U.S. patent application number 15/811978 was filed with the patent office on 2019-05-16 for disk drive having multiple disks accessible by a reduced number of read/write heads.
The applicant listed for this patent is Seagate Technology LLC. Invention is credited to ChuenBuan Lee, Xiong Liu, Hao Sun.
Application Number | 20190147909 15/811978 |
Document ID | / |
Family ID | 66175029 |
Filed Date | 2019-05-16 |
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United States Patent
Application |
20190147909 |
Kind Code |
A1 |
Sun; Hao ; et al. |
May 16, 2019 |
DISK DRIVE HAVING MULTIPLE DISKS ACCESSIBLE BY A REDUCED NUMBER OF
READ/WRITE HEADS
Abstract
A disk drive including multiple magnetic recording disks and at
least one read/write head, wherein the disk drive includes a
rotatable center block having a vertical axis and a mounting
member, a first motor attached to the center block for rotating the
center block about the vertical axis, a vertical threaded rod
positioned in the mounting member, a second motor moveable along
the vertical threaded rod, at least one head suspension arm
extending outwardly from the second motor, and at least one
read/write head mounted to a distal end of one of the arms. The
disk drive further includes multiple disks in a stack, wherein at
least one of the arms is vertically moveable along the vertical
threaded rod by the second motor to position the at least one
read/write head in a position to access data on one of the disk
surfaces of the plurality of disks.
Inventors: |
Sun; Hao; (Singapore,
SG) ; Lee; ChuenBuan; (Singapore, SG) ; Liu;
Xiong; (Singapore, SG) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Seagate Technology LLC |
Cupertino |
CA |
US |
|
|
Family ID: |
66175029 |
Appl. No.: |
15/811978 |
Filed: |
November 14, 2017 |
Current U.S.
Class: |
360/98.02 |
Current CPC
Class: |
G11B 5/5521 20130101;
G11B 17/021 20130101; G11B 5/54 20130101; G11B 5/4813 20130101 |
International
Class: |
G11B 5/54 20060101
G11B005/54; G11B 5/48 20060101 G11B005/48 |
Claims
1. A disk drive comprising a plurality of magnetic recording disks
and at least one read/write head for writing data to and reading
data from the disks, the disk drive comprising: a rotatable center
block comprising a vertical axis and a mounting member; a first
motor attached to the center block for rotating the center block
about the vertical axis; a first vertical threaded rod positioned
in the mounting member; a second motor moveable along the vertical
threaded rod; at least one head suspension arm extending outwardly
from the second motor; at least one read/write head mounted to a
distal end of the at least one head suspension arm; wherein the
plurality of magnetic disks are arranged in a stack, wherein each
disk of the stack comprises at least one disk surface comprising
data storage tracks; wherein the at least one arm is vertically
movable along the vertical threaded rod by the second motor to
position the at least one read/write head for accessing data on at
least one of the plurality of disks.
2. The disk drive of claim 1, wherein the second motor is a
piezoelectric motor assembly.
3. The disk drive of claim 1, wherein the mounting member comprises
an upper plate spaced from a lower plate, and wherein the vertical
threaded rod is positioned between the upper and lower plates.
4. The disk drive of claim 1, wherein the at least one head
suspension arm comprises a first head suspension arm and a second
head suspension arm extending outwardly from the second motor,
wherein the first and second head suspension arms each comprise a
read/write head at a distal end, and wherein the read/write heads
of the first and second head suspension arms are offset relative to
each other in a offset direction that is perpendicular to a
direction in which the second motor moves along the vertical
threaded rod.
5. The disk drive of claim 1, further comprising a ramp with at
least one extending ramp fin.
6. The disk drive of claim 5, wherein the number of extending ramp
fins is the same as the number of disks in the stack.
7. The disk drive of claim 5, wherein the ramp is connected to a
third motor that is vertically moveable along a second vertical
threaded rod to move the at least one head suspension arm to access
multiple disks of the stack.
8. The disk drive of claim 7, wherein the third motor is configured
for synchronized movement with the second motor.
9. The disk drive of claim 1, wherein the at least one arm is
vertically movable and repositionable along the vertical threaded
rod to position the at least one read/write head in multiple
vertical locations to access data on multiple disks.
