Title: Spring disk clamp utilizing wedged retaining ring
Abstract: A spring disk clamp is provided for securing one or more data storage disks to a disk drive without the need for screws. The disk clamp incorporates an angled surface defining the central opening of the clamp which is positioned adjacent a sloping surface of the hub. An external axial load applied to the clamp deflects the clamp, and allows a retaining member to be wedged between the clamp and the hub. Stabilizing features such as O-rings and the like are also eliminated as the clamp of the invention provides both radial and axial stabilization to the disk pack in its mounting to the hub.
Patent Number: 6,967,814 Issued on 11/22/2005 to Chessman, et al.
| Inventors:
|
Chessman; Herbert Ross (Erie, CO);
Mischo; Paul D. (Longmont, CO)
|
| Assignee:
|
Maxtor Corporation (Longmont, CO)
|
| Appl. No.:
|
626812 |
| Filed:
|
July 23, 2003 |
| Current U.S. Class: |
360/99.12; 360/98.08 |
| Intern'l Class: |
G11B 017/02.8 |
| Field of Search: |
360/9912,980.8,99
|
References Cited [Referenced By]
U.S. Patent Documents
| 5270999 | Dec., 1993 | Chessman et al.
| |
| 5274517 | Dec., 1993 | Chen.
| |
| 5333080 | Jul., 1994 | Ridinger et al.
| |
| 5528434 | Jun., 1996 | Bronshvatch et al.
| |
| 5548457 | Aug., 1996 | Brooks et al.
| |
| 5555144 | Sep., 1996 | Wood et al.
| |
| 5731928 | Mar., 1998 | Jabbari et al.
| |
| 5790345 | Aug., 1998 | Alt.
| |
| 5940244 | Aug., 1999 | Canlas et al.
| |
| 6172844 | Jan., 2001 | Luo et al.
| |
| 6462902 | Oct., 2002 | Luo et al.
| |
| 6550328 | Apr., 2003 | Horning et al.
| |
| 6563668 | May., 2003 | Suwito.
| |
| 6816338 | Nov., 2004 | Suwito.
| |
Primary Examiner: Tupper; Robert S.
Attorney, Agent or Firm: Sheridan Ross P.C.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a divisional application of and claims priority from
U.S. patent application Ser. No. 09/905,385, filed Jul. 12, 2001 now U.S. Pat.
No. 6,624,968, entitled "SPRING DISK CLAMP UTILIZING WEDGED RETAINING RING", the
entire disclosure of which is incorporated herein by this reference.
Priority is claimed from U.S. Provisional Patent Application No. 60/217,995
filed on Jul. 13, 2000, and entitled "SPRING DISK CLAMP UTILIZING WEDGED RETAINING
RING" and further identified as the disclosure of which is incorporated herein
by reference in its entirety.
Claims
1. An assembly for securing one or more disks to a hub of a disk drive, said
assembly comprising:
a spindle hub having a circumferential groove formed thereon, said groove being
defined by at least one sloping surface;
a disk clamp mounted over said spindle hub, said disk clamp including a central
opening defined by at least one angled surface which lies adjacent said at least
one sloping surface when said disk clamp is mounted over said spindle hub, said
disk clamp further including a lower surface, an upper surface, a peripheral flange
integral with said disk clamp and extending radially outward and downward from
said lower surface, and a circumferential groove formed on said upper surface; and
a retaining member inserted in a gap between said at least one sloping surface
and said at least one angled surface.
2. An assembly, as claimed in claim 1, further including:
a balance ring mounted in said circumferential groove.
3. An assembly, as claimed in claim 1, wherein:
said retaining member includes a plurality of arc sections selectively spaced
from one another in said gap.
4. An assembly for securing one or more disks to a hub of a disk drive, said
assembly comprising:
a spindle hub having a circumferential groove formed thereon, said groove being
defined by at least one sloping surface;
a disk clamp mounted over said spindle hub, said disk clamp including a central
opening defined by at least one angled surface which lies adjacent to said at least
one sloping surface when said disk clamp is mounted over said spindle hub, said
disk clamp further having an annular body portion including upper and lower surfaces,
a peripheral edge, means spaced radially inward from said peripheral edge for allowing
said annular body portion to deflect in response to an axial load placed on said
annular body portion, and a circumferential groove formed on said upper surface; and
a retaining member inserted in a gap between said at least one sloping surface
and said at least one angled surface.
