Title: Disk drive having a shroud assembly for shielding at least one of a flex cable and an actuator arm
Abstract: A shroud assembly for a disk drive that includes a rotatable disk, a printed circuit board, a data transfer head, an actuator assembly and a flex cable, includes a cable shrouding portion. The shroud assembly also includes a disk shrouding portion and a cable mounting portion. The cable mounting portion includes a first surface and a second surface. The first surface is configured to receive a transition portion of the flex cable proximate to a second end. The second surface is configured to receive the second end of the flex cable and to position the second end for engagement by the printed circuit board. The cable shrouding portion is configured to shield a spanning portion of the flex cable between the cable mounting portion and the actuator assembly from airflow generated by the rotation of the rotatable disk.
Patent Number: 6,865,055 Issued on 03/08/2005 to Ou-Yang, et al.
| Inventors:
|
Ou-Yang; Jin Hui (San Jose, CA);
Yang; Lin (San Jose, CA)
|
| Assignee:
|
Western Digital Technologies, Inc. (Lake Forest, CA)
|
| Appl. No.:
|
086470 |
| Filed:
|
February 28, 2002 |
| Current U.S. Class: |
360/97.03 |
| Intern'l Class: |
G11B 033//14 |
| Field of Search: |
360/264.2,97.02,97.03
|
References Cited [Referenced By]
U.S. Patent Documents
| 5898545 | Apr., 1999 | Schirle.
| |
| 5907453 | May., 1999 | Wood et al. | 360/97.
|
| 6125003 | Sep., 2000 | Tsuda et al.
| |
| 6236533 | May., 2001 | Forbord et al. | 360/98.
|
| 6369977 | Apr., 2002 | Imai et al. | 360/97.
|
| 6369978 | Apr., 2002 | Shimizu et al. | 360/97.
|
| Foreign Patent Documents |
| 07320478 | Dec., 1995 | JP | .
|
Primary Examiner: Davis; David
Attorney, Agent or Firm: Shara, Esq.; Milad G.
Knobbe, Martens, Olson & Bear, LLP
Claims
What is claimed is:
1. A shroud assembly for a disk drive that includes a rotatable disk, a
printed circuit board, a data transfer head, an actuator assembly that
positions the data transfer head with respect to the rotatable disk, and a
flex cable that interconnects the actuator assembly and the printed
circuit board, the flex cable having a first end connected to the actuator
assembly and a second end connectable to the printed circuit board, the
shroud assembly comprising:
a disk shrouding portion;
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive and to restrain a transition
portion of the flex cable proximate to the second end, the second surface
configured to receive the second end of the flex cable and to position the
second end for engagement by the printed circuit board; and
a cable shrouding portion configured to shield a spanning portion of the
flex cable between the cable mounting portion and the actuator assembly
from airflow generated by the rotation of the rotatable disk;
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
2. The shroud assembly of claim 1, wherein the disk shrouding portion, the
cable mounting portion, and the cable shrouding portion are integrally
formed.
3. The shroud assembly of claim 1, wherein the cable shrouding portion
further comprises a distal end, a mounted end, a first edge proximate the
cable mounting portion, a second edge opposite the first edge, a length
being the distance between the distal end and the mounted end, and a width
being the distance between the first edge and the second edge, the length
being about two times the width.
4. The shroud assembly of claim 1, wherein the cable shrouding portion is
about as long as the disk shrouding portion.
5. The shroud assembly of claim 1, wherein the cable shrouding portion
forms an arc having an inside surface, the inside surface located on a
side of the shroud assembly opposite the cable mounting portion.
6. The shroud assembly of claim 1, wherein the cable shrouding portion
forms an arc having an inside surface, the inside surface of the arc and
the cable mounting portion facing generally the same direction.
7. The shroud assembly of claim 1, wherein the first surface of the cable
mounting portion is generally perpendicular to the second surface of the
cable mounting portion.
8. The shroud assembly of claim 1, further comprising a shroud assembly
mounting portion that is configured to be connected to a base of the disk
drive.
9. The shroud assembly of claim 8, wherein the second surface of the cable
mounting portion comprises at least a portion of the shroud assembly
mounting portion.
10. The shroud assembly of claim 1, wherein the cable shrouding portion
further comprises a first cable shrouding portion and a second cable
shrouding portion, the first cable shrouding portion and the second cable
shrouding portion define a space to receive the spanning portion of the
flex cable.
11. The shroud assembly of claim 1, further comprising an arm shrouding
portion.
12. The shroud assembly of claim 1, further comprising a flexible
protrusion and at least one locating feature, wherein the locating feature
is configured to mate with a base of the disk drive, and the flexible
protrusion is configured to be deflected by a cover of the disk drive to
apply pressure to the shroud assembly to hold the shroud assembly in
place.
