U.S. patent application number 09/965316 was filed with the patent office on 2003-03-27 for shaft assembly providing a surface for forming joints.
Invention is credited to Bradley, Douglas James, Holcomb, Ronald Oral, Lum, Steven, Myers, Christopher Alan, Umin, Edward A..
Application Number | 20030060295 09/965316 |
Document ID | / |
Family ID | 25509797 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030060295 |
Kind Code |
A1 |
Myers, Christopher Alan ; et
al. |
March 27, 2003 |
Shaft assembly providing a surface for forming joints
Abstract
The present invention relates to an assembly that provides
metallic ends to a composite shaft and a method of fabricating such
an assembly. The composite shaft is preferably comprised of
reinforced fibers. A metallic inner sleeve is positioned in the
cavity of one end of the shaft. A metallic outer sleeve is
positioned around the end of the shaft having the inner sleeve
therein. The outer sleeve may include structural features, such as
dimples, that ensure a stable connection between the sleeve and the
shaft. The sleeves are compressibly forced onto the shaft, thereby
forming the assembly. Both sleeves are metallic, and therefore
provide a surface onto which weld joints can be formed. A preferred
method of assembly includes the steps of expanding the inner sleeve
and compressing the outer sleeve against the shaft.
Inventors: |
Myers, Christopher Alan;
(Holly, MI) ; Bradley, Douglas James; (Howell,
MI) ; Umin, Edward A.; (Rockwood, MI) ;
Holcomb, Ronald Oral; (Birmingham, MI) ; Lum,
Steven; (Honolulu, HI) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. Box 10395
Chicago
IL
60610
US
|
Family ID: |
25509797 |
Appl. No.: |
09/965316 |
Filed: |
September 27, 2001 |
Current U.S.
Class: |
464/181 |
Current CPC
Class: |
F16C 3/026 20130101;
Y10T 29/49909 20150115; Y10T 29/49293 20150115; Y10T 29/49913
20150115; Y10T 29/49911 20150115 |
Class at
Publication: |
464/181 |
International
Class: |
F16C 003/00 |
Claims
We claim:
1. A shaft assembly providing a surface for forming joints, said
assembly comprising: a composite shaft having an end portion and a
body portion, said end portion having an inner and outer surface
and defining an opening and a cavity; a metallic inner sleeve
having an exterior surface and being disposed within said cavity of
said end portion of said shaft, said exterior surface adjacent said
inner surface of said end portion of said shaft; a metallic outer
sleeve having an interior surface and being disposed around said
end portion of said shaft, said interior surface adjacent said
outer surface of said end portion of said shaft.
2. A shaft assembly according to claim 1, wherein said shaft
further comprises a taper portion between said end portion and said
body portion, said inner sleeve extending from at least said
opening to said taper portion.
3. A shaft assembly according to claim 1, wherein said shaft
includes fibers selected from the group consisting of boron, glass,
carbon, graphite, Kevlar, spectra, and spectran.
4. A shaft assembly according to claim 1, wherein said exterior
surface of said inner sleeve is in continuous contact with said
inner surface of said end portion of said shaft.
5. A shaft assembly according to claim 1, wherein said interior
surface of said outer sleeve is in continuous contact with said
outer surface of said end portion of said shaft.
6. A shaft assembly according to claim 1, wherein said interior
surface of said outer sleeve further comprises at least one raised
dimple, thereby forming an undulating pattern on said interior
surface.
7. A shaft assembly according to claim 6, wherein said end portion
of said shaft is complimentary to said undulating pattern of said
interior surface of said outer sleeve.
8. A shaft assembly according to claim 6, wherein said dimple
comprises a circular projection.
9. A shaft assembly according to claim 6, wherein said dimple
comprises an elongated projection.
10. A shaft assembly according to claim 1, wherein said inner
sleeve further comprises a first flange and said outer sleeve
further comprises a second flange.
11. A shaft assembly according to claim 10, further comprising a
joint formed between said first and second flanges.
12. A shaft assembly according to claim 11 wherein said joint is a
weld joint.
13. A driveshaft assembly providing a surface for forming joints,
said assembly, comprising: a composite tubular driveshaft having an
end portion and a body portion, said end portion having an inner
and outer surface and defining a cavity; a metallic inner sleeve
having an exterior surface and being disposed around said cavity of
said shaft, said exterior surface adjacent said inner surface of
said end portion of said shaft; a metallic outer sleeve having an
interior surface and being disposed about said end portion of said
shaft, said interior surface having dimples and being adjacent said
outer surface of said end portion of said shaft.