5. An assembly, as claimed in claim 4, further including:
a balance ring mounted in said circumferential groove.
6. A method of securing one or more data disks to a hub of a disk drive, said
method comprising the steps of:
providing a disk clamp having a peripheral flange, and a central opening defined
by at least one angled surface;
providing a spindle hub having a circumferential groove formed thereon, said
circumferential groove being defined by at least one sloping surface;
mounting the clamp over the hub so that said angled surface of said clamp lies
adjacent said sloping surface of said hub;
applying an axial load to said disk clamp;
deflecting said disk clamp in response to said axial load causing said angled
surface to displace away from said sloping surface;
inserting a retaining member between said angled surface and said sloping surface; and
releasing the axial load resulting in said angled surface moving back toward
said sloping surface thereby wedging said retaining member between said angled
surface and said sloping surface.
7. A method, as claimed in claim 6, wherein:
said angled surface and said sloping surface extend substantially parallel to
one another.
8. A method, as claimed in claim 6, wherein:
said angled surface and said sloping surface extend at an angle to one another
between about zero degrees and fifteen degrees.
9. A method, as claimed in claim 6, wherein:
the retaining member is of a desired cross-sectional area prior to said inserting
step to selectively adjust an amount of force supplied by the disk clamp to secure
the one or more data disks.
10. An assembly, as claimed in claim 4, wherein:
said retaining member includes a plurality of arc sections selectively spaced
from one another in said gap.
11. A method of securing one or more data disks to a hub of a disk drive without
the use of securing screws, said method comprising the steps of:
providing a disk clamp of unitary construction without screw holes, and a central
opening defined by at least an angled surface, said disk clamp further including
a lower peripheral flange extending radially outward and downward from said disk clamp;
providing a spindle hub having a circumferential groove formed thereon;
mounting the clamp over the hub;
applying an axial load to the disk clamp;
deflecting the disk clamp in response to the axial load;
inserting a retaining member in a gap between the angled surface and the circumferential groove;
releasing the axial load resulting in partial return of the disk clamp from its
deflected state thereby wedging the retaining member between the disk clamp and
the hub.
12. A method, as claimed in claim 11, wherein:
said circumferential groove of the spindle hub is defined by at least one sloping
surface, wherein said release of the axial load results in said angled surface
moving back towards said sloping surface thereby wedging the retaining member between
the angled surface and the sloping surface.
13. A method, as claimed in claim 12, wherein:
said angled surface and said sloping surface extend substantially parallel to
one another.
14. A method, as claimed in claim 12, wherein:
said angled surface and said sloping surface extend at an angle to one another
between about 0° and 15°.
15. A method, as claimed in claim 11, further including the step of:
providing the retaining member of a desired cross-sectional area prior to said
inserting step to selectively adjust a magnitude of force sup plied by the disk
clamp to secure the one or more data disks.
Description
FIELD OF THE INVENTION
This invention relates to disk drive systems, and more particularly, to an apparatus
and method of securing one or more data storage disks to a hub of a spindle motor
used in a disk drive.
BACKGROUND OF THE INVENTION
Disk drive data storage systems typically include one or more data storage disks
mounted to a spindle hub, and a spindle motor drives the spindle hub which rotates
the disks at high RPMs. A disk clamp assembly secures the disks to the hub.
Data disks have a central bore or opening that receives the spindle hub. A common
type of disk clamp assembly includes an annular or disk-shaped disk clamp, and
a number of screws that secure the clamp to the hub. One or more disks positioned
below the clamp are secured to the hub. In addition, spacers may be placed on both
sides of each disk. For example, in a disk drive with a single data disk, the arrangement
could include in series, a clamp, a spacer adjacent the clamp, a disk, a spacer
on the opposite side of the disk, and then the hub. For some disk clamp assemblies,
a top data disk may directly contact the disk clamp without the use of a spacer.
The disks and spacers are often referred to as a disk pack.
Examples of references disclosing clamps utilizing securing screws include
the U.S. Pat. Nos. 5,274,517; 5,333,080, 5,528,434, and 5,790,345.
Certain disadvantages arise by using screws to secure the clamp to the hub.
One distinct disadvantage is that the screws transmit uneven and irregular radially
and axially directed forces to the data disk, thus resulting in surface irregularities
on the disk. Any distortion or surface irregularities of the disk read/write surface
may result in poor head transducer flight characteristics. Another disadvantage
is that use of screws contributes to disk contamination. Particle generation occurs
when the screws are driven for attaching the clamp.