13. A shroud assembly for a disk drive that includes a rotatable disk, a
printed circuit board, a data transfer head, an actuator assembly that
includes an actuator arm and that positions the data transfer head with
respect to the rotatable disk, and a flex cable that interconnects the
actuator assembly and the printed circuit board, the flex cable having a
first end connected to the actuator assembly and a second end connectable
to the printed circuit board, the shroud assembly comprising:
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive and to restrain a transition
portion of the flex cable proximate to the second end, the second surface
configured to receive the second end of the flex cable and to position the
second end for engagement by the printed circuit board;
a cable shrouding portion configured to shield a spanning portion of the
flex cable between the cable mounting portion and the actuator assembly
from airflow generated by the rotation of the rotatable disk; and
an arm shrouding portion connected to the cable mounting portion, the arm
shrouding portion configured to shield an actuator arm from airflow
generated by the rotation of the rotatable disk;
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
14. A shroud assembly for a disk drive that includes a rotatable disk, a
printed circuit board, a data transfer head, an actuator assembly that
includes an actuator arm and that positions the data transfer head with
respect to the rotatable disk, and a flex cable that interconnects the
actuator assembly and the printed circuit board, the flex cable having a
first end connected to the actuator assembly and a second end connectable
to the printed circuit board, the shroud assembly comprising:
a cable shrouding portion configured to shield a spanning portion of the
flex cable between the actuator assembly and the printed circuit board
from airflow generated by the rotation of the rotatable disk; and
an arm shrouding portion integrally formed with the cable shrouding
portion, the arm shrouding portion configured to shield an actuator arm
from airflow generated by the rotation of the rotatable disk;
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
15. A shroud assembly for a disk drive that includes a rotatable disk, a
printed circuit board, a data transfer head, an actuator assembly that
includes an actuator arm and that positions the data transfer head with
respect to the rotatable disk, and a flex cable that interconnects the
actuator assembly and the printed circuit board, the flex cable having a
first end connected to the actuator assembly and a second end connectable
to the printed circuit board, the shroud assembly comprising:
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive a transition portion of the flex
cable proximate to the second end, the second surface configured to
receive the second end of the flex cable and to position the second end
for engagement by the printed circuit board; and
an arm shrouding portion integrally formed with the cable mounting portion,
the arm shrouding portion configured to extend over a portion of the
rotatable disk and to shield an actuator arm from airflow generated by the
rotation of the rotatable disk.
16. A shroud assembly for a disk drive that includes a rotatable disk, a
printed circuit board, a data transfer head, an actuator assembly that
positions the data transfer head with respect to the rotatable disk, and a
flex cable that interconnects the actuator assembly and the printed
circuit board, the flex cable having a first end connected to the actuator
assembly and a second end connectable to the printed circuit board, the
shroud assembly comprising:
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive and to restrain a transition
portion of the flex; cable proximate to the second end, the second surface
configured to receive the second end of the flex cable and to position the
second end for engagement by the printed circuit board; and
a cable shrouding portion integrally formed with the cable mounting
portion, the cable shrouding portion configured to shield a spanning
portion of the flex cable between the cable mounting portion and the
actuator assembly from airflow generated by the rotation of the rotatable
disk;
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
17. A head-stack assembly for a disk drive that includes a rotatable disk
and a printed circuit board, the head-stack assembly comprising:
a preamplifier;
an actuator assembly comprising a body portion, a coil, and an arm, the
body portion having a bore;
a head-gimbal assembly attached to the actuator assembly;
a flex cable that interconnects the actuator assembly and the printed
circuit board, the flex cable having a first end connected to the actuator
assembly and a second end connectable to the printed circuit board; and
a shroud assembly comprising:
a disk shrouding portion;
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive and to restrain a transition
portion of the flex cable proximate to the second end, the second surface
configured to receive the second end of the flex cable and to position the
second end for engagement by the printed circuit board; and
a cable shrouding portion configured to shield a spanning portion of the
flex cable between the cable mounting portion and the actuator assembly
from airflow generated by the rotation of the rotatable disk,
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
18. The head-stack assembly of claim 17, wherein the disk shrouding
portion, the cable mounting portion, and the cable shrouding portion are
integrally formed.
19. The head-stack assembly of claim 17, wherein the cable shrouding
portion is about as long as the disk shrouding portion.
20. The head-stack assembly of claim 17, wherein the first surface of the
cable mounting portion is generally perpendicular to the second surface of
the cable mounting portion.
21. The head-stack assembly of claim 17, wherein the shroud assembly
further comprises a shroud assembly mounting portion that is configured to
be connected to a base of the disk drive.
22. The head-stack assembly of claim 17, wherein the second surface of the
cable mounting portion comprises at least a portion of the shroud assembly
mounting portion.
23. The head-stack assembly of claim 17, wherein the cable shrouding
portion further comprises a first cable shrouding portion and a second
cable shrouding portion, the first cable shrouding portion and the second
cable shrouding portion define a space to receive the spanning portion of
the flex cable.
24. The head-stack assembly of claim 23, wherein the spanning portion of
the flex cable is located between the first cable shrouding portion and
the second cable shrouding portion.
25. The head-stack assembly of claim 23, wherein the shroud assembly
further comprises a flexible protrusion and at least one locating feature,
the locating feature configured to mate with a base of the disk drive, and
the flexible protrusion configured to be deflected by a cover of the disk
drive to apply pressure to the shroud assembly to hold the shroud assembly
in place.
