U.S. patent application number 13/340586 was filed with the patent office on 2013-07-04 for load-unload ramp structure with cantilevered fin portion configured to reduce drop shock in a hard-disk drive.
The applicant listed for this patent is Makoto Ono, Masakazu Sasaki. Invention is credited to Makoto Ono, Masakazu Sasaki.
Application Number | 20130170069 13/340586 |
Document ID | / |
Family ID | 48694617 |
Filed Date | 2013-07-04 |
United States Patent
Application |
20130170069 |
Kind Code |
A1 |
Ono; Makoto ; et
al. |
July 4, 2013 |
LOAD-UNLOAD RAMP STRUCTURE WITH CANTILEVERED FIN PORTION CONFIGURED
TO REDUCE DROP SHOCK IN A HARD-DISK DRIVE
Abstract
A load-unload ramp structure with a cantilevered fin portion to
reduce drop shock in a hard-disk drive (HDD). The load-unload ramp
structure includes a first load-unload ramp, a fin, and a bracket
portion. The first load-unload ramp is configured to lift a first
head-slider away from a magnetic-recording disk. The fin is coupled
to the first load-unload ramp and is disposed below a first parking
position of the first head-slider. The fin includes a fin base
portion and a first cantilevered fin portion. The first
cantilevered fin portion is coupled to, and extends outward from,
the fin base portion. The bracket portion is integrally attached to
the first load-unload ramp, and is configured to allow affixing the
load-unload ramp structure in a static position in a disk-enclosure
base of the HDD. A HDD including the load-unload ramp structure and
a method for providing protection from drop shock are also
provided.
Inventors: |
Ono; Makoto; (Kanagawa,
JP) ; Sasaki; Masakazu; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ono; Makoto
Sasaki; Masakazu |
Kanagawa
Kanagawa |
|
JP
JP |
|
|
Family ID: |
48694617 |
Appl. No.: |
13/340586 |
Filed: |
December 29, 2011 |
Current U.S.
Class: |
360/75 ;
G9B/21.027 |
Current CPC
Class: |
G11B 21/22 20130101 |
Class at
Publication: |
360/75 ;
G9B/21.027 |
International
Class: |
G11B 21/22 20060101
G11B021/22 |
Claims
1. A load-unload ramp structure with a cantilevered fin portion to
reduce drop shock in a hard-disk drive, said load-unload ramp
structure comprising: a first load-unload ramp configured to lift a
first head-slider away from a first recording surface of a
magnetic-recording disk; a fin coupled to said first load-unload
ramp and disposed below a first parking position of said first
head-slider on said first load-unload ramp, said fin comprising: a
fin base portion; and a first cantilevered fin portion coupled to,
and extending outward from, said fin base portion; a bracket
portion integrally attached to said first load-unload ramp, and
configured to allow affixing said load-unload ramp structure in a
static position in a disk-enclosure base of said hard-disk drive; a
second load-unload ramp configured to lift a second head-slider
away from a second recording surface of said magnetic-recording
disk; said fin coupled to said second load-unload ramp and disposed
above a second parking position of said second head-slider on said
second load-unload ramp, said fin further comprising: a second
cantilevered fin portion coupled to, and extending outward from,
said fin base portion; and wherein said bracket portion is
integrally attached to said second load-unload ramp; and wherein
said second cantilevered fin portion is separated from said first
cantilevered fin portion by a slit.
2. The load-unload ramp structure of claim 1, wherein said first
cantilevered fin portion is configured so that when said first
head-slider is parked at said first parking position said first
cantilevered fin portion is disposed facing a disk-facing side of
said first head-slider.
3. The load-unload ramp structure of claim 1, wherein said first
cantilevered fin portion is configured so that when said first
head-slider is parked at said first parking position said first
cantilevered fin portion is configured to prevent said first
head-slider and a second head-slider from striking one another.
4. (canceled)
5. The load-unload ramp structure of claim 1, wherein said second
cantilevered fin portion is configured so that when a second
head-slider is parked at said second parking position said second
cantilevered fin portion is disposed facing a disk-facing side of
said second head-slider.
6. The load-unload ramp structure of claim 1, wherein said second
cantilevered fin portion is configured so that when said second
head-slider is parked at said second parking position said second
cantilevered fin portion is configured to prevent said first
head-slider and said second head-slider from striking one
another.
7. The load-unload ramp structure of claim 1, wherein said first
cantilevered fin portion and said second cantilevered fin portion
are configured to reduce a change in pitch static angle of at least
one of said first head-slider and said second head-slider when said
hard-disk drive is dropped, compared to a change in pitch static
angle of a first head-slider and a second head-slider of a
substantially identical hard-disk drive, but with a slitless fin,
when said substantially identical hard-disk drive is similarly
dropped.
8. The load-unload ramp structure of claim 1, wherein said first
cantilevered fin portion and said second cantilevered fin portion
have less stiffness than a stiffness of a substantially similar fin
without said slit.
9. The load-unload ramp structure of claim 1, wherein said first
cantilevered fin portion and said second cantilevered fin portion
are configured to reduce an occurrence of hard errors in said
hard-disk drive after said hard-disk drive is dropped, compared
with an occurrence of hard errors in a substantially identical
hard-disk drive, but with a slitless fin, when said hard-disk drive
with said slitless fin is similarly dropped.
10. A hard-disk drive having a load-unload ramp structure with a
cantilevered fin portion to reduce drop shock, comprising: at least
one magnetic-recording disk; at least one head-slider, said
head-slider configured to access data on said magnetic recording
disk; at least one magnetic-recording head disposed at a distal end
of said head-slider, said magnetic-recording head configured to
read data from, and to write data to, said magnetic-recording disk;
and a load-unload ramp structure comprising: a first load-unload
ramp configured to lift a first head-slider away from a first
recording surface of said magnetic-recording disk; a fin coupled to
said first load-unload ramp and disposed below a first parking
position of said first head-slider on said first load-unload ramp,
said fin comprising: a fin base portion; and a first cantilevered
fin portion coupled to, and extending outward from, said fin base
portion; a bracket portion integrally attached to said first
load-unload ramp, and configured to allow affixing said load-unload
ramp structure in a static position in a disk-enclosure base of
said hard-disk drive; a second load-unload ramp configured to lift
a second head-slider away from a second recording surface of said
magnetic-recording disk; said fin coupled to said second
load-unload ramp and disposed above a second parking position of
said second head-slider on said second load-unload ramp, said fin
further comprising: a second cantilevered fin portion coupled to,
and extending outward from, said fin base portion; and wherein said
bracket portion is integrally attached to said second load-unload
ramp; and wherein said second cantilevered fin portion is separated
from said first cantilevered fin portion by a slit.
