for a magnetic storage device is
described. The actuator assembly includes a top surface and a
bottom surface that opposes the top surface. The apparatus includes
a first rigid sheet that is secured to the top surface by a first
visco-elastic adhesive. The first visco-elastic adhesive is
positioned between the top surface and the first rigid sheet. The
apparatus also includes a second rigid sheet that is secured to the
bottom surface by a second visco-elastic adhesive. The second
visco-elastic adhesive is positioned between the bottom surface and
the second rigid sheet. The first rigid sheet is configured
differently than the second rigid sheet, and the first
visco-elastic adhesive is configured differently than the second
visco-elastic adhesive.
[0017] Reference throughout this specification to features,
advantages, or similar language does not imply that all of the
features and advantages that may be realized with the present
disclosure should be or are in any single embodiment. Rather,
language referring to the features and advantages is understood to
mean that a specific feature, advantage, or characteristic
described in connection with an embodiment is included in at least
one embodiment of the subject matter disclosed herein. Thus,
discussion of the features and advantages, and similar language,
throughout this specification may, but do not necessarily, refer to
the same embodiment.
[0018] The described features, structures, advantages, and/or
characteristics of the subject matter of the present disclosure may
be combined in any suitable manner in one or more embodiments
and/or implementations. In the following description, numerous
specific details are provided to impart a thorough understanding of
embodiments of the subject matter of the present disclosure. One
skilled in the relevant art will recognize that the subject matter
of the present disclosure may be practiced without one or more of
the specific features, details, components, materials, and/or
methods of a particular embodiment or implementation. In other
instances, additional features and advantages may be recognized in
certain embodiments and/or implementations that may not be present
in all embodiments or implementations. Further, in some instances,
well-known structures, materials, or operations are not shown or
described in detail to avoid obscuring aspects of the subject
matter of the present disclosure. The features and advantages of
the subject matter of the present disclosure will become more fully
apparent from the following description and appended claims, or may
be learned by the practice of the subject matter as set forth
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order that the advantages of the disclosure will be
readily understood, a more particular description of the disclosure
briefly described above will be rendered by reference to specific
embodiments that are illustrated in the appended drawings.
Understanding that these drawings depict only typical embodiments
of the disclosure and are not therefore to be considered to be
limiting of its scope, the subject matter of the present
application will be described and explained with additional
specificity and detail through the use of the accompanying
drawings, in which:
[0020] FIG. 1 is a perspective view of a magnetic storage device
with vibration dampers according to one embodiment;
[0021] FIG. 2 is a top perspective view of an actuator assembly,
with vibration dampers, of a magnetic storage device according to
one embodiment;
[0022] FIG. 3 is a bottom perspective view of an actuator assembly,
with vibration dampers, of a magnetic storage device according to
one embodiment; and
[0023] FIG. 4 is a cross-sectional side view of a component, with
vibration dampers, of a magnetic storage device according to
another embodiment.
DETAILED DESCRIPTION
[0024] Referring to FIG. 1, a magnetic storage device 100,
according to one embodiment, is depicted as a hard disk drive
(HDD). The HDD can be configured similarly to a conventional HDD as
depicted generally in the illustrated embodiments. Alternatively,
the HDD can be configured similarly to a so-called hybrid HDD that
includes a combination of flash media and magnetic disk media. In
yet other embodiments, the magnetic storage device 100 can be
another type of magnetic storage device, or yet another type of
data storage device, such as an optical recording device.
Basically, the HDD 100 includes an actuator assembly 140, one or
more disks 115, a spindle 121 driven by a spindle motor, and a base
130. The base 130 forms part of a housing, shown with a cover
removed, that contains internal components of the HDD within the
housing.
[0025] The actuator assembly 140 includes a plurality of armatures
105 coupled to a base 155, transducer heads 110, an actuator 118, a
yoke assembly 142 (see, e.g., FIG. 2), and a spindle 125. Each
transducer head 110 is secured to an end portion 107 of a
respective armature 105 (a second transducer head attached to each
armature is not shown). Although the HDD 100 is shown having four
armatures 105, one transducer head 110 per armature, four disks
115, and one yoke assembly, any number of armatures, heads, disks,
and yoke assemblies may be employed.