26. A disk drive comprising:
a base;
a printed circuit board connected to the base;
a disk that is rotatable with respect to the base;
a head-stack assembly having an actuator assembly and a flex cable that
interconnects the actuator assembly and the printed circuit board, the
flex cable having a first end connected to the actuator assembly and a
second end connectable to the printed circuit board; and
a shroud assembly mounted on the base, the shroud comprising:
a disk shrouding portion;
a cable mounting portion comprising a first surface and a second surface,
the first surface configured to receive and to restrain a transition
portion of the flex cable proximate to the second end, the second surface
configured to receive the second end of the flex cable and to position the
second end for engagement by the printed circuit board; and
a cable shrouding portion configured to shield a spanning portion of the
flex cable between the cable mounting portion and the actuator assembly
from airflow generated by the rotation of the rotatable disk;
wherein the spanning portion of the flex cable is unrestrained by the cable
shrouding portion when the shroud assembly is applied to the disk drive.
27. The disk drive of claim 26, wherein the disk shrouding portion, the
cable mounting portion, and the cable shrouding portion are integrally
formed.
28. The disk drive of claim 26, wherein the cable shrouding portion is
configured to shield the spanning portion of the flex cable from airflow
that impinges upon a side of the flex cable that faces away from the disk.
29. The disk drive of claim 26, wherein the cable shrouding portion is
located so that the spanning portion of the flex cable is between the
cable shrouding portion and the disk.
30. The disk drive of claim 26, wherein the cable shrouding portion further
comprises a first cable shrouding portion and a second cable shrouding
portion, the first cable shrouding portion and the second cable shrouding
portion define a space to receive the spanning portion of the flex cable.
31. The disk drive of claim 30, wherein the second cable shrouding portion
is configured to shield the spanning portion of the flex cable from
airflow that impinges upon a side of the flex cable that faces toward the
disk.
32. The disk drive of claim 30, wherein the second cable shrouding portion
is located between the first cable shrouding portion and the disk, and the
spanning portion of the flex cable is located between the first cable
shrouding portion and the second cable shrouding portion.
33. The disk drive of claim 26, wherein the shroud assembly is located
downstream of the actuator assembly.
34. The disk drive of claim 26, wherein the shroud assembly further
comprises an arm shrouding portion positioned upstream of the actuator
assembly, the arm shrouding portion configured to shield the actuator arm
from airflow generated by the rotation of the rotatable disk.
35. The disk drive of claim 26, wherein the first surface of the cable
mounting portion is generally parallel to the axis of rotation of the disk
when the shroud assembly is positioned in the disk drive.
36. The disk drive of claim 26, wherein the shroud assembly further
comprises a flexible protrusion and at least one locating feature, the
locating feature configured to mate with the base, and the flexible
protrusion configured to be deflected by the cover to apply pressure to
the shroud assembly to hold the shroud assembly in place.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application relates to a disk drive. More particularly, this
application relates to an improved shroud assembly that shields a flexible
cable from airflow within a case of the enclosure.
2. Description of the Related Art
One type of data storage device used in a computer to permanently store
data is a disk drive. A disk drive includes at least one disk with a
magnetic medium that is mounted on and rotated by a spindle motor. The
disk drive also includes a data transfer head that writes data onto the
magnetic medium and that reads data from the medium in concentric,
generally circular tracks. In most applications, the data transfer head is
extended out over the magnetic medium by an actuator assembly that moves
the head in an arcuate path with respect to the medium. The tracks on the
disk are divided into wedge-shaped regions, called sectors, which are
presented to the data transfer head by the rotation of the disk.
The disk, the head, the actuator assembly, and other components are housed
within a disk drive enclosure to keep contaminants away from the disk and
head. In many designs, the arcuate movement of the actuator assembly is
achieved by a voice-coil motor (VCM), which is controlled by a
servo-system. The data transfer head is connected to a preamplifier on the
actuator assembly. Both the VCM and the preamplifier are connected
electrically to circuitry, e.g., one or more controllers, mounted on a
printed circuit board (PCB). Sometimes a flexible cable, i.e., a "flex
cable," is used to connect the data transfer head and the VCM to the PCB.
A bracket is sometimes used to connect the flex cable mechanically to a
base of the enclosure. As a separate piece, the flex cable bracket adds
material and assembly cost to the disk drive.
The servo-system includes servo data written onto the tracks that can be
read by the data transfer head to give an indication of how close the head
is to the centerline of a track. When the head is over the centerline of
the track and follows it, the head is said to be track-following. When the
head wanders from the centerline of the track, there is said to be track
misregistration, or "TMR." Several factors influence the TMR that the disk
drive will experience. For example, rotation of the disk causes airflow in
the disk drive enclosure. This airflow impinges upon the disk drive
components and causes vibrations in those components that are propagated
to the data transfer head. These vibrations cause the head to move with
respect to the track below the head, and thus increase the TMR. Increased
TMR is not desirable, however, because higher TMR limits track-to-track
spacing (i.e., track pitch) and consequently areal density.
SUMMARY OF THE INVENTION
An object of this invention is to provide a shroud assembly that routes the
flex cable and that also tends to reduce the TMR experienced by a disk
drive.