10. The disk drive of claim 1, further comprising a fourth motor
for rotating the at least one suspension arm 180 degrees relative
to surfaces of the disks.
11. The disk drive of claim 1, wherein the number of disk surfaces
of the stack of disks is greater than the number of read/write
heads.
12. The disk drive of claim 2, wherein the piezoelectric motor
assembly further comprises a threaded member that is engageable
with the first vertical threaded rod.
13. The disk drive of claim 12, wherein the piezoelectric motor
assembly further comprises multiple plates.
14. The disk drive of claim 13, wherein at least one of the
multiple plates contacts the mounting member and prevents rotation
of the threaded member relative to the mounting member.
15. The disk drive of claim 1, wherein the mounting member
comprises a C-shaped member.
16. The disk drive of claim 1, wherein the at least one head
suspension arm is rotatable about an axis that is parallel to one
of the disk surfaces.
Description
BACKGROUND
[0001] Hard disc drive (HDD) systems typically include a stack of
data storage disks with concentric tracks containing information
and rotated by a spindle motor. Transducing heads or read/write
heads carried by a slider are used to read from and write to a data
track on the disks, with each disk surface being accessible by a
dedicated read/write head. The disks in the stack are in a fixed
position relative to one another and are not movable axially, i.e.,
in a direction parallel to the axis of rotation of the spindle
motor. Each read/write head is formed on an air-bearing slider
attached to one end of a suspension, and each suspension is
attached at its other end to a rigid arm of the actuator.
[0002] In order to access information quickly (e.g., for reading
and writing data to a disk), a typical HDD will have a read/write
head positioned adjacent to each disk surface that is available to
read or write data. In such a configuration, the cost of having a
read/write head for each disk surface is a relatively large portion
of the cost of the HDD, especially in HDDs having large numbers of
disks. In particular, each of the multiple read/write heads
requires its own physical supporting structures, cabling
connections to the HDD electronics, and the like.
[0003] FIG. 1 illustrates an exemplary configuration of a
conventional hard disk drive (HDD) system 20. The HDD system
generally includes a stack including several magnetic storage disks
22 configured to rotate about an axis 24, an actuation motor 26
(e.g., a voice coil motor), multiple actuator arms 28 and
corresponding suspension assemblies 30, each of which includes a
load beam and a slider 32 carrying a transducing or read/write head
(not visible). Each slider 32 is supported by suspension assembly
30, which in turn is supported by an actuator arm 28. Together,
each actuator arm 28, suspension assembly 30 and slider 32 form a
head stack assembly (HSA).
[0004] Actuation motor 26 is configured to pivot actuator arm 28
about an axis 34 in order to sweep suspension 30 and slider 32 in
an arc across a surface of rotating disk 22 with slider 32
"sliding" or "flying" across disk 22 on a cushion of air, often
referred to as an air bearing. The read/write head carried by
slider 32 can be positioned relative to selected concentric data
tracks 36 of disk 22 by a microactuator, not seen in FIG. 1. A
stack of co-rotating disks 22 are generally provided with pairs of
similar or identical actuator arms 28, suspension assemblies 30,
and sliders 32 that carry read/write heads for reading and writing
the top and bottom surfaces of each disk 22 in the stack. Thus, an
exemplary HDD having a 4-disk stack with eight accessible surfaces
will include actuator arms, suspension assemblies, and sliders to
support eight read/write heads.
[0005] Because there is pressure in the industry to lower the cost
per unit of data for individual HDD systems, there is an increasing
desire to eliminate components and/or provide less expensive
components for drives, while maintaining quality and accuracy.
SUMMARY
[0006] In accordance with the invention, HDD systems are provided
that are more economical for all types of data storage and
retrieval, but can be particularly beneficial for systems that
include large amounts of "cold" data that is only accessed
occasionally. Systems of the invention include at least one
read/write head that is moveable to access more than one disk
surface, wherein the system includes less read/write heads than
disk surfaces to access. That is, an exemplary system with four
disks with eight accessible disk surfaces will include less than
eight read/write heads, such as one or two read/write heads that
are moveable to access all of the disks.