[0026] The armatures 105 extend parallel to each other away from
the base 155 to cantilevered end portions 107. Each armature 105 is
a relatively thin plate-like element, which has a width that, in
certain implementations, decreases in a direction extending away
from the base 155. The armatures 105 are spaced apart vertically
(e.g., top-to-bottom direction) such that a disk 115 can be
positioned between adjacent armatures. In some instances, the
armatures 105 are spaced an equal distance apart from each other.
Each armature 105 defines a top surface 157 and a bottom surface
161 that opposes the top surface. In certain implementations, the
top and bottom surfaces 157, 161 oppose each other when they define
generally opposite sides of the corresponding armature 105.
According to certain implementations, the top and bottom surfaces
157, 161 oppose each other when the top and bottom surfaces are
parallel to each other, and spaced apart from each other by a
thickness of the corresponding armature 105. The opposing surfaces
can, but need not, be flat. The armatures 105 may include apertures
for attachment of other components or for weight saving purposes.
The apertures can extend from the top surface 157 to the bottom
surface 161 of each armature. In some embodiments, the armatures
105 are integrally formed with the base 155 such that they form a
monolithic one-piece construction with the base. In other
embodiments, the armatures 105 are formed separate from the base
155 and coupled to the base in a separate processing step via any
of various coupling techniques.
[0027] The yoke assembly 142 includes coil supports 158 and a coil
171 coupled to the coil supports. The coil supports 158 can be arms
that are coupled to and extend away from the base 155. The coil
supports 158 are spaced-apart to support the coil 171 between the
coil supports. Although the coil supports 158 extend only partially
around a periphery of the coil 171, in some implementations, the
coil supports 158 may extend entirely around a periphery of the
coil. Like the armatures 105, each coil support 158 defines a top
surface 159 and a bottom surface 163 that opposes the top surface.
In some embodiments, the coil supports 158 are integrally formed
with the base 155 such that they form a monolithic one-piece
construction with the base. In other embodiments, the coil supports
158 are formed separate from the base 155 and coupled to the base
in a separate processing step via any of various coupling
techniques.
[0028] The coil 171 includes an electrically-conductive wire
wrapped about itself in a coiled configuration. The actuator 118
interacts with the coil 171 to rotate the coil, as well as the base
155 and armatures 105, about the spindle 125. In one
implementation, the actuator 118 passes current through the coil
171, which results in a torque applied to the actuator. The base
155 includes an aperture 127 that receives the spindle 125. The
aperture 127 is configured to retain the spindle 125 and allow
rotation of the base 155 relative to the spindle.
[0029] The armatures 105, base 155, and coil supports 158 are made
from a substantially rigid material. For example, in one
embodiment, one or more of the armatures 105, base 155, and coil
supports 158 is made from a metal, such as aluminum. In other
embodiments, one or more of the armatures 105, base 155, and coil
supports 158 is made from another substantially rigid material,
such as ceramic, composite, polymer, and the like.
[0030] The spindle 121 is operably connected to the base 130 via
the spindle motor, which is coupled to the base. The spindle 121 is
co-rotatably coupled to the spindle motor such that the spindle
motor rotatably drives the spindle. Accordingly, the spindle 121
can be considered to be part of or integral with the spindle motor.
The disks 115 are operably connected to the spindle 121 via
respective hubs 120 fixedly secured to respective disks and
co-rotatably coupled to the spindle. In this manner, the spindle
121 defines a central axis of each disk 115. As the spindle 121
rotates, the disks 115 correspondingly rotate as indicated by
directional arrow 190. Accordingly, the spindle motor can be
operatively controlled to rotate the disks 115 a controlled amount
and at a controlled rate. The disks 115 can include magnetic
recording media organized into a plurality of tracks that store
data.
[0031] As the disks 115 rotate, the actuator 118 positions the
armatures 105 and the heads 110 connected to each armature, such
that the heads are positioned over a specified radial area of the
disks for read or write operations. In an idle mode, the actuator
118 is controlled to position the armatures 105 radially outwardly
such that each head is parked or unloaded onto a ramp support 117
secured to the base.
[0032] The HDD 100 may also include an electrical hardware board
mounted to the base 130. In this manner, the electrical hardware
board is on-board or contained within the HDD 100, as opposed to
forming part of an electrical device external to or separate from
the HDD. Generally, the electrical hardware board includes hardware
and/or circuitry used to control operation of the various
components of the HDD 100. The electrical hardware board may
include a printed circuit board on or in which the hardware and/or
circuitry is mounted.