In one embodiment, the present invention comprises a shroud assembly for a
disk drive that includes a rotatable disk, a printed circuit board, a data
transfer head, an actuator assembly and a flex cable. The actuator
assembly positions the data transfer head with respect to the rotatable
disk. The flex cable interconnects the actuator assembly and the printed
circuit board. The flex cable has a first end connected to the actuator
assembly and a second end connectable to the printed circuit board. The
shroud assembly comprises a disk shrouding portion, a cable mounting
portion, and a cable shrouding portion. The cable mounting portion
includes a first surface and a second surface. The first surface is
configured to receive a transition portion of the flex cable proximate to
the second end. The second surface is configured to receive the second end
of the flex cable and to position the second end for engagement by the
printed circuit board. The cable shrouding portion is configured to shield
a spanning portion of the flex cable between the cable mounting portion
and the actuator assembly from airflow generated by the rotation of the
rotatable disk.
In another embodiment, the present invention comprises a shroud assembly
for a disk drive that includes a rotatable disk, a printed circuit board,
a data transfer head, an actuator assembly and a flex cable. The actuator
assembly positions the data transfer head with respect to the rotatable
disk. The flex cable interconnects the actuator assembly and the printed
circuit board. The flex cable has a first end connected to the actuator
assembly and a second end connectable to the printed circuit board. The
shroud assembly comprises a cable mounting portion, a cable shrouding
portion, and an arm shrouding portion. The cable mounting portion
comprises a first surface and a second surface. The first surface is
configured to receive a transition portion of the flex cable proximate to
the second end. The second surface is configured to receive the second end
of the flex cable and to position the second end for engagement by the
printed circuit board. The cable shrouding portion is configured to shield
a spanning portion of the flex cable between the cable mounting portion
and the actuator assembly from airflow generated by the rotation of the
rotatable disk. The arm shrouding portion is connected to the cable
mounting portion and shields an actuator arm from airflow generated by the
rotation of the rotatable disk.
In another embodiment, the present invention comprises a shroud assembly
for a disk drive that includes a rotatable disk, a printed circuit board,
a data transfer head, an actuator assembly, and a flex cable. The actuator
assembly positions the data transfer head with respect to the rotatable
disk. The flex cable interconnects the actuator assembly and the printed
circuit board. The flex cable has a first end connected to the actuator
assembly and a second end connectable to the printed circuit board. The
shroud assembly comprises a cable shrouding portion and an arm shrouding
portion integrally formed with the cable shrouding portion. The cable
shrouding portion is configured to shield a spanning portion of the flex
cable between the actuator assembly and the printed circuit board from
airflow generated by the rotation of the rotatable disk. The arm shrouding
portion is connected to the cable shrouding portion, and is configured to
shield an actuator arm from airflow generated by the rotation of the
rotatable disk.
In another embodiment, the present invention comprises a shroud assembly
for a disk drive that includes a rotatable disk, a printed circuit board,
a data transfer head, an actuator assembly and a flex cable. The actuator
assembly positions the data transfer head with respect to the rotatable
disk. The flex cable interconnects the actuator assembly and the printed
circuit board. The flex cable has a first end connected to the actuator
assembly and a second end connectable to the printed circuit board. The
shroud assembly comprises a cable mounting portion and an arm shrouding
portion integrally formed with the cable mounting portion. The cable
mounting portion comprises a first surface and a second surface. The first
surface is configured to receive a transition portion of the flex cable
proximate to the second end. The second surface is configured to receive
the second end of the flex cable and to position the second end for
engagement by the printed circuit board. The arm shrouding portion is
integrally formed with the cable mounting portion, and is configured to
shield an actuator arm from airflow generated by the rotation of the
rotatable disk.
In another embodiment, the present invention comprises a shroud assembly
for a disk drive that includes a rotatable disk, a printed circuit board,
a data transfer head, an actuator assembly and a flex cable. The actuator
assembly positions the data transfer head with respect to the rotatable
disk. The flex cable interconnects the actuator assembly and the printed
circuit board. The flex cable has a first end connected to the actuator
assembly and a second end connectable to the printed circuit board. The
shroud assembly comprises a cable mounting portion and a cable shrouding
portion integrally formed with the cable mounting portion. The cable
mounting portion comprises a first surface and a second surface. The first
surface is configured to receive a transition portion of the flex cable
proximate to the second end. The second surface is configured to receive
the second end of the flex cable and to position the second end for
engagement by the printed circuit board. The cable shrouding portion is
configured to shield a spanning portion of the flex cable between the
cable mounting portion and the actuator assembly from airflow generated by
the rotation of the rotatable disk.
In another embodiment, the present invention comprises a head-stack
assembly for a disk drive that includes a rotatable disk and a printed
circuit board. The head-stack assembly comprises a preamplifier, an
actuator assembly, a head-gimbal assembly, a flex cable, and a shroud
assembly. The actuator assembly includes a body portion, a coil, and an
arm. The body portion of the actuator assembly has a bore. The head-gimbal
assembly is attached to the actuator assembly. The flex cable
interconnects the actuator assembly and the printed circuit board. The
flex cable has a first end that is connected to the actuator assembly and
a second end that is connectable to the printed circuit board. The shroud
assembly comprises a disk shrouding portion, a cable mounting portion, and
a cable shrouding portion. The cable mounting portion includes a first
surface and a second surface. The first surface is configured to receive a
transition portion of the flex cable proximate to the second end. The
second surface is configured to receive the second end of the flex cable
and to position the second end for engagement by the printed circuit
board. The cable shrouding portion is configured to shield a spanning
portion of the flex cable between the cable mounting portion and the
actuator assembly from airflow generated by the rotation of the rotatable
disk.