11. The hard-disk drive of claim 10, wherein said first
cantilevered fin portion is configured so that when said first
head-slider is parked at said first parking position said first
cantilevered fin portion is disposed facing a disk-facing side of
said first head-slider.
12. The hard-disk drive of claim 10, wherein said first
cantilevered fin portion is configured so that when said first
head-slider is parked at said first parking position said first
cantilevered fin portion is configured to prevent said first
head-slider and a second head-slider from striking one another.
13. (canceled)
14. The hard-disk drive of claim 10, wherein said wherein said
second cantilevered fin portion is configured so that when a second
head-slider is parked at said second parking position said second
cantilevered fin portion is disposed facing a disk-facing side of
said second head-slider.
15. The hard-disk drive of claim 10, wherein said second
cantilevered fin portion is configured so that when said second
head-slider is parked at said second parking position said second
cantilevered fin portion is configured to prevent said first
head-slider and said second head-slider from striking one
another.
16. The hard-disk drive of claim 10, wherein said first
cantilevered fin portion and said second cantilevered fin portion
are configured to reduce a change in pitch static angle of at least
one of said first head-slider and said second head-slider when said
hard-disk drive is dropped, compared to a change in pitch static
angle of a first head-slider and a second head-slider of a
substantially identical hard-disk drive, but with a slitless fin,
when said substantially identical hard-disk drive is similarly
dropped.
17. The hard-disk drive of claim 10, wherein said first
cantilevered fin portion and said second cantilevered fin portion
have less stiffness than a stiffness of a substantially similar fin
without said slit.
18. The hard-disk drive of claim 10, wherein said first
cantilevered fin portion and said second cantilevered fin portion
are configured to reduce an occurrence of hard errors in said
hard-disk drive after said hard-disk drive is dropped, compared
with an occurrence of hard errors in a substantially identical
hard-disk drive, but with a slitless fin, when said hard-disk drive
with said slitless fin is similarly dropped.
19. A method for providing protection from drop shock for at least
one head-slider in a hard-disk drive, said method comprising:
fabricating a load-unload ramp structure including a fin having a
slit, said fin including a first cantilevered fin portion and a
second cantilevered fin portion defined by said slit in said fin,
wherein said fabricating said load-unload ramp structure further
comprises injection molding said load-unload ramp structure with a
die that includes a protrusion into a cavity formed by said die to
produce said slit in said fin at a location of said protrusion when
said load-unload ramp structure is formed in said die; affixing a
bracket portion of said load-unload ramp structure to affix said
load-unload ramp structure in a static position in a disk-enclosure
base of said hard-disk drive; and parking a head-gimbal assembly
including a head-slider of said hard-disk drive at a parking
position on said load-unload ramp structure; wherein said parking
position is located adjacent to said first and second cantilevered
fin portions such that said head-slider faces at least one of said
first and second cantilevered fin portions when said head-gimbal
assembly is parked at said parking position.
20. (canceled)
Description
TECHNICAL FIELD
[0001] Embodiments of the present invention relate generally to the
field of hard-disk drives (HDDs), and protecting a HDD from the
shock of dropping a HDD.
BACKGROUND
[0002] With the advance of HDD technology, the spacing between a
magnetic-recording head and a magnetic-recording disk has become
progressively smaller, on the order of a few nanometers (nm).
Consequently, small changes in the dimensional tolerances of
internal components that can affect the head-to-disk spacing, or
fly-height, have become of greater concern. For example, dropping
an HDD can give rise to head-positioning errors, and cause errors
in the recording, or retrieval, of information stored on the
magnetic-recording disk. Thus, engineers and scientists engaged in
the development of HDDs are becoming increasingly more interested
in providing a HDD more robust in protecting against the shock of
dropping the HDD, and HDD designs that can achieve such robustness
with minimal impact on cost.
SUMMARY
[0003] Embodiments of the present invention include a load-unload
(L/UL) ramp structure with a cantilevered fin portion to reduce
drop shock in a hard-disk drive (HDD). The L/UL ramp structure
includes a first L/UL ramp, a fin, and a bracket portion. The first
L/UL ramp is configured to lift a first head-slider away from a
first recording surface of a magnetic-recording disk. The fin is
coupled to the first L/UL ramp and is disposed below a first
parking position of the first head-slider on the first L/UL ramp.
The fin includes a fin base portion and a first cantilevered fin
portion. The first cantilevered fin portion is coupled to, and
extends outward from, the fin base portion. The bracket portion is
integrally attached to the first L/UL ramp, and is configured to
allow affixing the L/UL ramp structure in a static position in a
disk-enclosure base of the HDD. Embodiments of the present
invention also include a HDD including the L/UL ramp structure with
a cantilevered fin portion to reduce drop shock, and a method for
providing protection from drop shock for at least one head-slider
in a HDD
DESCRIPTION OF THE DRAWINGS
[0004] The accompanying drawings, which are incorporated in and
form a part of this specification, illustrate embodiments of the
invention and, together with the description, serve to explain the
embodiments of the invention:
[0005] FIG. 1 is a plan view illustrating the arrangement of
components within the example environment of a hard-disk drive
(HDD) that includes a load-unload (L/UL) ramp structure with a
cantilevered fin portion to reduce drop shock, in accordance with
one or more embodiments of the present invention.
[0006] FIG. 2 is an enlarged plan view of the boxed region 2 of
FIG. 1 illustrating details of the configuration of a cantilevered
fin portion of the L/UL ramp structure of FIG. 1 with respect to a
head-slider when the head-slider is parked at a parking position
above the cantilevered fin portion, in accordance with one or more
embodiments of the present invention.
[0007] FIG. 3 is side view of the head-gimbal assemblies and a
cross-sectional view of a cross-section along line 3-3 of FIG. 2 of
the L/UL ramp structure illustrating the configuration of
cantilevered fin portions of the L/UL ramp structure of FIG. 1 with
respect to head-sliders parked at respective parking positions of a
pair of head-gimbal assemblies (HGAs) configured to access opposite
sides of a magnetic-recording disk, in accordance with one or more
embodiments of the present invention.
[0008] FIG. 4 is a perspective view illustrating the configuration
of the HDD of FIG. 1 in a tilt-drop test used to test the HDD for
robustness with respect to shock from dropping the HDD, in
accordance with one or more embodiments of the present
invention.
[0009] FIG. 5A is a perspective view of the L/UL ramp structure
illustrating the arrangement of component parts of the L/UL ramp
structure, in accordance with one or more embodiments of the
present invention.
[0010] FIG. 5B is a plan view looking down onto the L/UL ramp
structure illustrating the arrangement of component parts of the
L/UL ramp structure, in accordance with one or more embodiments of
the present invention.