[0033] To reduce vibrations in the actuator assembly 140, the
actuator assembly includes a plurality of vibration dampers or
damper sets. Each vibration damper set includes two or more
vibration dampers. For example, referring to FIG. 2, a plurality of
top vibration dampers 150 are shown secured to the top surfaces 157
of respective armatures 105. In the illustrated embodiment, the top
vibration dampers 150 are positioned on the top surfaces 157
between the aperture 127 of the base 155 and the end portions 107
of the armatures 105. Similarly, as shown in FIG. 3, a plurality of
bottom vibration dampers 152 are secured to the bottom surfaces 161
of respective armatures 105. The top and bottom vibration dampers
150, 152 of each armature 105 can be defined collectively as a
vibration damper set or pair.
[0034] Moreover, the top and bottom vibration dampers 150, 152 of
each vibration damper set are configured differently. In other
words, the top vibration damper 150 secured to a given armature 105
has a first configuration and the bottom vibration damper 152
secured to the same armature has a second configuration that is
different than the first configuration. In some implementations,
the configuration of each vibration damper can be defined as at
least one of a material composition, thickness, and shape of the
vibration damper. Accordingly, the configuration of a top vibration
damper is different than the configuration of a bottom vibration
damper when one or more of the material composition, thickness, and
shape of the top vibration damper is different than the material
composition, thickness, and shape, respectively, of the bottom
vibration damper. In other implementations, the configuration of
each vibration damper can be defined according to other
characteristics as desired. In some embodiments, the configuration
of one damper is considered different than another damper when the
configurations vary substantially. According to some
implementations, two configurations vary substantially when a
differing characteristic varies by more than a certain percentage
threshold. In one implementation, the percentage threshold can be
about 5%. In yet some implementations, the configuration of one
damper is considered different than another damper when the
configurations vary more than nominally.
[0035] Each damper includes a constraining layer and an adhesive
layer. Generally, the constraining or stiffener layer is secured to
a surface of a component of a storage device by the adhesive layer.
The adhesive layer is applied directly onto the surface of the
component. The constraining layer is coupled directly onto the
adhesive layer, such that the adhesive layer is positioned between
the surface of the component and the constraining layer.
[0036] In one exemplary embodiment shown in FIG. 4, the top
vibration damper 150 includes a constraining layer 154 and an
adhesive layer 170. The constraining layer 154 is secured to the
top surface 157 of the armature 105 of the HDD 100. The adhesive
layer 170 is applied directly onto the top surface 157 of the
armature 105. The constraining layer 154 is coupled directly onto
the adhesive layer 170, such that the adhesive layer is positioned
between the top surface 157 of the armature 105 and the
constraining layer. The bottom vibration damper 152 also includes a
constraining layer 156 and an adhesive layer 172. The constraining
layer 156 is secured to the bottom surface 161 of the armature 105
of the HDD 100. The adhesive layer 172 is applied directly onto the
bottom surface 161 of the armature 105. The constraining layer 156
is coupled directly onto the adhesive layer 172, such that the
adhesive layer is positioned between the bottom surface 161 of the
armature 105 and the constraining layer. As described above, the
top and bottom vibration dampers 150, 152 can be a set of vibration
dampers with the constraining layer 154 and adhesive layer 170 of
the top vibration damper 150 being first or top constraining and
adhesive layers, and the constraining layer 156 and adhesive layer
172 of the bottom vibration damper 152 being second or bottom
constraining and adhesive layers.
[0037] The adhesive layers 170, 172 of the top and bottom vibration
dampers 150, 152 are made from an adhesive material with vibration
damping properties. Accordingly, adhesive material of the adhesive
layers 170, 172 provides both adhesion properties for adhering to
the top and bottom surfaces 157, 161, respectively, and to the
constraining layers 154, 156, respectively, and vibration damping
properties for damping vibrations in the armature 105. Generally,
the adhesive material has sufficient adhesion properties to
adequately secure the constraining layers 154, 156 to the top and
bottom surfaces 157, 161, respectively. In some embodiments, the
constraining layers 154, 156 are secured to the top and bottom
surfaces 157, 161, respectively, solely by the respective adhesive
layers 170, 172. In other words, according to such embodiments, no
fasteners or other securing means, other than the adhesive layers
170, 172, are used to secure the constraining layers 154, 156 to
the top and bottom surfaces 157, 161. In these embodiments, the
adhesive layers 170, 172 are positioned directly between the
constraining layers 154, 156, respectively, and the top and bottom
surfaces 157, 161, respectively. In some implementations, one or
both the adhesive layers 170, 172 can be made from multiple stacked
adhesive layers of the same or different configuration.