[0007] Aspects of the invention described herein are directed to a
hard disk drive comprising a plurality of magnetic recording disks
and at least one read/write head for writing data to and reading
data from the disks. The disk drive includes a rotatable center
block comprising a vertical axis and a mounting member or adaptor,
a first motor attached to the center block for rotating the center
block about the vertical axis, a vertical threaded rod positioned
in the mounting member or adaptor, a second motor moveable along
the vertical threaded rod, at least one head suspension arm
extending outwardly from the second motor, and at least one
read/write head mounted to a distal end of one of the head
suspension arms. The disk drive further includes multiple disks in
a stack, wherein each disk has at least one disk surface containing
data storage tracks. At least one of the head suspension arms is
vertically moveable along the vertical threaded rod by the motor to
position at least one read/write head in a position to access data
on one of the disk surfaces of the plurality of disks.
[0008] In further accordance with aspects of the invention, the
second motor is a piezoelectric motor assembly. Additionally, the
mounting member may include an upper plate spaced from a lower
plate, and wherein the vertical threaded rod is positioned between
the upper and lower plates. The at least one head suspension arm
may comprise a first head suspension arm and a second head
suspension arm extending outwardly from the second motor, wherein
the first and second head suspension arms each comprise a
read/write head at a distal end, and wherein the read/write heads
of the first and second head suspension arms are offset relative to
each other in a offset direction that is perpendicular to a
direction in which the second motor moves along the vertical
threaded rod. The disk drive may further comprise a ramp with at
least one extending ramp fin. wherein the number of extending ramp
fins can be the same as the number of disks in the stack, and the
ramp may be connected to a third motor that is vertically moveable
along a second vertical threaded rod to move the at least one head
suspension to access multiple disks of the stack and the third
motor may be configured for synchronized movement with the second
motor.
[0009] The at least one arm may be vertically movable and
repositionable along the vertical threaded rod to position the at
least one read/write head in multiple vertical locations to access
data on multiple disks. The disk drive can further include a fourth
motor for rotating the at least one suspension arm 180 degrees
relative to surfaces of the disks. The number of disk surfaces of
the stack of disks can be greater than the number of read/write
heads.
[0010] These and various other features and advantages will be
apparent from a reading of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be further explained with
reference to the appended Figures, wherein like structure is
referred to by like numerals throughout the several views, and
wherein:
[0012] FIG. 1 is a perspective view of an prior art hard disk drive
(HDD) system;
[0013] FIG. 2 is a side view of an embodiment of a head stack
assembly, in accordance with the invention;
[0014] FIG. 3 is a top view of the embodiment of a head stack
assembly of FIG. 2;
[0015] FIG. 4 is an enlarged top cross-sectional view of a portion
of an embodiment of a head stack assembly, in accordance with the
invention;
[0016] FIG. 5 is another enlarged top cross-sectional view of a
portion of an embodiment of a head stack assembly, in accordance
with the invention;
[0017] FIG. 6 is a side view of an embodiment of a head stack
assembly in accordance with the invention;
[0018] FIG. 7 is a top view of the embodiment of a head stack
assembly of FIG. 6;
[0019] FIG. 8 is an enlarged top cross-sectional view of a portion
of an embodiment of a head stack assembly in accordance with the
invention;
[0020] FIG. 9 is another enlarged top cross-sectional view of a
portion of an embodiment of a head stack assembly in accordance
with the invention;
[0021] FIGS. 10A-10F are sequential top views of a portion of a
hard drive in operation, including a head stack assembly of the
invention and an associated disk stack;
[0022] FIG. 11 is a side view of an embodiment of a head stack
assembly, in accordance with the invention, with a read/write head
accessing a bottom disk surface;
[0023] FIG. 12 is an end view of the configuration of the head
stack assembly of FIG. 11;
[0024] FIG. 13 is a side view of another configuration of a head
stack assembly of FIG. 11, with the read/write head accessing a top
disk surface;
[0025] FIG. 14 is an end view of the configuration of the head
stack assembly of FIG. 13;
[0026] FIG. 15 is a side view of an embodiment of a ramp for use
with the head stack assemblies of the invention;
[0027] FIG. 16 is a side view of an embodiment of a moveable ramp
for use with the head stack assemblies of the invention;
[0028] FIG. 17 is a side view of an embodiment of a moveable ramp
for use with the head stack assemblies of the invention; and
[0029] FIGS. 18A-18E are sequential top views of a portion of a
hard drive in operation, including a head stack assembly and
moveable ramp configuration in accordance with the invention.