[0011] FIG. 5C is another plan view looking in about an upstream
direction at an approximately downstream-facing side of the L/UL
ramp structure illustrating the arrangement of component parts of
the L/UL ramp structure, in accordance with one or more embodiments
of the present invention.
[0012] FIG. 6 is a chart comparing the stiffness of a cantilevered
fin portion, in accordance with one or more embodiments of the
present invention, to the stiffness of a substantially similar fin
without the slit, as modeled with finite element modeling
(FEM),
[0013] FIG. 7 is a chart comparing the change in pitch static angle
(PSA), .DELTA. PSA, of the fin with the slit, in accordance with
one or more embodiments of the present invention, to .DELTA. PSA of
a substantially similar fin without the slit,
[0014] FIG. 8 is flow chart illustrating a method for providing
protection from drop shock for at least one head-slider in the HDD,
in accordance with one or more embodiments of the present
invention.
[0015] The drawings referred to in this description should not be
understood as being drawn to scale except if specifically
noted.
DESCRIPTION OF EMBODIMENTS
[0016] Reference will now be made in detail to the alternative
embodiments of the present invention. While the invention will be
described in conjunction with the alternative embodiments, it will
be understood that they are not intended to limit the invention to
these embodiments. On the contrary, the invention is intended to
cover alternatives, modifications and equivalents, which may be
included within the spirit and scope of the invention as defined by
the appended claims.
[0017] Furthermore, in the following description of embodiments of
the present invention, numerous specific details are set forth in
order to provide a thorough understanding of the present invention.
However, it should be appreciated that embodiments of the present
invention may be practiced without these specific details. In other
instances, well known methods, procedures, and components have not
been described in detail as not to unnecessarily obscure
embodiments of the present invention. Throughout the drawings, like
components are denoted by like reference numerals, and repetitive
descriptions are omitted for clarity of explanation if not
necessary.
Physical Description of Embodiments of a Load-Unload (L/UL) Ramp
Structure With Cantilevered Fin Portion Configured to Reduce Drop
Shock in a Hard-Disk Drive (HDD), a HDD Including the Same, and a
Method for Providing Protection Against Drop Shock to a Head-Slider
in the HDD
[0018] Embodiments of the present invention relate to the ability
of a hard-disk drive (HDD) to withstand external impacts, and
relate, in particular, to the ability of a HDD to withstand
external impacts when it is not operating. In recent years, HDDs
have come to be used not only in information-technology (IT)
equipment such as personal computers (PCs), but have also come to
be widely used in household appliances, such as televisions and
digital video recorders (DVRs). Thus, HDDs, because of the
ubiquitous use, have to withstand external impacts. In HDDs, a
magnetic-recording head writes data to and reads data from a
magnetic-recording medium of a magnetic-recording disk by means of
the magnetic-recording head. The magnetic-recording head is formed
within a head-slider, and the head-slider that is attached to
elastic suspension by way of a flexure.
[0019] When an HDD is operating, the head-slider flies above the
rotating magnetic-recording disk with a surface of the
magnetic-recording head facing the magnetic-recording medium of the
magnetic-recording disk, referred to by the term of art, "air
bearing surface (ABS)," of the magnetic-recording head; and, a
constant gap, referred to by the term of art, "fly-height (FH)," is
maintained between the ABS of the magnetic-recording head and the
recording surface of the magnetic-recording disk. A suspension is
attached to a rotary actuator; and, when the actuator is driven,
the magnetic-recording head is held at a prescribed position over
the magnetic-recording disk so that data can be written and read.
The magnetic-recording disk is rotated within angular rotation of
5400 revolutions per minute (rpm), or alternatively 7200 rpm
depending upon the design of the HDD, by means of a spindle
motor.
[0020] Embodiments of the present invention relate to a load/unload
(L/UL) ramp structure which is used in the HDD. Embodiments of the
present invention are intended to ensure that the HDD is able to
withstand external impacts, when it is not operating, by providing
suitable stiffness for a fin that is a component part of the L/UL
ramp structure facing the ABS side of the head-slider when the
magnetic-recording head is retracted from the magnetic-recording
disk, and parked in a parking position of the L/UL ramp
structure.
[0021] As shown in and described in the discussion of FIGS. 1-8
herein, embodiments of the present invention include a L/UL ramp
structure 190 with a cantilevered fin portion, for example, at
least one of first and second cantilevered fin portions 190c-1b and
190c-2b, to reduce drop shock in a hard-disk drive (HDD) 101. The
L/UL ramp structure 190 includes a first L/UL ramp 190b-1, a fin
190c, and a bracket portion 190a. The first L/UL ramp 190b-1 is
configured to lift a first head-slider 110a and 110b away from a
first recording surface of a magnetic-recording disk 120. The fin
190c is coupled to the first L/UL ramp 190b-1 and is disposed below
a first parking position of the first head-slider 110a and 110b on
the first L/UL ramp 190b-1. The fin 190c includes a fin base
portion, including a top fin base portion 190c-1a and a bottom fin
base portion 190c-2a (see FIGS. 3 and 5A-5C), and a first
cantilevered fin portion 190c-1b. The first cantilevered fin
portion 190c-1b is coupled to, and extends outward from, the fin
base portion 190c-1a and 190c-2a. The bracket portion 190a is
integrally attached to the first L/UL ramp 190b-1, and is
configured to allow affixing the L/UL ramp structure 190 in a
static position in a disk-enclosure base 105 of the HDD 101.
[0022] As shown in and described in the discussion of FIG. 1-3
herein, embodiments of the present invention also include a HDD 101
including the L/UL ramp structure 190 with the cantilevered fin
portion, for example, first cantilevered fin portion 190c-1b (see
FIGS. 2-3 and 5A-5C), to reduce drop shock. Throughout the
following, the embodiments of the present invention for the L/UL
ramp structure 190 with a cantilevered fin portion, for example, at
least one of first and second cantilevered fin portions 190c-1b and
190c-2b, to reduce drop shock in a HDD may be understood to be also
incorporated in the environment of HDD 101.
[0023] Furthermore, as shown in and described in the discussion of
FIG. 8 herein, embodiments of the present invention also include a
method for providing protection from drop shock for at least one
head-slider in a HDD. Throughout the following, embodiments of the
present invention for the L/UL ramp structure with a cantilevered
fin portion, for example, at least one of first and second
cantilevered fin portions 190c-1b and 190c-2b of FIGS. 1-3 and
5A-5C, to reduce drop shock in a HDD and embodiments of the present
invention for the HDD including the L/UL ramp structure with the
cantilevered fin portion to reduce drop shock in the HDD may be
understood as being capable of being incorporated within certain
embodiments of the present invention for the method for providing
protection from drop shock for at least one head-slider in a
HDD.