[0038] The adhesive materials of the adhesive layers 170, 172 can
be any of various adhesives having desired damping properties. In
some implementations, the adhesive materials include a
visco-elastic adhesive (e.g., a material that exhibits both viscous
and elastic characteristics when undergoing deformation). The
visco-elastic material can be any of various visco-elastic
materials, such as visco-elastic damping polymers (e.g., Damping
Polymer 242 manufactured by 3M.TM.), and the like. Often, the
vibration damping characteristics of the adhesive materials of the
adhesive layers 170, 172 can vary based on the temperature of the
adhesive materials, and other factors. For example, some adhesives
may dampen vibrations more efficiently at higher temperatures than
lower temperatures, and other adhesives may dampen vibrations more
efficiently at lower temperatures than higher temperatures.
Although both the adhesive layers 170, 172 are made from an
adhesive with vibration damping properties, in some
implementations, the top adhesive layer 170 is made from a first
adhesive and the bottom adhesive layer 172 is made from a second
adhesive that is different than the first adhesive. For example,
the first adhesive can have a chemical composition that is
different than the second adhesive. In one example, the first
adhesive can have different adhesion properties than the second
adhesive. In yet another example, the first adhesive can have
different damping properties than the second adhesive. In any of
the above examples, the top adhesive layer 170 is considered to be
configured differently than the bottom adhesive layer 172. However,
in alternative embodiments, the first and second adhesives can be
the same.
[0039] In addition to the type of adhesive, the damping
characteristics of the adhesive layers 170, 172 may depend on the
thickness of the layers. The adhesive layers 170, 172 can have any
of various thicknesses based on desired damping characteristics.
For example, in some specific implementations, the thickness of
each adhesive layer 170, 172 can vary between about 0.015 mm and
about 0.1 mm. According to some implementations, the first and
second adhesive layers 170, 172 have different thicknesses. As
shown in FIG. 4, the first adhesive layer 170 may be thicker than
the second adhesive layer 172. However, in other implementations,
the second adhesive layer 172 may be thicker than the first
adhesive layer 170. In some embodiments, the first and second
adhesive layers 170, 172 can have the same thickness.
[0040] The damping characteristics of the adhesive layers 170, 172
may also depend on the shape of the layers. As defined herein,
according to some implementations, the shape of an adhesive layer
is the shape of the footprint of the adhesive layer, or the shape
of the adhesive layer in plan view. Additionally, in certain
implementations, the shape of an adhesive layer can be the
cross-sectional shape of the adhesive layer taken along a plane
parallel to the surface upon which the adhesive is secured. Because
vibrations behave differently when interacting with differently
sized and shaped boundaries of a layer, the shape of or features
along the outer peripheries of the adhesive layers affect the
vibration attenuating or vibration damping properties of the
layers. According to some implementations, the first and second
adhesive layers 170, 172 of a given set have different shapes. As
shown in FIG. 2, for example, the top adhesive layer 170 of the
damper set on an adjacent armature 105 below the topmost armature
105 has a shape that is different than the shapes of the other top
adhesive layers 170, as well as the shape of the bottom adhesive
layer 172 of the same set (see, e.g., FIG. 3). Alternatively, in
some embodiments, the first and second adhesive layers 170, 172 can
have the same shapes.
[0041] The constraining layers 154, 156 of the top and bottom
vibration dampers 150, 152 are made from materials more rigid or
stiff than the adhesive materials of the adhesive layers 170, 172.
Because the constraining layers 154, 156 are stiffer than the
respective adhesive layers 170, 172, the constraining layers 154,
156 constrain (e.g., limit) the deformation of the adhesive layers
170, 172 as the adhesive layers undergo shear deformation when the
armature 105 vibrates during operation of the HDD 100. In some
implementations, one or both the constraining layers 154, 156 can
be made from multiple stacked constraining layers of the same or
different configuration.