In another embodiment, the present invention comprises a disk drive that
has a base, a printed circuit board connected to the base, and a disk that
is rotatable with respect to the base. The disk drive also has a
head-stack assembly and a shroud assembly. The head-stack assembly has an
actuator assembly and a flex cable that interconnects the actuator
assembly and the printed circuit board. The flex cable has a first end
that is connected to the actuator assembly and a second end that is
connectable to the printed circuit board. The shroud assembly is mounted
on the base and has a disk shrouding portion, a cable mounting portion,
and a cable shrouding portion. The cable mounting portion includes a first
surface and a second surface. The first surface is configured to receive a
transition portion of the flex cable proximate to the second end. The
second surface is configured to receive the second end of the flex cable
and to position the second end for engagement by the printed circuit
board. The cable shrouding portion is configured to shield a spanning
portion of the flex cable between the cable mounting portion and the
actuator assembly from airflow generated by the rotation of the rotatable
disk.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding
of the present invention and are incorporated in and constitute a part of
this specification. The drawings illustrate embodiments of the present
invention and together with the description serve to explain the
principles of the invention.
FIG. 1 is a perspective view of a disk drive with a printed circuit board
removed and a cover partially broken away to illustrate internal
components.
FIG. 2 is a perspective view of a head-disk assembly of the disk drive of
FIG. 1 illustrating airflow patterns generated during the operation
thereof
FIG. 3 is a bottom perspective view of one embodiment of a shroud assembly
illustrated in FIG. 2 and a portion of a flex cable.
FIG. 4 is a top perspective view of another embodiment of a shroud
assembly.
FIG. 5 is a perspective view of a head-disk assembly that includes another
embodiment of a shroud assembly.
FIG. 6 is a perspective view of a head-disk assembly drive that includes
another embodiment of a shroud assembly having an arm shroud.
FIG. 7 is a top perspective view of the shroud assembly illustrated in FIG.
6.
FIG. 8 is a bottom perspective view of the shroud assembly illustrated in
FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view of a disk drive 10. The disk drive 10 includes
a head-disk assembly (HDA) 14 and a printed circuit board 18. The HDA 14
comprises an enclosure 22 that includes a cover 26 and a base 30. The
printed circuit board 18 is connectable to the base 30, but is shown
removed therefrom in FIG. 1 for illustration. The HDA 14 also includes at
least one disk 34, a spindle motor assembly 38, a head-stack assembly
(HSA) 42, and a permanent magnet assembly 44. The disk 34 is mounted on
the spindle motor assembly 38 and is rotatable thereby with respect to the
base 30. The disk drive 10 of FIGS. 1, 2 and 5 has three disks 34. One
skilled in the art will recognize that the shroud assembly embodiments
described herein can be used in a disk drive having other numbers of disks
34. For example, FIG. 6 illustrates one embodiment of the shroud assembly
described herein incorporated into a disk drive having one disk.
Each disk 34 has at least one surface that has a magnetic medium deposited
thereon. Magnetic transitions representing data are written onto and read
from the magnetic medium in a known manner.
The HSA 42 includes an actuator assembly 46, a preamplifier (not shown), a
head-gimbal assembly (HGA) 54, a flex cable 58, and one embodiment of a
shroud assembly 62. The actuator assembly 46 includes a pivot 64, body
portion 66, a coil 70, and an arm 74. The body portion 66 has a bore 78
extending from a first side to a second side. The pivot 64 is located in
the bore 78 and attached to the base 30 to provide for pivotal motion of
the body portion 66 with respect to the base 30.
The arm 74 extends from a first end proximate the body portion 66 to a
second end to which the HGA 54 is attached. The HGA 54 includes a
suspension 86, a slider 90 and a conductor 94. The slider 90 includes an
element for writing data to the magnetic medium of the disk 34 and an
element for reading data from the magnetic medium of the disk. Together,
the slider 90 and the elements contained thereon constitute a data
transfer head. One skilled in the art will recognize that the read element
and the write element can be a single element or can be separate elements
on the slider 90. Although described herein with respect to a read/write
system, the shroud assembly described herein could also improve track
following performance in read-only application, i.e., one having a slider
with a read element only. The conductor 94 provides an electrical
connection between the elements of the slider 90 and the preamplifier.
In one embodiment, the coil 70 of the actuator assembly 46 extends from the
body portion 66 on a side opposite the arm 74. The coil 70 interacts with
a permanent magnet located in the permanent magnet assembly 44 when
current is passed through the coil to cause the body portion 66 and,
ultimately, the slider 90 to rotate about the pivot 64 and to be
selectively positioned over the magnetic medium of the disk 34. Control of
the positioning is provided by a conventional servo system.
The flex cable 58 is generally a very thin, ribbon-like flexible cable
having two sides. As shown in FIGS. 1 and 3, the flex cable 58 has a first
end 96, a second end 98, a spanning portion 100 and a transition portion
101. The first end 96 of the flex cable 58 is the end that is connected to
the preamplifier. The second end 98 of the flex cable 58 is the end
opposite the first end 96 and is connectable to the printed circuit board
18. A spanning portion 100 of the flex cable 58, discussed in more detail
below, is a portion of the flex cable 58 proximate the first end 94 in one
embodiment. More generally, the spanning portion 100 is any portion of the
flex cable 58 that has both of its sides exposed to the atmosphere within
the enclosure 22. The transition portion 101 of the flex cable 58, in one
embodiment, is the portion between the vertically oriented spanning
portion 100 and the horizontally oriented second end 98.