[0024] With reference now to FIG. 1, in accordance with one or more
embodiments of the present invention, a plan view 100 of a
hard-disk drive (HDD) 101 is shown. FIG. 1 illustrates the
arrangement of components within HDD 101 that includes a L/UL ramp
structure 190 with fin 190c including a first cantilevered fin
portion 190c-1b (see FIGS. 2-3 and 5A-5C) to reduce drop shock. HDD
101 includes, without limitation thereto, at least one, a first,
head-gimbal assembly (HGA) 110 including a first magnetic-recording
head 110a, a first lead-suspension 110c attached to the first
magnetic-recording head 110a, and a first load beam 110d attached
to a first head-slider 110a and 110b, which includes the first
magnetic-recording head 110a at a distal end of a first slider
110b. As used herein, the term of art, "head-slider," refers to the
combination of a magnetic-recording head and a slider, for example,
first magnetic-recording head 110a and first slider 110b. In an
alternative embodiment of the present invention, HDD 101 may
include more than one HGA, for example, a second HGA 310 as shown
in FIG. 3, which faces first HGA 110 when disposed in a parking
position on L/UL ramp structure 190. The first head-slider 110a and
110b is attached at the distal end of the first load beam 110b to a
gimbal portion of the first load beam 110b. The first HGA 110 also
includes a first tongue portion 110e, which allows first HGA 110 to
engage the first L/UL ramp 190b-1 when the first HGA 110 is
retracted from the first recording surface of the magnetic
recording disk 120. HDD 101 also includes at least one
magnetic-recording disk 120 rotatably mounted on a spindle 126 and
a drive motor (not shown) mounted in a disk-enclosure base 105 and
attached to the spindle 126 for rotating the magnetic-recording
disk 120. The first magnetic-recording head 110a that includes a
write element, a so-called writer, and a read element, a so-called
reader, is disposed for respectively writing and reading
information, referred to by the term of art, "data," stored on the
magnetic-recording disk 120 of HDD 101. The magnetic-recording disk
120, or a plurality (not shown) of magnetic-recording disks, may be
affixed to the spindle 126 with a disk clamp 128. The disk clamp
128 is provided with fastener holes, for example, fastener hole
130, and clamps the magnetic-recording disk 120, or magnetic
recording disks (not shown), to a hub (not shown) with fasteners,
of which fastener 131 is an example. HDD 101 further includes an
arm 134 attached to first HGA 110, a carriage 136, a voice-coil
motor (VCM) that includes an armature 138 including a voice coil
140 attached to the carriage 136; and a stator 144 including a
voice-coil magnet (not shown); the armature 138 of the VCM is
attached to the carriage 136 and is configured to move the arm 134
and first HGA 110 to access portions of the magnetic-recording disk
120, as the carriage 136 is mounted on a pivot-shaft 148 with an
interposed pivot-bearing assembly 152.
[0025] With further reference to FIG. 1, in accordance with one or
more embodiments of the present invention, electrical signals, for
example, current to the voice coil 140 of the VCM, write signals to
and read signals from the first magnetic-recording head 110a, are
provided by a flexible cable 156. Interconnection between the
flexible cable 156 and the first magnetic-recording head 110a may
be provided by an arm-electronics (AE) module 160, which may have
an on-board pre-amplifier for the read signal, as well as other
read-channel and write-channel electronic components. The flexible
cable 156 is coupled to an electrical-connector block 164, which
provides electrical communication through electrical feedthroughs
(not shown) provided by the disk-enclosure base 105. The
disk-enclosure base 105, also referred to as a base casting,
depending upon whether the disk-enclosure base 105 is cast, in
conjunction with an HDD cover (not shown) provides a sealed
protective disk enclosure for the information storage components of
HDD 101.
[0026] With further reference to FIG. 1, in accordance with one or
more embodiments of the present invention, other electronic
components (not shown), including a disk controller and servo
electronics including a digital-signal processor (DSP), provide
electrical signals to the drive motor, the voice coil 140 of the
VCM and the first magnetic-recording head 110a of first HGA 110.
The electrical signal provided to the drive motor enables the drive
motor to spin providing a torque to the spindle 126 which is in
turn transmitted to the magnetic-recording disk 120 that is affixed
to the spindle 126 by the disk clamp 128; as a result, the
magnetic-recording disk 120 spins in a direction 172. The spinning
magnetic-recording disk 120 creates an airflow including an
air-stream, and a self-acting air bearing on which the air-bearing
surface (ABS) of the first head-slider 110a and 110b rides so that
the first head-slider 110a and 110b flies in proximity with the
first recording surface of the magnetic-recording disk 120 to avoid
contact with a thin magnetic-recording medium of the
magnetic-recording disk 120 in which information is recorded. The
electrical signal provided to the voice coil 140 of the VCM enables
the first magnetic-recording head 110a of first HGA 110 to access a
track 176 on which information is recorded. As used herein,
"access" is a term of art that refers to operations in seeking the
track 176 of the magnetic-recording disk 120 and positioning the
first magnetic-recording head 110a on the track 176 for both
reading data from, and writing data to, the magnetic-recording disk
120. The armature 138 of the VCM swings through an arc 180 which
enables first HGA 110 attached to the armature 138 by the arm 134
to access various tracks on the magnetic-recording disk 120.
Information is stored on the magnetic-recording disk 120 in a
plurality of concentric tracks (not shown) arranged in sectors on
the magnetic-recording disk 120, for example, sector 184.
Correspondingly, each track is composed of a plurality of sectored
track portions, for example, sectored track portion 188. Each
sectored track portion 188 is composed of recorded data and a
header containing a servo-burst-signal pattern, for example, an
ABCD-servo-burst-signal pattern, information that identifies the
track 176, and error correction code information. In accessing the
track 176, the read element of the first magnetic-recording head
110a of first HGA 110 reads the servo-burst-signal pattern which
provides a position-error-signal (PES) to the servo electronics,
which controls the electrical signal provided to the voice coil 140
of the VCM, enabling the first magnetic-recording head 110a to
follow the track 176. Upon finding the track 176 and identifying a
particular sectored track portion 188, the first magnetic-recording
head 110a either reads data from the track 176, or writes data to,
the track 176 depending on instructions received by the disk
controller from an external agent, for example, a microprocessor of
a computer system.