[0042] The materials of the constraining layers 154, 156 can be any
of various materials having desired constraining properties. In
some implementations, the constraining layers 154, 156 are made
from a non-magnetic metal, such as stainless steel, aluminum, and
the like, or a non-metal, such as plastic, composite, ceramic, and
the like. Often, the constraining properties (e.g., stiffness) of
the materials of the constraining layers 154, 156 can vary based on
the temperature of the adhesive materials, and other factors. For
example, some constraining materials may be less stiff at higher
temperatures than lower temperatures. Although both the
constraining layers 154, 156 are made from a relatively stiff,
non-magnetic material, in some implementations, the top
constraining layer 154 is made from a first constraining material
and the bottom constraining layer 156 is made from a second
constraining material that is different than the first constraining
material. For example, the first constraining material can have a
chemical composition that is different than the second constraining
material. In one example, the first constraining material can have
different stiffness properties than the second constraining
material. In any of the above examples where the constraining
materials are different, the top constraining layer 154 is
considered to be configured differently than the bottom
constraining layer 156. However, in alternative embodiments, the
first and second constraining materials can be the same.
[0043] In addition to the type of material, the constraining
characteristics of the constraining layers 154, 156 may depend on
the thickness of the layers. The constraining layers 154, 156 can
have any of various thicknesses based on desired constraining or
stiffness characteristics. For example, in some specific
implementations, the thickness of each constraining layer 154, 156
can vary between about 0.015 mm and about 0.1 mm. According to some
implementations, the first and second constraining layers 154, 156
have different thicknesses. As shown in FIG. 4, the first
constraining layer 154 may be thicker than the second constraining
layer 156. However, in other implementations, the second
constraining layer 156 may be thicker than the first constraining
layer 154. In some embodiments, the first and second constraining
layers 154, 156 can have the same thickness.
[0044] The constraining characteristics of the constraining layers
154, 156 may also depend on the shape of the layers. As defined
herein, according to some implementations, the shape of a
constraining layer is the shape of the footprint of the
constraining layer, or the shape of the constraining layer in plan
view. Additionally, in certain implementations, the shape of a
constraining layer can be the cross-sectional shape of the
constraining layer taken along a plane parallel to the surface upon
which the adhesive layer is secured. Because the stiffness of an
object may vary according to differently sized and shaped
boundaries of the object, the shape of or features along the outer
peripheries of the constraining layers affect the constraining
properties (e.g., stiffness) of the layers. According to some
implementations, the first and second constraining layers 154, 156
of a given set have different shapes. As shown in FIG. 2, for
example, the top constraining layer 154 of the damper set on an
adjacent armature 105 below the topmost armature 105 has a shape
that is different than the shapes of the other top constraining
layers 154, as well as the shape of the bottom constraining layer
156 of the same set (see, e.g., FIG. 3). Alternatively, in some
embodiments, the first and second constraining layers 154, 156 can
have the same shapes.
[0045] As defined herein, the configuration of a first vibration
damper is different than a second vibration damper if at least one
of (i) the configuration of the adhesive layer of the first
vibration damper is different than the configuration of the
adhesive layer of the second vibration damper; and (ii) the
configuration of the constraining layer of the first vibration
damper is different than the configuration of the constraining
layer of the second vibration damper. In one implementation, only
the configuration of the adhesive layer of the first vibration
damper is different than the configuration of the adhesive layer of
the second vibration damper. In another implementation, only the
configuration of the constraining layer of the first vibration
damper is different than the configuration of the constraining
layer of the second vibration damper. According to yet another
implementation, both the configuration of the adhesive layer of the
first vibration damper is different than the configuration of the
adhesive layer of the second vibration damper, and the
configuration of the constraining layer of the first vibration
damper is different than the configuration of the constraining
layer of the second vibration damper.
[0046] The configuration of the adhesive layer of a first vibration
damper is different than the configuration of the adhesive layer of
a second vibration damper if the adhesive layer of the first
vibration damper has a different material composition, thickness,
shape and/or other characteristic than the adhesive layer of the
second vibration damper. Similarly, the configuration of the
constraining layer of a first vibration damper is different than
the configuration of the constraining layer of a second vibration
damper if the constraining layer of the first vibration damper has
a different material composition, thickness, shape and/or other
characteristic than the constraining layer of the second vibration
damper.
[0047] As mentioned above, vibration dampers with different
configurations may produce different vibration damping
characteristics. Often, the vibration damping characteristics of
vibration dampers are dependent on external factors, such as the
operating temperature of the layers of the vibration dampers. For
example, for a given temperature, one vibration damper may produce
certain damping characteristics that are different than the damping
characteristics produced by a differently configured vibration
damper at the same temperature. In contrast, one vibration damper
at a given temperature (or temperature range) may produce the same
damping characteristics as a differently configured vibration
damper at a different temperature (or temperature range).