The flex cable 58 contains electrical conductors that electrically connect
components on the actuator assembly 46, e.g., the preamplifier and the
coil 70, to the circuits mounted on the printed circuit board 18, e.g., a
read/write channel and a servo controller.
The spindle motor assembly 38 is also electrically connected to the printed
circuit board 18, e.g., to a spindle motor controller. The spindle motor
controller controls the rotation of the rotatable shaft and hub of the
spindle motor assembly 38 and the disk 34 attached thereto. When
operating, the disk 34 is rotated at a substantially constant angular
velocity .omega..
The rotation of the disk 34 creates airflow within the enclosure 22. The
direction and path of a portion of this airflow is shown as the dashed
lines "A," "B," "C," "D," "E," "F," and "G" in FIG. 2. Airflow in the
enclosure 22 generally follows the rotational movement of the disk 34 as
indicated at "A." However, just upstream of the actuator assembly 46, at a
first gap 102 between the base 30 and the permanent magnet assembly 44, a
portion of the airflow "B" moves away from the disk 34 and around the
permanent magnet assembly 44. Another portion of the airflow "C" continues
to follow the rotational movement of the disk 34.
The airflow "B" continues through a second gap 106 between the base 30 and
the permanent magnet assembly 44. A portion "D" of the airflow "B" is
directed toward a flex cable routing area 110. Another portion "E" of the
airflow "B" is directed around the shroud assembly 62 and back toward the
disk 34 through a third gap 114 defined by the base 30 and the shroud
assembly 62. FIG. 2 shows that a cable shrouding portion 118 shields the
spanning portion 100, as discussed below.
The airflow "C" in FIG. 2, continues to follow the disk 34 past the first
gap 102 until it reaches the vicinity of the actuator arm 74. A portion
"F" of the airflow "C" continues past the actuator arm 74 and then moves
off of the surface of the disk 34 toward the side of the spanning portion
100 of the flex cable 58 that faces toward the disk 34. Another portion
"G" of the airflow "C" continues to follow the rotational movement of the
disk 34 (see FIG. 2). Another portion (not shown) of the airflow impinges
on the actuator arm 74.
Applicants have discovered that in prior designs, the airflow "D" impinges
upon the flex cable 58 in the flex cable routing area 110, e.g., on the
side of the spanning portion 100 of the flex cable 58 that faces away from
the disk 34. Furthermore, applicants have discovered that in prior designs
the airflow "F" impinges upon the side of the flex cable 58 that faced
toward the disk 34. As discussed above, the impact of such airflow on the
flex cable 58 causes vibration of the flex cable, which increases the TMR
in the prior designs. Accordingly, one embodiment of the present invention
includes a shroud assembly 62 configured to shield the spanning portion
100 of the flex cable 58 from at least a portion of one of the airflow "D"
and the airflow "F."
FIG. 3 illustrates one embodiment of the shroud assembly 62 in more detail.
The shroud assembly 62 includes a cable mounting portion 116, a cable
shrouding portion 118, and a disk shrouding portion 130. In one
embodiment, the cable mounting portion 116 includes a first surface 124
and a second surface 128. The second surface 128 receives the second end
98 of the flex cable 58. The second end 98 of the flex cable 58 is the end
that is connectable to the printed circuit board 18. The second surface
128 positions the second end 98 for connection to the printed circuit
board 18 and also tends to hold the second end 98 of the flex cable 58 in
place. The first surface 124 receives a portion of the flex cable 58
proximate to the second end 98, e.g., the transition portion 101. In one
embodiment, the transition portion 101 is threaded through three retaining
clips 126 to secure it in place. The retaining clips 126 preferably are
integrally formed portions of the shroud assembly 62. The retaining clips
126 are configured to make the assembly of the HSA 42 simple. The
transition portion 101 of the flex cable 58 could be secured to the shroud
assembly 62 in other suitable ways, as will be recognized by one skilled
in the art. For example, other numbers of retaining clips, adhesives,
other mechanical fasteners, and other fastening devices could be used.
In one embodiment, the first surface 124 of the cable mounting portion 116
is generally perpendicular to the second surface 128 of the cable mounting
portion 116. The first surface 124 and the second surface 128 could be
arranged in other ways within the scope of the invention claimed herein.
For example, in one variation the first surface 124 and the second surface
128 may advantageously be disposed at non-perpendicular angles with
respect to each other. Or, the first surface 124 and the second surface
128 may advantageously be combined into one continuously curved surface.
Many other configurations are also possible, e.g., the shroud assembly 62
may advantageously include a third surface between the first surface 124
and the second surface 128.
The shroud assembly 62 thus secures the flex cable 58 so that it does not
move inside the enclosure 22 and also routes the flex cable so that the
second end 98, which is configured to be connected to the printed circuit
board 18, is properly positioned for such connection.