[0027] As used herein, component parts of HDD 101 have different
sides referred to by at least the following terms of art: a side
facing an inside diameter (ID) of a magnetic-recording disk, for
example, similar to the magnetic-recording disk 120, referred to
herein as an ID side, which is applicable to component parts
situated between the ID and outside diameter of the
magnetic-recording disk; a side facing an outside diameter (OD) of
the magnetic-recording disk, an OD side, which likewise is
applicable to component parts situated between the ID and OD of the
magnetic-recording disk; for example, the magnetic recording disk
120 has an ID side 122 and an OD side 124; a side facing into the
direction 172 of motion of the magnetic-recording disk and, thus,
into the direction of airflow, a leading-edge (LE) side; a side
facing away from the direction 172 of motion of the
magnetic-recording disk and, thus, away from the direction of
airflow, a trailing-edge (TE) side; a side, or portion, of a
component facing towards the bottom of the disk-enclosure base 105,
a bottom side, or bottom portion, respectively; a side, or portion,
of a component facing away from the bottom of the disk-enclosure
base 105 and, thus, towards the disk-enclosure cover (not shown), a
top side, or top portion, respectively; a side, or portion, of a
component facing the recording surface of the magnetic-recording
disk, a disk-facing side, or disk-facing portion, respectively;
and, a side, or portion, of a component facing away from and
opposite to a side facing the recording surface of the
magnetic-recording disk, an opposite-to-disk-facing side, or
opposite-to-disk-facing portion, respectively.
[0028] As shown in FIG. 1, a triad of arrows 194, 196 and 198 is
used to indicate the relative orientation of components in HDD 101;
the direction of arrow 196 is about parallel to the long side of
the disk-enclosure base 105 of HDD 101; the direction of arrow 194
is perpendicular to arrow 196 and is about parallel to the short
side of the disk-enclosure base 105 of HDD 101; and, arrow 198,
which is indicated by the arrow head of arrow 198, is about
perpendicular to the plane of the disk-enclosure base 105, as well
as the plane of the first recording surface of the magnetic
recording disk 120, and therefore is perpendicular to arrows 194
and 196. Thus, the triad of arrows 194, 196 and 198 are related to
one another by the right-hand rule for vectors in the direction of
the arrows 194, 196 and 198 such that the cross product of the
vector corresponding to arrow 194 and the vector corresponding to
arrow 196 produces a vector parallel and oriented in the direction
of the arrow 198. The triad of arrows 194, 196 and 198 is
subsequently used to indicate the orientation of views for
subsequently described drawings of the L/UL ramp structure 190, of
which FIG. 2, which shows an enlarged view of box 2 of FIG. 1, is
an example that is next described.
[0029] With reference now to FIG. 2, in accordance with one or more
embodiments of the present invention, an enlarged plan view 200 of
the boxed region 2 of FIG. 1 is shown. FIG. 2 shows details of the
configuration of the cantilevered fin portion 190c-1b of the L/UL
ramp structure 190 of FIG. 1 with respect to a first head-slider
110a and 110b when the first head-slider 110a and 110b is parked at
a parking position above the cantilevered fin portion 190c-1b. As
shown in FIG. 2, the triad of arrows 194, 196 and 198 indicates the
orientation in which the L/UL ramp structure 190 is viewed in the
plan view 200 relative to the plan view 100 of FIG. 1. In
accordance with one or more embodiments of the present invention,
the first cantilevered fin portion 190c-1b is configured so that
when the first head-slider 110a and 110b is parked at the first
parking position the first cantilevered fin portion 190c-1b is
disposed facing a disk-facing side of the first head-slider 110a
and 110b. As shown in FIG. 2, the top fin portion 190c-1 (see FIGS.
3 and 5A-5C) of fin 190c includes the top fin base portion 190c-1a
and the first cantilevered fin portion 190c-1b, which by way of
example is a top cantilevered fin portion, without limitation
thereto. When HDD 101 is not operating, the first
magnetic-recording head 110a is retracted onto a first L/UL ramp
190b-1, by way of example, a top L/UL ramp, without limitation
thereto, positioned away from the OD side 124 of the
magnetic-recording disk 120. This is done so that if there is an
impact when HDD 101 is not operating, the first head-slider 110a
and 110b is prevented from jumping over the magnetic-recording disk
120, and the reaction thereof causing the first head-slider 110a
and 110b to strike the magnetic-recording disk 120, a phenomenon
which is referred to by the term of art, "head slap," thereby
scratching the first recording surface of the magnetic-recording
disk 120, where data is recorded. The L/UL ramp portion 190b is
provided with a fin 190c, and is designed so that the facing
head-sliders, which by way of example are the first head-slider
110a and 110b and a second head-slider 310a and 310b (see FIG. 3),
above and below the fin 190c do not directly touch each other. This
is because head slap also occurs on the L/UL ramp portion 190b due
to impacts when HDD 101 is not operating; and, therefore, there is
a risk of such impacts damaging the head-sliders if there is no fin
190c.
[0030] With further reference to FIG. 2 and reference to FIGS. 3
and 5A-5C, in accordance with one or more embodiments of the
present invention, a second triad of arrows 294, 296 and 198 is
shown that indicates the orientation of the bracket portion 190a
relative to the airflow direction above the magnetic-recording disk
120 in HDD 101. As shown in FIG. 2, the direction of arrow 296 is
about parallel to the LE side of the bracket portion 190a of the
L/UL ramp portion 190b; the direction of arrow 294 is perpendicular
to arrow 296 and is perpendicular to the LE side of the bracket
portion 190a of the L/UL ramp portion 190b; and, the arrow 198,
which is indicated by the arrow head of arrow 198, is about
perpendicular to the plane of the disk-enclosure base 105, as well
as the plane of the first recording surface of the magnetic
recording disk 120, as previously described, and is also
perpendicular to arrows 294 and 296. The second triad of arrows
294, 296 and 198 is useful for indicating the orientation of
component parts of the L/UL ramp structure 190 shown in FIG. 2, as
well as views for the subsequently described drawings of the L/UL
ramp structure 190 that are shown in FIGS. 3 and 5A-5C.
[0031] With reference now to FIG. 3, in accordance with one or more
embodiments of the present invention, a combined side and
cross-sectional view 300 is shown of the first and second HGAs 110
and 310 and a cross-section along line 3-3 of FIG. 2 of the L/UL
ramp structure 190, respectively. FIG. 3 shows the configuration of
first and second cantilevered fin portions 190c-1b and 190c-2b of
the L/UL ramp structure 190 of FIG. 1 with respect to the first
head-slider 110a and 110b, and a second head-slider 310a and 310b,
respectively, parked at respective parking positions of the pair of
first and second HGAs 110 and 310 that are configured to access
opposite sides of the magnetic-recording disk 120. As shown in FIG.
3, the triad of arrows 294, 296 and 198 indicates the orientation
in which the L/UL ramp structure 190 is viewed in the combined side
and cross-sectional view 300 relative to the plan view 200 of FIG.