Accordingly, in some implementations, to ensure similar damping
characteristics across a broader temperature range, a vibration
damper set with differently configured vibration dampers can be
applied to an armature (or other component) in an opposing manner
as described above. Referring to FIG. 4 above, in one specific
implementation, the top vibration damper 150 can be configured to
achieve a certain vibration reduction factor at a relatively higher
range of temperatures, and the bottom vibration damper 152 can be
configured to achieve the same vibration reduction factor at a
relatively lower range of temperatures. The higher and lower range
of temperatures can be contiguous in some embodiments.
[0048] Although the above described embodiments refer to the
placement of differently configured vibration dampers on opposing
surfaces of armatures of an actuator assembly of an HDD, in other
embodiments, the differently configured vibration dampers can be
placed on opposing surfaces of other moving (or non-moving)
components of an HDD, data storage device, or other electronic
device to achieve similar results without departing from the
essence of the present disclosure. For example, as shown in FIGS.
2-4, top vibration dampers 160 are shown secured to top surfaces
159 of respective coil supports 158. Similarly, bottom vibration
dampers 162 are secured to the bottom surfaces 163 of respective
coil supports 158. The top and bottom vibration dampers 160, 162 of
each coil support 158 can be defined collectively as a vibration
damper set or pair. The features of the top and bottom vibration
dampers 160, 162 are similar to analogous features of the top and
bottom vibrations dampers 150, 152. This fact is evidenced by the
incorporation of the reference numbers for the analogous features
of the coil supports 158 and top and bottom vibration dampers 160,
162 into FIG. 4.
[0049] Although some of the above embodiments are described and
shown to place differently configured dampers on opposing or
opposite surfaces of a component, in some implementations it may be
desirable to place differently configured dampers on adjacent or
orthogonal surfaces, such as a top surface and a perpendicular
side/edge surface.
[0050] Reference throughout this specification to "one embodiment,"
"an embodiment," or similar language means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
present disclosure. Thus, appearances of the phrases "in one
embodiment," "in an embodiment," and similar language throughout
this specification may, but do not necessarily, all refer to the
same embodiment.
[0051] In the above description, certain terms may be used such as
"top," "bottom," "up," "down," "upper," "lower," "horizontal,"
"vertical," "left," "right," and the like. These terms are used,
where applicable, to provide some clarity of description when
dealing with relative relationships. But, these terms are not
intended to imply absolute relationships, positions, and/or
orientations. For example, with respect to an object, a "top"
surface can become a "bottom" surface simply by turning the object
over. Nevertheless, it is still the same object. Further, the terms
"including," "comprising," "having," and variations thereof mean
"including but not limited to" unless expressly specified
otherwise. An enumerated listing of items does not imply that any
or all of the items are mutually exclusive and/or mutually
inclusive, unless expressly specified otherwise. The terms "a,"
"an," and "the" also refer to "one or more" unless expressly
specified otherwise. Further, the term "plurality" can be defined
as "at least two."
[0052] Additionally, instances in this specification where one
element is "coupled" to another element can include direct and
indirect coupling. Direct coupling can be defined as one element
coupled to and in some contact with another element. Indirect
coupling can be defined as coupling between two elements not in
direct contact with each other, but having one or more additional
elements between the coupled elements. Also, securing one element
to another element can include direct and indirect securing.
Additionally, as used herein, "adjacent" does not necessarily
denote contact (i.e., one element can be adjacent to another
without being in contact with the other).
[0053] As used herein, the phrase "at least one of", when used with
a list of items, means different combinations of one or more of the
listed items may be used and only one of the items in the list may
be needed. The item may be a particular object, thing, or category.
In other words, "at least one of" means any combination of items or
number of items may be used from the list, but not all of the items
in the list may be required. For example, "at least one of item A,
item B, and item C" may mean item A; item A and item B; item B;
item A, item B, and item C; or item B and item C. In some cases,
"at least one of item A, item B, and item C" may mean, for example,
without limitation, two of item A, one of item B, and ten of item
C; four of item B and seven of item C; or some other suitable
combination.
[0054] The subject matter of the present disclosure may be embodied
in other specific forms without departing from its spirit or
essential characteristics. The described embodiments are to be
considered in all respects only as illustrative and not
restrictive. The scope of the disclosure is, therefore, indicated
by the appended claims rather than by the foregoing description.
All changes which come within the meaning and range of equivalency
of the claims are to be embraced within their scope.
* * * * *