DETAILED DESCRIPTION
[0030] The methods and features described herein are applicable to
disk drives that can be more economically priced due to reducing
the number of read/write heads in the HDD. This is accomplished by
enabling single or dual head suspension arms with attached
read/write heads to access multiple disk surfaces. This will
significantly reduce the cost of the HDD, which can be particularly
useful when large portions of the data are not being regularly
accessed by the user.
[0031] In accordance with configurations of the invention discussed
herein, a HDD with a four-disk stack having eight disk surfaces can
be provided with less than eight read/write heads. For example, an
HDD of the invention may include only one or two of such heads,
thereby eliminating the cost of the remaining six or seven
read/write heads. Such an elimination of heads in the HDD also
eliminates the need for the associated larger number of pre-amps
and other electronics, along with the larger number of actuator
arms, suspensions, and sliders that support each head. In
accordance with the invention, HDD systems are provided that reduce
the number of heads while retaining the same number of disks by
using a head stack assembly arm that can quickly translate along
the height of the disk stack to access more than one disk. This may
be accomplished by a miniature piezoelectric motor, as will be
discussed herein relative to embodiments of the invention
[0032] Referring now to the Figures, wherein the components are
labeled with like numerals throughout the several Figures, and
initially to FIGS. 2 and 3, schematic side and top views are
provided of a head stack assembly. HSA 40 generally includes a
voice coil 42, a center block 44, a first arm 46 with an associated
read/write head 48, a second arm 50 with an associated read/write
head 52, a C-shaped adaptor 54, and a piezoelectric motor 56. The
voice coil 42 is basically an actuator used to move the arms
relative to the surfaces of adjacent disks, and can be associated
with a closed-loop feedback system or servo system that is used to
dynamically position the heads directly over certain data tracks.
In operation, current is fed to the coil which generates an
electromagnetic field that causes the heads to move based on
attraction or repulsion relative to a permanent magnet. The voice
coil 42 is securely attached to the center block 44 to provide a
rotary system in which actuation of the voice coil 42 causes
rotation in a direction illustrated by reference numeral 60 about
an axis 58 that extends through center block 44. Voice coil 42 also
causes rotation in a direction opposite that illustrated by
reference numeral 60.
[0033] Adaptor 54 is referred to herein as a C-shaped adaptor 54,
although it is understood that it can have a different shape or
configuration than described and illustrated. For example, the
adaptor 54 can include flanges or other structures that provide
additional structural support or can include one or more angled
portions. For this embodiment, however, the adaptor 54 is C-shaped,
with an upper member 62 spaced from a lower member 64 by a distance
that corresponds with a vertical member 66. The outside surface of
vertical member 66 is securely connected to the center block 44,
such as with adhesive or fasteners, so that the vertical member 66
and center block 44 are not moveable relative to each other. In
addition, a threaded rod 70, along which the piezoelectric motor 56
can move, is connected at its opposite ends within the upper member
62 and lower member 64 of the adaptor 54. Because the upper and
lower members 62, 64 constrain the threaded rod 70, the motor 56 is
likewise constrained in its travel between the upper and lower
members 62, 64.
[0034] Referring additionally to the schematic cross-sectional view
of FIG. 4, the piezoelectric motor of this embodiment and other
embodiments described herein can be a miniature motor of the type
commercially available from Si Scientific Instruments GmbH of
Gilching, Germany under the trade designation "Squiggle," for
example. The motor or motor assembly 56 generally includes threaded
rod 70, a threaded member 72, and multiple plates 74 that are
referred to herein as PZT plates, as they are made from a ceramic
material such as PZT, or lead zirconate titanate
(Pb[Zr(x)Ti(1-x)]O3), although they can instead be made of a
different material. In particular, FIG. 4 illustrates a
configuration that includes four of such PZT plates 74. The
threaded rod is inlaid between two holes of the C-shaped adaptor.