2. As shown in FIG. 3, in accordance with one or more embodiments
of the present invention, the second HGA 310 includes a second
magnetic-recording head 310a, a second lead-suspension 310c
attached to the second magnetic-recording head 310a, and a second
load beam 310d attached to a second head-slider 310a and 310b,
which includes the second magnetic-recording head 310a at a distal
end of a second slider 310b. The second head-slider 310a and 310b
is attached at the distal end of the second load beam 310d to a
gimbal portion of the second load beam 310d. The second HGA 310
also includes a second tongue portion 310e, which allows second HGA
310 to engage a second L/UL ramp 190b-2 when the second HGA 310 is
retracted from the bottom, or second, recording surface of the
magnetic recording disk 120. As shown in FIG. 3, the fin 190c
includes a first, or top, fin base portion 190c-1a, a first, or
top, cantilevered fin portion 190c-1b, a second, or bottom, fin
base portion 190c-2a, and a second, or bottom, cantilevered fin
portion 190c-2b. The fin base portion includes the first, or top,
fin portion 190c-1, and the second, or bottom, fin portion 190c-2.
The fin 190c is provided with a slit 190c-3 that defines the first
cantilevered fin portion 190c-1b and the second cantilevered fin
portion 190c-2b. Thus, in accordance with embodiments of the
present invention, the stiffness of the fin 190c is reduced in
comparison with a fin without the slit 190c-3. Also, as shown in
FIG. 3, the L/UL ramp portion 190b includes a first, or top, L/UL
ramp 190b-1, and a second, or bottom, L/UL ramp 190b-2. As shown in
FIG. 3, the first HGA 110 and the second HGA 310 are positioned at
their respective parking positions on the first, or top, L/UL ramp
190b-1, and the second, or bottom, L/UL ramp 190b-2, respectively.
The first, or top, L/UL ramp 190b-1 and the second, or bottom, L/UL
ramp 190b-2 are shown, respectively, with their first and second
tongue portions 110e and 310e at the parking positions on
respective first and second L/UL ramps 190b-1 and 190b-2.
[0032] With further reference to FIG. 3, in accordance with one or
more embodiments of the present invention, the first cantilevered
fin portion 190c-1b is configured so that when the first
head-slider 110a and 110b is parked at the first parking position
the first cantilevered fin portion 190c-1b is configured to prevent
the first head-slider 110a and 110b and a second head-slider 310a
and 310b from striking one another. In accordance with one or more
embodiments of the present invention, the second cantilevered fin
portion 190c-2b is configured so that when a second head-slider
310a and 310b is parked at the second parking position the second
cantilevered fin portion 190c-2b is disposed facing a disk-facing
side of the second head-slider 310a and 310b. In accordance with
one or more embodiments of the present invention, the second
cantilevered fin portion 190c-2b is configured so that when the
second head-slider 310a and 310b is parked at the second parking
position the second cantilevered fin portion 190c-2b is configured
to prevent the first head-slider 110a and 110b and the second
head-slider 310a and 310b from striking one another.
[0033] With further reference to FIG. 3, in accordance with one or
more embodiments of the present invention, with respect to pitch
static angle (PSA) 305 and hard errors, the first head-slider 110a
and 110b is attached to the suspension by way of the flexure. The
flexure is a thin, flexible leaf spring, and has the role of
holding the first head-slider 110a and 110b at the correct flying
position when HDD 101 is operating. In order to maintain the
correct FH, the tilt of the first head-slider 110a and 110b in the
lengthwise direction of the suspension, in other words the PSA 305,
has to be kept within a specific range. If the PSA 305 has a value
greater than a value within the specific range, the PSA is said to
have a change in PSA, .DELTA. PSA, greater than the operational
PSA. If the PSA 305 has a value less than a value within the
specific range, the PSA is said to have a change in PSA, .DELTA.
PSA, less than the operational PSA. If an excessive external impact
is received when HDD 101 is not operating, the first head-slider
110a and 110b may be strongly affected by head slap, and the
flexure may plastically deform. This deformation may be observed as
the amount of change in the PSA, .DELTA. PSA. If the deformation of
the flexure produces a large change in the PSA, .DELTA. PSA, the
first head-slider 110a and 110b may no longer be able to fly stably
above the first recording surface of the magnetic-recording disk
120 when HDD 101 is operating. As a result, irreparable errors,
referred to by the term of art, "hard errors," may occur when data
is written and/or read. Similar arguments also apply to PSA 315 of
the second head-slider 310a and 310b of the second HGA 310. A test
used to measure the susceptibility of a HDD to the occurrence of
such hard errors is next described.
[0034] With reference now to FIG. 4, in accordance with one or more
embodiments of the present invention, a perspective view 400 is
shown of the configuration of HDD 101 of FIG. 1 in a tilt-drop test
used to test the HDD 101 for robustness with respect to shock from
dropping HDD 101. A test known as the tilt-drop test is used as a
test for confirming the resistance of a non-operating HDD, for
example HDD 101, to impacts. In the tilt-drop test, one of the
short sides of HDD 101 is disposed parallel to a rotational axis
405 of a test jig (not shown;, and, the main body of HDD 101 is
rotated and raised from a reference surface 410 to a specific
position, from where HDD 101 is allowed to drop naturally and
strike the reference surface 410. The reference surface 410 is made
of a specific wooden material. In the tilt-drop test, the short
side of a single HDD where the rotational axis is located is
changed; and, the HDD is dropped once for each side, making a total
of four tests. After the tilt-drop test has been performed, a data
reading/writing test is carried out using HDD 101, which has been
dropped. This data reading/writing test requires that no
irreparable errors, "hard errors," have occurred. The tilt-drop
test may be performed on a plurality of HDDs; and, the passing the
test consists in no hard errors occurring in any of the HDDs. That
is, even if one hard error has occurred in only one HDD, this is
counted as a failure of the tilt-drop test by the HDD. The
tilt-drop test has the most stringent conditions of any test for
external impact during non-operation. Head slap occurs due to the
impact in the test; and, the first head-slider 110a and 110b jumps
on the top, or first, L/UL ramp 190b-1 and strikes the fin 190c. If
the flexure deforms excessively at this point and undergoes plastic
deformation, the PSA goes beyond the permitted range, and hard
errors occur.
[0035] With respect to the relationship with FH, in recent compact
HDDs, the FH has continued to decrease as the recording density has
become higher, with the FH value now reaching approximately 10
nanometers (nm). As the FH decreases, the sensitivity of PSA to
hard errors increases. In other words, if the design of
magnetic-recording head and magnetic-recording disk is changed, and
FH is reduced in order to increase the storage capacity of products
which are under development, then hard errors also occur in HDDs
that previously passed the tilt-drop test without any problem, even
if the test is performed under the same conditions. The issue
addressed by embodiments of the present invention lies in providing
a HDD with reduced FH that is still able to withstand the same
tilt-drop test, as in the prior art.