Another type of disk clamp exists which does not require the use of screws
to secure the clamp to the hub. Presumably, these types of clamps help to reduce
undesirable radial or axial loading and also help to reduce contamination. One
example of a clamping device which does not require the use of screws to secure
a clamp to the hub includes the device disclosed in the U.S. Pat. No. 5,270,999.
The disk clamp disclosed in this references has a flat lower surface which directly
contacts the data disk. The central opening of the clamp includes an inner conical
surface. The upper end of the hub includes a groove having a complementary conical
surface. When the clamp is mounted over the hub, a uniform circumferential gap
exists between the conical surfaces. A clip or spring is placed in the gap between
the conical surfaces. When the spring is in place, the clamp resists axial force
that may act to disengage the disk from the hub. In addition to the clip or spring,
an O-ring is also used to stabilize the disk with respect to the hub. The clamp
disclosed in the '999 patent provides very little axial force to secure the disk
or disks to the hub. Thus, the O-ring must be used to help prevent radial movement
of the disk with respect to the hub. There is always some small gap between the
inner edge of the disk defining the central opening and the outer surface of the
hub. This gap can allow radial movement of the disk with respect to the hub if
no force is provided to prevent such radial movement.
While the foregoing references may be adequate for their intended purposes,
the clamp of the present invention further simplifies the overall disk clamp and
hub arrangement, thus minimizing the cost of fabrication and assembly, reducing
the likelihood of malfunction in the disk drive system, and providing effective
and consistent performance.
SUMMARY OF THE INVENTION
In accordance with the preferred embodiment of the present invention, an apparatus
in the form of a disk clamp, and a method for securing one or more data storage
disks to a hub of a disk drive is provided. The disk clamp eliminates the need
for using screws to secure the clamp to the hub. In use, the clamp provides an
axial force upon the disk pack which prevents the disk(s) from both axial and radial
displacement with respect to the hub. The axial force keeps the disk or disks from
slipping relative to the hub during rotation, and during events such as high shock
loads impacting the disk drive. The disk clamp is deflected by an external axial
load, and then a retaining member such as a wire ring or multiple sections of wire
arcs are inserted between an angled surface defining the central opening of the
clamp and a corresponding sloping surface defining a concentric groove formed on
the hub. Since screws are not used to set the clamp, uneven loads causing undesirable
radial and axial forces upon the disk or disks are eliminated, thus reducing disk
distortion in the direction of read/write flight. Furthermore, O-rings or other
stabilizing structures are not required to stabilize the connection between the
disk and the hub because of the axial force which is provided by the clamp.
The disk clamp includes a lower peripheral flange which contacts the underlying
spacer or disk. When the external axial load is applied to set the clamp, the disk
clamp itself acts as a spring in that it deflects downward in response to the applied
axial load. After the retaining member is placed in the gap between the groove
on the hub and the angled surface of the clamp, the axial load is removed which
enables the disk clamp to spring back to its undeflected state; however, the retaining
member prevents full return resulting in the retaining member being wedged between
the clamp and the hub. A peripheral groove may be formed on the upper surface of
the clamp for receiving a balance ring. The balance ring is sized and positioned
to spin balance the disk pack.
Additional advantages will become apparent from a review of the below-described
drawings, taken in conjunction with the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a hub and disk assembly of a disk
drive, including the disk clamp of the present invention;
FIG. 2 is an enlarged fragmentary perspective view of the disk clamp;
FIG. 3 is a vertical section illustrating the manner in which the clamp secures
the disk and associated spacers; and
FIG. 4 is a greatly enlarged section of FIG. 3.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to the drawings and specifically to FIG. 1, a disk drive
includes a housing H, a chamber C formed in the housing for receiving one or more
data disks D including one or more corresponding spacers S. FIG. 1 illustrates
a single disk D disposed between a pair of spacers S. If no upper spacer were used,
the disk clamp would directly contact the disk D. However, it shall be understood
that the clamp of the present invention is usable with single or multiple data
disks D depending upon the configuration the disk pack.