The only movement allowed for the threaded rod 70 is rotation
around its own center axis. The plate 74 that is closest to the
adaptor 54 is configured and positioned so that it will be in
contact with the adaptor 54 as the motor 56 moves up and down
relative to the threaded rod 70. In this way, the plate 74 cannot
rotate while the motor 56 is moving vertically. Preferably, the
contact surfaces of the leftmost plate 74 and the inside of
vertical member 66 of adaptor 54 provide for frictionless or nearly
frictionless contact during movement of the motor 56 so that the
motor 56 can slide with very little resistance.
[0035] The first and second arms 46, 50 extend radially from an
outer surface of the piezoelectric motor 56 such that movement of
the motor 56 along the threaded rod 70 will provide the desired
vertical movement of the arms 46, 50 and their corresponding
read/write heads 48, 52. In the embodiment of FIG. 4 that includes
four plates 74, arms 46, 50 are securely attached to the rightmost
plate 74. As is illustrated in both FIGS. 3 and 4, the arms 46, 50
are configured so that their respective heads 48, 52 are not
aligned with each other when viewed from above the assembly. With
this offset, the heads 48, 52 are designed to not contact each
other even when the motor 56 is moving vertically to access certain
disk surfaces.
[0036] FIG. 5 provides for a variation of the configuration of PZT
of FIG. 4 and instead illustrates threaded rod 170, a threaded
member 172 and two PZT plates 174 positioned at the top and bottom
of the threaded member 172. As shown, the threaded member 172 is
designed so that its leftmost surface will be in contact with an
adaptor 154 as a piezoelectric motor moves up and down along a
threaded rod 170. In this way, the threaded member 172 cannot
rotate while the motor is moving the adaptor 154 vertically.
Preferably, the contact surfaces of the leftmost surface of
threaded member 172 and the inside of a vertical member of adaptor
154 provide for frictionless or nearly frictionless contact during
movement of the motor so that the adaptor 154 can slide with very
little resistance.
[0037] First and second arms 146, 150 extend radially from the
piezoelectric motor such that movement of the motor along the
threaded rod 170 will provide the desired vertical movement of the
arms 146, 150 and their corresponding read/write heads. In the
embodiment of FIG. 5 that includes two plates 174, arms 146, 150
are securely attached to the rightmost side of threaded member 172.
As with the embodiment of FIGS. 3 and 4, the arms 146, 150 are
configured so that their respective heads are not aligned with each
other when viewed from above the assembly. With this offset, the
heads are designed to not contact each other even when the motor is
moving vertically to access certain disk surfaces.
[0038] FIGS. 6 and 7 are schematic side and top views,
respectively, of a head stack assembly (HSA) 240, which generally
includes a voice coil 242, a center block 244, a first arm 246 with
an associated read/write head 248, a second arm 250 with an
associated read/write head 252, a C-shaped adaptor 254, and a
piezoelectric motor 256. Voice coil 242 is rigidly attached to the
center block 244 to provide a rotary system in which actuation of
the voice coil 242 causes rotation in a direction illustrated by
reference numeral 260 about an axis 258 that extends through center
block 244. Voice coil 242 also causes rotation in a direction
opposite that illustrated by reference numeral 260.
[0039] Adaptor 254 is referred to herein as a C-shaped adaptor 254,
although it is understood that it can have a different shape or
configuration than described and illustrated. For this embodiment,
however, the adaptor 254 is C-shaped, with an upper member 262
spaced from a lower member 264 by a distance that corresponds with
a vertical member 266. In this embodiment, adaptor 254 is oriented
in the opposite direction relative to the center block 244 such
that the outer surface of its vertical member 266 is spaced from
and facing in the same direction as the rightmost surface of center
block 244. The outside surface of motor 256 is securely connected
to the center block 244, such as with adhesive or fasteners, so
that the motor 256 and center block 244 are not moveable relative
to each other. In addition, a threaded rod 270 along which the
piezoelectric motor 256 can move is connected at its opposite ends
to the upper member 262 and lower member 264 of the adaptor 254.
Because the upper and lower members 262, 264 constrain the threaded
rod 270, the motor 256 is likewise constrained between the upper
and lower members 262, 264. In this embodiment, rotation of the
threaded rod 270 relative to motor 256 will move the C-shaped
adaptor 254 vertically relative to the center block 244 and voice
coil 242, in directions indicated by arrows 275.