[0036] With reference now to FIGS. 5A-5C, in accordance with one or
more embodiments of the present invention, FIG. 5A is a perspective
view 500A of the L/UL ramp structure 190; FIG. 5B is a plan view
500B looking down onto the L/UL ramp structure 190; and, FIG. 5C is
another plan view 500C looking in about an upstream direction at an
approximately downstream-facing side of the L/UL ramp structure
190. As shown in FIGS. 5A-5C, the triad of arrows 294, 296 and 198
indicates the orientation in which the L/UL ramp structure 190 is
viewed in the perspective views 500A, 500B and 500C relative to the
combined side and cross-sectional view 300 of FIG. 3 and the plan
view 200 of FIG. 2. FIGS. 5A-5C show the arrangement of component
parts of the L/UL ramp structure 190. As previously described above
in the discussion of FIGS. 1-3, the L/UL ramp structure 190
includes a bracket portion 190a, a L/UL ramp portion 190b, and a
fin 190c. The L/UL ramp portion 190b includes a first, or top, L/UL
ramp 190b-1, and a second, or bottom, L/UL ramp 190b-2. As shown in
FIGS. 5A-5C, the fin 190c includes a first, or top, fin base
portion 190c-1a, a first, or top, cantilevered fin portion 190c-1b,
a second, or bottom, fin base portion 190c-2a, and a second, or
bottom, cantilevered fin portion 190c-2b. The fin base portion
includes the first, or top, fin portion 190c-1, and the second, or
bottom, fin portion 190c-2. The fin 190c is provided with a slit
190c-3 that defines the first cantilevered fin portion 190c-1b and
the second cantilevered fin portion 190c-2b.
[0037] With further reference to FIGS. 5A-5C, in accordance with
one or more embodiments of the present invention, the L/UL ramp
structure 190 may further include a second L/UL ramp 190b-2, and a
second cantilevered fin portion 190c-2b. The second L/UL ramp
190b-2 is configured to lift a second head-slider 310a and 310b
away from a second, or bottom, recording surface of the
magnetic-recording disk 120. The fin 190c is coupled to the second
L/UL ramp 190b-2 and is disposed above a second parking position of
the second head-slider 310a and 310b on the second L/UL ramp
190b-2. The fin 190c further includes a second cantilevered fin
portion 190c-2b that is coupled to, and extends outward from, the
fin base portion 190c-2a. The bracket portion 190a is integrally
attached to the second L/UL ramp 190b-2. The second cantilevered
fin portion 190c-2b is separated from the first cantilevered fin
portion 190c-1b by the slit 190c-3.
[0038] Conventional magnetic-recording disks which are used in HDDs
enable magnetic recording on both surfaces. A magnetic-recording
head, similar to first magnetic-recording head 110a, is therefore
disposed on each of the bottom surface and the top surface of a
magnetic-recording disk, similar to magnetic-recording disk 120,
and the two magnetic-recording heads, top and bottom, are used as a
pair. An even number of magnetic-recording heads is therefore often
used in an HDD.
[0039] From the point of view of designing the L/UL ramp structure
190, the attached structure has a single fin 190c for the two
magnetic-recording heads, which form the top and bottom pair. This
is because the top and bottom magnetic-recording heads are
positioned very close together, so there is no space to provide two
fins corresponding to each head.
[0040] Furthermore, the L/UL ramp structure 190 has a very complex
shape so it is produced as a plastic molded article. The fin 190c
is molded as a substantially elliptical cylinder including a planar
region facing the top and bottom magnetic-recording heads. The fact
that the fin 190c is cylindrical makes it possible to ensure
precise component dimensions because the component is endowed with
a uniform wall thickness. Accordingly, it is the overall stiffness
of the fin 190c of the L/UL ramp structure 190 that blocks head
slap that occurs when the non-operating HDD is subjected to an
external impact.
[0041] According to embodiments of the present invention, the
stiffness of the fin 190c is adjusted by providing a slit 190c-3 in
the fin 190c. The stiffness of the fin 190c can be adjusted by
varying the width and depth of the slit 190c-3; and, therefore, it
is possible to determine the shape of the slit 190c-3 with
reference to the tilt-drop test results. The fin 190c is
substantially divided into two portions, top and bottom, by
providing the slit 190c-3. The portion of the fin 190c facing the
top, or first, magnetic-recording head 110a on the upper side of
the slit 190c-3 forms a single, first cantilevered fin portion
190c-1b from the base of the slit 190c-3 to the tip end of the fin
190c. As a result, the stiffness of the fin 190c is rather low
compared with an arrangement in which the outer periphery of a fin
without a slit 190c-3 is joined in the form of a tube. Thus, in
accordance with embodiments of the present invention, by reducing
the stiffness of a fin, as for fin 190c with reduced stiffness, it
is possible to absorb head slap when an external impact is received
due to bending of the fin 190c; and, variations in the PSA, .DELTA.
PSA, can be kept to a low level. As a result, it is possible to
pass the tilt-drop test.
[0042] Moreover, the slit 190c-3 according to embodiments of the
present invention can be formed in a simple manner by adjusting the
shape of an insert pin, which is used for shaping the fin 190c,
which is subsequently described, which is one component of the mold
for forming the L/UL ramp structure 190. This means that there is a
further advantage in that application of the present invention does
not involve high costs.
[0043] By way of example, in accordance with embodiments of the
present invention, in HDD 101, two magnetic-recording heads, top
and bottom, 110a and 310a may be disposed at the respective top and
bottom sides of a single magnetic-recording disk 120, without
limitation thereto. The L/UL ramp structure 190, therefore, has one
fin 190c. The fin 190c has a shape in which a slit 190c-3 in the
lengthwise direction of the L/UL ramp portion 190b is formed in the
cylindrical section of the fin 190c, which has a substantially
elliptical in shape. The slit 190c-3 divides the fin 190c
substantially into two cantilevers at the top and bottom, a first
cantilevered fin portion 190c-1b and second cantilevered fin
portion 190c-2b.
[0044] Specifically, the shape of the fin 190c in HDD 101 has a gap
of approximately 1.3 millimeters (mm) at the surfaces where the top
and bottom head-sliders 110a and 110b, and 310a and 310b,
respectively, are received. Furthermore, the height of the fin 190c
is approximately 2.1 mm; and, the wall thickness of the cylindrical
part of the fin 190c is approximately 0.25 mm.
[0045] In order to impart a cylindrical shape to the fin 190c, the
mold for shaping the L/UL ramp structure 190 has a rod-like molding
component known as an insert pin which is inserted to around 2 mm
in the center of the fin 190c (not depicted). By this means, a fin
190c having a uniform wall thickness is formed around the insert
pin. The slit 190c-3, in one embodiment of the present invention,
can be formed simply by changing the shape of the insert pin. That
is, a protruding shape, which has the width and length of the slit
190c-3 to be formed, is made at the tip end of the insert pin (not
depicted) of the die used in molding the L/UL ramp structure 190.