In one embodiment, the cable shrouding portion 118 further comprises a
distal end 119 and a mounted end 120. A length is defined as distance
between the distal end 119 and the mounted end 120. The cable shrouding
portion 118 also comprises, in this embodiment, a first edge 121 proximate
the cable mounting portion 116, and a second edge 122 opposite the first
edge 121. A width is defined as the perpendicular distance between the
first edge 121 and the second edge 122. In one embodiment, the length of
the cable shrouding portion 118 is about twice the width of the cable
shrouding portion 118. In another embodiment, the length of the cable
shrouding portion 118 is about equal to the length of the disk shrouding
portion 130.
The cable shrouding portion 118 can be formed in any number of shapes.
FIGS. 2 and 3 illustrate one embodiment where the cable shrouding portion
118 forms an arc. In this embodiment, the inside surface of the arc is
located on a side of the shroud assembly 62 that faces the disk 34 when
the shroud assembly is positioned in the disk drive 10. In another
embodiment, the cable shrouding portion 118 forms an arc that has an inner
surface that faces the opposite direction (i.e., away from the disk 34
when the shroud assembly 62 is in the disk drive 10). This oppositely
facing shrouding portion arc is illustrated in FIG. 5. In another
embodiment, the cable shrouding portion 118 extends along a generally
straight line from an edge of the first surface 124 toward the permanent
magnet assembly 44 when the shroud assembly is inserted into the disk
drive 10. Many other shapes are possible, as should be recognized by one
skilled in the art.
The configuration of the cable shrouding portion 118 may also take into
account the presence and location of any structure located in or on the
enclosure proximate the position of the cable shrouding portion 118. Such
structure could be a raised portion of the base 30 or a lowered portion of
the cover 26, for example. Where such structures are present proximate the
cable shrouding portion 118, the cable shrouding portion can be shaped to
avoid them.
The cable shrouding portion 118 of the shroud assembly 62 shields the
spanning portion 100 of the flex cable 58 from airflow generated by the
rotation of the disk 34, e.g., the airflow shown in FIG. 2. As discussed
above, the spanning portion 100 is the portion of the flex cable 58
between the first end 96 and the transition portion 101 secured at the
first surface 124. As discussed above in connection with FIG. 2, the
impact of the airflow on the spanning portion 100 of the flex cable 58 can
increase the TMR of the disk drive. When the shroud assembly 62 is
positioned in the disk drive 10, the cable shrouding portion 118 is
located between the spanning portion 100 and the direction of the airflow
"D," and therefore protects the spanning portion 100 from such airflow.
The cable shrouding portion 118 thereby tends to reduce the TMR of the
disk drive 10.
In another embodiment, the cable shrouding portion 118 is located and
configured so that when the shroud assembly 62 is positioned in the disk
drive 10, the cable shrouding portion 118 is between the spanning portion
100 and the disk 34. In this position, the cable shrouding portion 118
shields the spanning portion 100 from the airflow "D."
The disk shrouding portion 130 of the shroud assembly 62 is provided with a
generally smooth, generally cylindrical curved surface. The cylindrical
curved surface of the disk shrouding portion 130 and the outer
circumference of the disk 34 are preferably concentric. A clearance is
provided between the disk shrouding portion 130 and the disk 34 so that
the disk shrouding portion 130 does not interfere with the rotation of the
disk 34. However, the disk shrouding portion 130 is placed close enough to
the disk 34 to reduce disk flutter and to protect the suspension 86 from
the airflow within the enclosure 22. In one embodiment, the disk shrouding
portion 130 is formed as a separate extension of a disk shroud 131 of the
base 30. In certain embodiments discussed herein, a shroud assembly is
provided without a disk shrouding portion 130.
In one embodiment, the shroud assembly 62 further comprises a shroud
assembly mounting portion 132. The shroud assembly mounting portion 132 is
configured to be mechanically connected to the base 30 of the disk drive
10. In one embodiment, the shroud assembly mounting portion 132 includes
one or more through-holes 136 that are sized to receive suitable
fasteners, such as screws (see FIG. 3). Other fastening techniques are
also possible. For example one or more locating features 133 could be
located on the cable mounting portion 116. As discussed below in
connection with FIG. 4, the locating features 133 advantageously are used
when pressure-mounting any of the shroud assembly embodiments described
herein. One skilled in the art will recognize that the shroud assembly
embodiments described herein could also be mounted in other ways, e.g., by
using an adhesive. In one embodiment, the second surface 128 of the cable
mounting portion 116 forms at least a portion of the shroud assembly
mounting portion 132.
FIG. 4 illustrates another embodiment of a shroud assembly 150, that is
similar to the shroud assembly 62, except as detailed below. The shroud
assembly 150 includes a first cable shrouding portion 154 and a second
cable shrouding portion 158. The first cable shrouding portion 154 and the
second cable shrouding portion 158 define a space 160 to receive the
spanning portion 100 of the flex cable 58. The first cable shrouding
portion 154 is similar to the cable shrouding portion 118. The second
cable shrouding portion 158 may have the same shape as the first cable
shrouding portion 154, may be a mirror image thereof, or may have a
different shape. As discussed above in connection with the cable shrouding
portion 118, the first cable shrouding portion 154 protects the flex cable
58 from the airflow "D" that is directed toward the side of the spanning
portion 100 that faces away from the disk 34. The second cable shrouding
portion 158 protects the flex cable 58 from the airflow "F" that is
directed toward the side of the spanning portion 100 that faces toward the
disk 34. In this configuration, both sides of the spanning portion 100 of
the flex cable 58 are shrouded from airflow, further reducing vibration of
the flex cable 58 and thereby further reducing TMR of the disk drive 10.