[0040] Referring additionally to the schematic cross-sectional view
of FIG. 8, the piezoelectric motor can be a miniature motor of the
type discussed above relative to FIGS. 2-5, for example. The motor
256 generally includes threaded rod 270, a threaded member 272, and
multiple plates 274 that are referred to herein as PZT plates,
although they can instead be made of a different material. In
particular, FIG. 8 illustrates a configuration that includes four
of such PZT plates 274. The plate 274 that is closest to the center
block 244 (i.e., the leftmost plate 274) is securely attached to
center block 244, such as with fasteners and/or adhesives. The
plate 274 that is closest to the adaptor 254 (i.e., the rightmost
plate 274) is configured and positioned so that it will be in
contact with the adaptor 254 as the adaptor 254 moves up and down
relative to the threaded rod 270. In this way, the adaptor 254
cannot rotate while it is moving vertically. Preferably, the
contact surfaces of the rightmost plate 274 and the inside of
vertical member 266 of adaptor 254 provide for frictionless or
nearly frictionless contact during movement of the adaptor 254 so
that it can slide with very little resistance.
[0041] The first and second arms 246, 250 extend radially from the
outside surface of C-shaped adaptor 254 such that movement of the
adaptor 254 relative to the threaded rod 270 will provide the
desired vertical movement of the arms 246, 250 and their
corresponding read/write heads 248, 252. As is illustrated in both
FIGS. 6 and 7, the arms 246, 250 are configured so that their
respective heads 248, 252 are not aligned with each other when
viewed from above the assembly. With this offset, the heads 248,
252 are designed to not contact each other even when adaptor 254 is
moving vertically to access certain disk surfaces.
[0042] FIG. 9 provides for a variation of the configuration of PZT
plates discussed above relative to FIG. 8, and instead illustrates
threaded rod 370, a threaded member 372 and two PZT plates 374,
shown at the top and bottom of a threaded member 372. As shown, the
threaded member 372 is designed so that its leftmost surface is
securely attached to center block 344 and so that its rightmost
surface is slideable relative to the C-shaped adaptor 354 as
adaptor 354 moves up and down relative to threaded rod 370.
Preferably, the contact surfaces of the rightmost surface of
threaded member 372 and the inside of a vertical member of adaptor
354 provide for frictionless or nearly frictionless contact during
movement of the motor so that the motor can slide with very little
resistance.
[0043] First and second arms 346, 350 extend radially from the
outer surface of adaptor 354 such that movement of the adaptor 354
along the threaded rod 370 will provide the desired vertical
movement of the arms 346, 350 and their corresponding read/write
heads. In the embodiment of FIG. 9 that includes two plates 374,
arms 346, 350 are securely attached to the rightmost side of
adaptor 354. As with the embodiment of FIGS. 7 and 8, the arms 346,
350 are configured so that their respective heads are not aligned
with each other when viewed from above the assembly. With this
offset, the heads are designed to not contact each other even when
the adaptor 354 is moving vertically to access certain disk
surfaces.
[0044] An additional distinction between the embodiment of FIGS. 2
and 3 and the embodiment of FIGS. 6 and 7 is the installation
method of the piezoelectric motor. The PZT plates are movable and
the C-shaped adaptor is fixed in FIGS. 2 and 3, while the PZT
plates are fixed and the C shaped adaptor is movable in FIGS. 6 and
7.
[0045] FIGS. 10A-10F illustrate an exemplary method of using a head
stack assembly 400 of the present invention to access data
locations on a disk of a disk stack 402. Note that only the top
disk of the stack 402 is visible, although it is understood that
the stack 42 includes at least two disks. As shown, head stack
assembly 400 generally includes a voice coil 442, a center block
444, a first arm 446 with an associated read/write head, a second
arm 450 with an associated read/write head, a C-shaped adaptor 454,
and a piezoelectric motor (not visible), similar to the
configuration of FIGS. 2 and 3 discussed above. Voice coil 442 is
rigidly attached to the center block 444 to provide a rotary system
in which actuation of the voice coil 442 causes rotation in a
direction illustrated by reference numeral 460 about an axis 458
that extends through center block 444. Voice coil 442 also causes
rotation in a direction opposite that illustrated by reference
numeral 460. The assembly 400 further includes a threaded rod 470
positioned within adaptor 454 along which the piezoelectric motor
can move. In addition, arms 446, 450 are configured so that their
respective heads are not aligned with each other when viewed from
above the assembly.