Now also referring to FIG. 3, when the disk drive is assembled, the lower spacer
S
1 rests upon a flange
11 of the hub
10. The disk D rests
on the lower spacer S
1, and an upper spacer S
2 is placed
on top of the disk D. The spring disk clamp
12 contacts the upper surface
of the upper spacer S
2. If an upper spacer is not used, the disk clamp
would directly contact the disk D. When an external axial load is applied to the
clamp
12, retaining ring
14 is inserted into the gap between the
concentric groove formed on the upper extension
15 of the hub
10
and the inner surface defining the central opening of the clamp
12, as further
discussed below. A balance ring
16 is inserted within a peripheral groove
34 formed on the upper surface of the clamp
12.
Now referring to FIG. 2, the specific construction of the spring clamp
12
is best seen. Clamp
12 includes an annular body portion
20. A lower
peripheral flange
22 is integral with the body portion
20 and extends
radially outward and downward from the lower surface
26 of the clamp
12.
The lower peripheral flange
22 terminates at the external peripheral edge
23 of the clamp. The peripheral flange
22 is illustrated as having
a flat lower surface; however, as desired, the lower surface of the peripheral
flange can be modified to include either a flat or rounded shape. The central opening
of the clamp
12 is defined by an inner perpendicular edge
28, and
a chamfered or conical angled surface
30. As shown, the most upper portion
of the angled surface
30 communicates with the upper surface
32 of
the clamp. Finally, the clamp
12 includes the upper concentric groove
34
formed on the upper surface thereof. Groove
34 is located adjacent the peripheral
edge
23. An arcuate-shaped pocket
36 of the groove
34 receives
the balance ring
16 therein.
Now referring to FIGS. 3 and 4, the spindle hub
10 includes an annular
surface
50 which is provided at a height so that a definable gap exists
between it and the lower surface
26 of the clamp
12. Because the
peripheral flange
22 does not completely cover the upper surface
51
of the upper spacer S
2, the gap extends to the most inner concentric
portion
52 of the flange
22.
The upper extension
15 of the hub
10 includes the circumferential
groove formed thereon. This groove is defined by one or more shaped surfaces and
specifically includes sloping surface
54 and adjacent arcuate surface
56.
The sloping surface
54 communicates with a planar annular upper surface
58 of the hub extension
15. The sloping surface
54 and upper
surface
58 can be described as forming an annular lip or flange
60.
Once the disk clamp
12 is placed over the hub
10, the axial load
is applied on upper surface
32 to set the clamp. In response to the axial
loading, the annular body portion
20 deflects downward, thus increasing
the gap between surfaces
30 and
54, and narrowing the gap between
lower surface
26 and upper surface
50. The clamp primary deflects
along the concentric narrowed portion
62 defined between the concentric
portion
52 and the inner edge
64 of the groove
34. Therefore,
this narrowed portion
62 provides a means for allowing the clamp to deflect
in response to a load. When the clamp is deflected, the retaining ring
14
can be positioned between sloping surface
54 and angled surface
30.
When the axial load is released, the clamp springs back to achieve its undeflected
state; however, the retaining ring
14 prevents full return resulting in
the retaining member being wedged between the clamp and the hub. The retaining
ring
14 can be sized to accommodate the desired magnitude of the securing
force applied for securing the disk pack. Use of a retaining ring
14 having
a larger cross sectional area would result in a greater permanent force being applied
to the disk pack by the clamp. Preferably, the clamp and hub are constructed so
that surfaces
30 and
54 are parallel to one another, as shown in
FIG. 4, or a positive angle L is defined between the surfaces. The positive angle
L between surface
30 and surface
54 is preferably between 0°
(parallel) and 15°. A negative angle between the surfaces makes installation
of the retaining ring
14 more difficult, while an angle greater than 15°
may result in undesirable slippage of the retaining ring.
Because of the variable force which may be applied by the clamp to the disk
pack, the clamp is well suited for many disk drive applications. Whether a disk
drive includes one or multiple disks, the clamp of this invention eliminates not
only the need to use securing screws, but also eliminates the need to use O-rings
or other stabilizing features normally required to prevent radial displacement
of the disks with respect to the hub. Contamination is reduced as well because
screws are not used to set the clamp.
While the above description and drawings disclose and illustrate a preferred
embodiment, this invention is not limited to this specific embodiment. Those skilled
in the art to which the invention pertains may make other modifications employing
the principles of this invention, particularly upon considering the foregoing disclosure.
Therefore, by the appended claims, the applicant intends to cover any modifications
and any other embodiments which incorporate the features which constitute essential
features of the invention.
*