The shroud assembly 150 also advantageously includes a flexible protrusion
135 and a cable mounting portion 137 that includes the locating features
133. During assembly of the disk drive 10, the shroud assembly 150 is
mounted in the enclosure 22. To secure the shroud assembly 150 in place,
the locating features 133, which are shown as short protrusions in FIG. 3,
are inserted into corresponding holes or depressions in the base 30. When
the shroud assembly 150 is positioned on the base 30, the height of the
top of the flexible protrusion 135 is higher than the top of the base 30.
Accordingly, the flexible protrusions 135 is deflected when the cover 26
is mounted onto the top of the base 30. The deflection of the flexible
protrusion 135 causes a reaction force to be applied by the cover to the
shroud assembly 150. This reaction force holds the shroud assembly 150 in
place in the enclosure 22.
FIG. 5 illustrates another embodiment of a shroud assembly 170 positioned
within a HDA. The shroud assembly 170 is similar to the shroud assembly
62, except as detailed below. The shroud assembly 170 has a cable mounting
portion 174 and a cable shrouding portion 176. The cable mounting portion
174 has a first surface 178 and a second surface 182. The first surface
178 receives a transition portion of the flex cable 58. Clips similar to
the clips 126 or other suitable fasteners are provided on the first
surface 178 to secure the transition portion 101 of the flex cable 58. The
first surface 178 of the shroud assembly 170 also functions as a disk
shrouding portion, i.e., it is placed close enough to the disk 34 to
reduce disk flutter and to protect the suspension 86 from the airflow
within the enclosure 22. The second surface 182 routes the flex cable 58
so that the second end 98 of the flex cable is positioned to be connected
to the printed circuit board 18. FIG. 5 illustrates that the routing of
the flex cable 58 for the shroud assembly 174 is different from the
routing of the flex cable 58 for the shroud assembly 62. The flex cable 58
is positioned to be engaged by the printed circuit board 18 at a position
much closer to the disk 34 and at an angle with respect to the
longitudinal axis of the base 30. This provides a shroud assembly that is
generally smaller, and that generally reduces cost. The cable shrouding
portion 176 of the shroud assembly 170 shields the spanning portion 100 of
the flex cable 58 in the flex cable routing area 110, as discussed above.
FIGS. 6-8 illustrates another embodiment of a shroud assembly 190. FIG. 6
illustrates the shroud assembly 190 incorporated into an HDA 192. The HDA
192 is similar to the HDA 14, except that it has only one disk 34.
However, as discussed above, one skilled in the art will recognize that
the shroud assembly 190 could be used in a disk drive having more than one
disk 34. FIGS. 6-8 illustrate two approaches to mounting the shroud
assembly 190. FIG. 6 shows a screw-mount type, as discussed above. FIGS. 7
and 8 illustrate a pressure-mount type, as discussed above in connection
with FIG. 4.
The shroud assembly 190 is similar to the shroud assembly 62, except as
detailed below. The shroud assembly 190 comprises an extending portion 194
and an arm shrouding portion 198. In one embodiment, the extending portion
194 projects out from the disk shrouding portion 130 of the shroud
assembly 190 at approximately a right angle. The extending portion 194 is
sized and configured to extend from the cable routing area 110 of the HDA
192 to a location over the disk 34. In one embodiment, the extending
portion 194 extends almost to the outer circumference of the hub of the
spindle motor assembly 38, with a small gap to provide clearance for the
hub. The extending portion 194 also extends laterally from the flex cable
routing area 110 toward an opposite side 200 of the base 30. In one
embodiment, the extending portion 194 extends all the way to the opposite
side 200 of the base 30 and is supported by a shoulder area 202 of the
opposite side 200. The arm shrouding portion 198 of the shroud assembly
190 extends from a side of the extending portion 194 that faces the disk
34, i.e., the underside of the extending portion 194. The position of the
arm shrouding portion 198 is such that when the shroud assembly 190 is
positioned in the HDA 192, the arm shrouding portion 198 is located
upstream of the actuator arm 74 of the HSA 42. As used herein, "upstream"
means located between the point of reference and the source of airflow
(e.g., the actuator arm 74). In the illustrated embodiment, an "upstream"
location is one that is clockwise of a given location when viewed from the
side of the HDA 192 that faces the cover (See FIG. 1). In this position,
the arm shrouding portion 198 protects the arm 74 from the airflow "C" and
thereby reduces vibrations that would otherwise be induced in the arm 74
by the airflow. By reducing the vibrations that would otherwise be induced
in the arm 74, the arm shrouding portion 198 reduces TMR of the HDA 192.
Although the preferred embodiment of the shroud assembly 190 includes the
cable mounting portion 116, the cable shrouding portion 118, the disk
shrouding portion 130, and the arm shrouding portion 198, the invention
claimed below can be carried out with fewer than all of these components.
For example one embodiment includes the cable mounting portion 116, the
cable shrouding portion 118, and the arm shrouding portion 198, which are
all integrally formed. Another integrally formed embodiment includes the
cable shrouding portion 118 and the arm shrouding portion 198. Yet another
integrally formed embodiment includes the cable mounting portion 116 and
the arm shrouding portion 198.
*