The width and depth of the slit 190c-3 in the fin 190c can be
adjusted by changing the protruding shape.
[0046] With now reference to FIG. 6, a chart is shown that compares
the stiffness of a cantilevered fin portion, for example, first
cantilevered fin portion 190c-1b, in accordance with one or more
embodiments of the present invention, to the stiffness of a
substantially similar fin without the slit 190c-3. As shown in FIG.
6, in accordance with embodiments of the present invention,
substantially independent cantilever-shaped parts, first
cantilevered fin portion 190c-1b and second cantilevered fin
portion 190c-2b of the fin 190c facing each for the top and bottom
head-sliders 110a and 110b, and 310a and 310b, respectively, are
formed; and, the stiffness of the fin 190c is reduced by
approximately 55% compared with a conventional fin without a slit
190c-3. Thus, in accordance with embodiments of the present
invention, the first cantilevered fin portion 190c-1b and the
second cantilevered fin portion 190c-2b have less stiffness than a
stiffness of a substantially similar fin without the slit
190c-3.
[0047] Embodiments of the present invention are characterized in
that the fin 190c of the L/UL ramp structure 190 used in HDD 101 is
provided with a slit 190c-3; and, as a result, respective dedicated
fins are substantially provided for each of the top and bottom
magnetic-recording heads 110a and 110b, and 310a and 310b,
respectively. Moreover, the stiffness of the fin 190c is adjusted
by adjusting the shape of the slit 190c-3. As a result, it is
possible to pass the tilt-drop test. The exemplary embodiment
introduced above relates to an example in which the HDD 101 employs
only one 3.5-inch magnetic-recording disk 120, but the present
invention may of course be applied without limitation to HDDs
employing a plurality of magnetic-recording disks, and to HDDs in
which one or more 2.5-inch magnetic-recording disks are
employed.
[0048] With now reference to FIG. 7, a chart is shown that compares
the change in PSA, .DELTA. PSA, of the fin 190c with the slit
190c-3, in accordance with one or more embodiments of the present
invention, to .DELTA. PSA of a substantially similar fin without
the slit 190c-3. FIG. 7 shows the results of a tilt-drop test
involving the abovementioned 3.5-inch HDD 101 in the case when a
L/UL ramp structure 190 having a fin 190c with the slit 190c-3
according to embodiments of the present invention was used, and the
case when a conventional L/UL ramp structure was used. The slit
190c-3 formed had a width of 0.8 mm and a depth of 1.0 mm. When a
conventional L/UL ramp structure was used, hard errors occurred in
all four HDDs which underwent the tilt-drop test, and the test
could not be passed. Two of the four HDDs could no longer be
started and data write errors occurred in head 1 in the other two
HDDs.
[0049] The PSA change distribution was then investigated for the
magnetic-recording heads which had been subjected to an external
impact by means of the tilt-drop test. FIG. 7 shows the normalized
PSA change amounts before and after the tilt-drop test. 0 indicates
no change in the PSA before and after the test, and 100 indicates
the PSA change amount at the boundary value where hard errors start
to occur. That is, the change amount lies within the permitted
range if it is within .+-.100, and hard errors do not arise in the
HDD, so the tilt-drop test can be passed.
[0050] As a result, when a conventional L/UL ramp structure was
used, the PSA change for the top magnetic-recording head (head 1),
similar to first magnetic-recording head 110a, went beyond the
permitted range. The PSA change distribution was broad in the case
of the other magnetic-recording head, which was the bottom
magnetic-recording head (head 0), similar to second
magnetic-recording head 310a, but remained within the permitted
range. Moreover, hard errors occurred in all head 1 type
magnetic-recording heads, so it could be confirmed that hard errors
occurred in the HDDs due to excessive change in the PSA.
[0051] On the other hand, when the L/UL ramp structure 190 having a
fin 190c with the slit 190c-3 according to embodiments of the
present invention was used, hard errors did not occur in any of the
HDDs, which underwent the tilt-drop test; and, the test could be
passed. When the PSA change distribution after the tilt-drop test
was investigated in the same way, it could be confirmed that the
PSA change distribution range in both the top magnetic-recording
heads (heads 1) and bottom magnetic-recording heads (heads 0) was
less than for the HDDs having a L/UL ramp structure that included a
fin without the slit 190c-3. The PSA change distribution in the top
magnetic-recording heads (heads 1) was within the permitted range,
so hard errors did not occur. Thus, in accordance with embodiments
of the present invention, the first cantilevered fin portion
190c-1b and the second cantilevered fin portion 190c-2b are
configured to reduce an occurrence of hard errors in HDD 101 after
HDD 101 is dropped, compared with an occurrence of hard errors in a
substantially identical HDD, but with a slitless fin, fin without a
slit 190c-3, when the HDD with the slitless fin, fin without a slit
190c-3, is similarly dropped.
[0052] With now reference to FIG. 8, in accordance with one or more
embodiments of the present invention, a flow chart 800 is shown of
a method for providing protection from drop shock for at least one
head-slider in a hard-disk drive. The method includes the following
operations. At 810, fabricating a load-unload ramp structure is
fabricated that includes a fin having a slit; the fin includes a
first cantilevered fin portion and a second cantilevered fin
portion defined by the slit in the fin. At 820, affixing a bracket
portion of the load-unload ramp structure is affixed to a
disk-enclosure base of the hard-disk drive. Thus, the load-unload
ramp structure is affixed in a static position in a disk-enclosure
base of the hard-disk drive. At 830, a head-gimbal assembly, which
includes a head-slider of the hard-disk drive, is parked at a
parking position on the load-unload ramp structure. The parking
position is located adjacent to the first and second cantilevered
fin portions such that the head-slider faces at least one of the
first and second cantilevered fin portions when the head-gimbal
assembly is parked at the parking position. At 840, fabricating the
load-unload ramp structure may also include injection molding the
load-unload ramp structure with a die that includes a protrusion
into a cavity formed by the die to produce the slit in the fin at a
location of the protrusion when the load-unload ramp structure is
formed in the die.
[0053] The foregoing descriptions of specific embodiments of the
present invention have been presented for purposes of illustration
and description. They are not intended to be exhaustive or to limit
the invention to the precise forms disclosed, and many
modifications and variations are possible in light of the above
teaching. The embodiments described herein were chosen and
described in order to best explain the principles of the invention
and its practical application, to thereby enable others skilled in
the art to best utilize the invention and various embodiments with
various modifications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
defined by the Claims appended hereto and their equivalents.
* * * * *