[0046] With regard to the illustrated exemplary sequential
operation using the head stack assembly 400, FIG. 10A illustrates
the drive in its stand-by or "off" position during which the heads
associated with the arms 446, 450 are parked or resting on a ramp
480. When a signal is provided to access data tracks of one of the
disks in the stack, the voice coil provides a signal to rotate the
head stack assembly 400 about axis 458 until the read/write heads
at the ends of arms 446, 450 are positioned adjacent to opposite
sides of one of the disks, as shown in FIG. 10B. Because one of the
lower disks is being accessed in this Figure, the top disk of the
stack 402 obscures a view of the position of the distal ends of the
arms 446, 450.
[0047] Next, the drive receives a signal to read or write data on a
different disk than the one currently being accessed. In this
situation, the head stack assembly 400 rotates again about the axis
458 until the heads associated with the arms 446, 450 are located
adjacent to ramp fin 480, as illustrated in FIG. 10C. The head
stack assembly 400 continues to rotate until the arms 446, 450 are
past the ramp fin 480, as is illustrated in FIG. 10D. Because the
arms are configured so that their respective read/write heads are
offset relative to each other, they will not come in contact with
each other, even when they are free from the ramp fin 480. At this
point, the piezoelectric motor will be activated to move the head
stack assembly 400 along the threaded rod 470 to the desired
vertical position for accessing another disk, as is illustrated in
FIG. 10E. The head stack assembly 400 is then rotated back to and
then past the ramp fin 480 and toward the disk stack 402 until the
read/write heads at the ends of arms 446, 450 are positioned
adjacent to opposite sides of one of the disks, as shown in FIG.
10F. Because the disk accessed in this step of the example is the
top disk, the end of arm 446 and its associated slider and
read/write head are visible.
[0048] In order to further reduce costs from the embodiments
discussed above, another embodiment provides for a head stack
assembly that instead includes only a single arm. With this
embodiment, a common motor referred to herein as a "flipping motor"
is inserted between a proximal end of the arm and a piezoelectric
motor or C-shaped adaptor, which is activated to rotate the arm 180
degrees to access an opposite surface of a disk. In particular,
FIGS. 11-14 illustrate a head stack assembly 500, which generally
includes a voice coil 542, a center block 544, a single arm 546
with an associated read/write head 548, a C-shaped adaptor 554, and
a piezoelectric motor 556. The voice coil 542 is rigidly attached
to the center block 544 to provide a rotary system in which
actuation of the voice coil 542 causes rotation in a direction
illustrated by reference numeral 560 about an axis 558 that extends
through center block 544. Voice coil 542 also causes rotation in a
direction opposite that illustrated by reference numeral 560. A
threaded rod 570 is provided within the adaptor 554 along which the
piezoelectric motor 556 can move. The motor 556 may also include
one or more PZT plates, as is described above relative to other
embodiments of the invention.
[0049] In this embodiment, a flipping motor 584 is provided, which
includes a motor rotor 586 connected to the piezoelectric motor 556
via a motor stator 588. The arm 546 extends radially from the
flipping motor 584 such that movement of the motor 556 along the
threaded rod 570 will provide the desired vertical movement of the
arm 546 and its corresponding read/write head 548, and the flipping
motor 584 will provide the desired rotation of the arm 546 and its
corresponding read/write head 548 in a direction designated by
reference number 590. It is noted that while these figures
illustrate the C-shaped adaptor 554 in the orientation illustrated
in FIG. 2, the C-shaped adaptor 544 can instead be oriented similar
to the C-shaped adaptor 254 of FIG. 6 so that instead of the motor
stator 588 being securely attached to the piezoelectric motor 556
directly, the motor stator can instead be securely attached to the
outer vertical surface of the C-shaped adaptor 554
[0050] In operation, the head stack assembly 500 operates by
receiving a signal to access data tracks of one of the disks in a
stack, then the voice coil 542 provides a signal to rotate the head
stack assembly 500 about axis 558 until the read/write head 548 at
the end of arm 546 is positioned adjacent one side of disk 592.
Next, the drive gets a signal to read or write data on a different
side of disk 592 (and/or a different disk in the stack) than the
one currently being accessed. The head stack assembly 500 will then
rotate again about the axis 558 until the head associated with the
arm 546 is spaced from the disk 592, which may include also being
rotated past an associated ramp. At this point, the piezoelectric
motor 556 can be activated to move the head stack assembly 500
along the threaded rod 570 to the desired vertical position for
accessing another disk and/or the flipping motor 584 can be
activated to rotate the head stack assembly 180 degrees for
accessing the opposite side of disk 592 or another disk in the
stack.
[0051] Referring now to FIGS. 15-17, various versions of ramps are
illustrated and described for use with head stack assemblies of the
invention. FIG. 15 illustrates a ramp 600 that extends from a base
602, and multiple extending ramp fins 604. The number of ramp fins
604 will typically correspond with the number of disks provided in
a disk stack. With this embodiment, the ramp 600 is in a fixed
location relative to the hard disk drive and the corresponding head
stack assembly.
[0052] FIG. 16 illustrates an alternative configuration in which a
movable ramp 610 is provided, which includes a single extending
ramp fin 612. Such a configuration can further reduce costs of an
HDD by reducing the number of required ramp fins. This
configuration includes a C-shaped adaptor 614 attached to a base
616, along with a piezoelectric motor 618 that is moveable along a
threaded rod 620 positioned within the adaptor 614. The ramp 610 is
connected to an outer surface of the motor 618 so that it is
vertically movable with activation of the motor 618. In this way,
the single ramp fin 612 is positionable relative to the read/write
head(s) of the moveable head suspension assemblies of the
invention. FIG. 17 includes an alternative configuration of a ramp
650 with a single extending ramp fin 652 that operates in a similar
manner to the ramp 610, but ramp 650 is instead attached to the
outer surface of a C-shaped adaptor 654 that is in turn connected
to an outer surface of a piezoelectric motor 656. While both of the
ramp embodiments of FIGS. 16 and 17 include a single ramp fin, it
is contemplated that the number of ramp fins can be greater than
one but less than the total number of disks.
[0053] FIGS. 18A-18E illustrate the working principle of the
movable ramps discussed above in an exemplary sequential operation
using a head stack assembly 700, FIG. 18A illustrates the drive in
its stand-by or "off" position during which the heads associated
with the arms 746, 750 are parked or resting on a ramp fin 780.
When a signal is provided to access data tracks of one of the disks
in a stack 702, the voice coil provides a signal to rotate the head
stack assembly 700 until the read/write heads at the ends of arms
746, 750 are positioned adjacent to opposite sides of one of the
disks, as shown in FIG. 18B. Because one of the lower disks is
being accessed in this Figure, the top disk of the stack 702
obscures a view of the position of the distal ends of the arms 746,
750.
[0054] Next, the drive receives a signal to read or write data on a
different disk than the one currently being accessed. In this
situation, the head stack assembly 700 rotates again until the
heads associated with the arms 746, 750 are located adjacent to
ramp fin 780, as illustrated in FIG. 18C. At this point, the
piezoelectric motor will be activated to move the head stack
assembly 700 to the desired vertical position for accessing another
disk, and the piezoelectric motor associated with the ramp fin 780
will also move to be adjacent to the disk that is being accessed,
as is illustrated in FIG. 18D. The head stack assembly 700 is then
rotated back to the disk stack 702 until the read/write heads at
the ends of arms 746, 750 are positioned adjacent to opposite sides
of one of the disks, as shown in FIG. 18E. Because the disk
accessed in this step of the example is the top disk, the end of
arm 746 and its associated slider and read/write head are
visible.
[0055] The present invention has now been described with reference
to several embodiments thereof. The foregoing detailed description
and examples have been given for clarity of understanding only. No
unnecessary limitations are to be understood therefrom. It will be
apparent to those skilled in the art that many changes can be made
in the embodiments described without departing from the scope of
the invention. The implementations described above and other
implementations are within the scope of the following claims.
* * * * *