14. A driveshaft assembly according to claim 13, wherein said
driveshaft includes fibers selected from the group consisting of
boron, glass, carbon, graphite, Kevlar, spectra, and spectran.
15. A driveshaft assembly according to claim 13, wherein said inner
sleeve is partially disposed within said cavity.
16. A driveshaft assembly according to claim 5, wherein said inner
sleeve further comprises an angular portion and a flange.
17. A driveshaft assembly according to claim 13, wherein said outer
sleeve is partially disposed around said end portion of said
shaft.
18. A driveshaft assembly according to claim 17, wherein said outer
sleeve further comprises a conical portion and a flange, said
conical portion defining an angle adapted to prevent further
sliding of said outer sleeve around said end portion of said
shaft.
19. A driveshaft assembly according to claim 13, wherein said inner
sleeve further comprises a first flange and said outer sleeve
further comprises a second flange.
20. A driveshaft assembly according to claim 19 wherein said inner
sleeve further comprises a conical portion that defines an angle
adapted to prevent further insertion of said inner sleeve into said
cavity.
21. A driveshaft assembly according to claim 19, wherein said outer
sleeve further comprises a conical portion that defines an angle
adapted to prevent further sliding of said outer sleeve around said
end portion of said shaft.
22. A driveshaft assembly according to claim 19, further comprising
a joint formed between said first and second flanges.
23. A driveshaft assembly according to claim 22, wherein said joint
comprises a weld joint.
24. A method of fabricating a shaft assembly providing a surface
for forming joints, said method comprising: selecting a composite
shaft member having an end portion and a body portion, said end
portion having an inner and outer surface and defining a cavity;
selecting a metallic inner sleeve having an exterior surface;
selecting a metallic outer sleeve having an interior surface;
disposing said inner sleeve within said cavity of said end portion
of said shaft; disposing said outer sleeve around said end portion
of said shaft; expanding said inner sleeve such that said exterior
surface is adjacent said inner surface of said end portion of said
shaft; compressing said outer sleeve such that said interior
surface of said outer sleeve is adjacent said outer surface of said
end portion of said shaft.
25. The method according to claim 24, wherein said inner sleeve
further comprises a first flange and said outer sleeve further
comprises a second flange.
26. The method according to claim 25, further comprising forming a
joint between said first and second flanges.
27. The method according to claim 26, wherein said forming a joint
includes forming a weld joint.
28. The method according to claim 24, wherein said steps of
expanding said inner sleeve and compressing said outer sleeve are
performed simultaneously.
29. The method according to claim 24, wherein said expanding said
inner sleeve and compressing said outer sleeve are accomplished by
hydraulics.
30. The method according to claim 24, wherein said outer sleeve
further comprises at least one dimple positioned on said interior
surface of said outer sleeve.
31. The method according to claim 30, wherein said compressing said
outer sleeve continues until an undulating interface is formed
between said interior surface of said outer sleeve and said outer
surface of said shaft.
32. The method according to claim 24, wherein said inner sleeve
further comprises at least one dimple positioned on said exterior
surface of said inner sleeve.
33. The method according to claim 32, wherein said expanding said
inner sleeve continues until an undulating interface is formed
between said exterior surface of said inner sleeve and said inner
surface of said shaft.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an assembly of a composite
shaft and metallic sleeves. More specifically, the present
invention relates to an assembly that comprises inner and outer
metallic sleeves mechanically secured to a composite shaft. The
invention also provides a method for fabricating such an
assembly.
BACKGROUND OF THE INVENTION
[0002] Composite shafts are typically made in tubular form and are
comprised of fiber reinforced plastic material. The fibers can be
any number of fibrous materials, including glass and synthetic
polymers. The reinforcing fibers are wound around the tubular
composite, and are typically arranged such that they intersect each
other at various angles.
[0003] Composite shafts have been used in a variety of
applications, including vehicle drive shafts. U.S. Pat. No.
4,041,599 to Smith illustrates such an application of a composite
shaft and is herein incorporated by reference in its entirety.
[0004] Due to their composite nature and structure, composite
shafts offer several advantages over metal shafts. For example,
composite shafts are significantly lighter in weight than metal
shafts, thereby making them easy to transport and manipulate during
subsequent manufacturing. Also, their light weight reduces their
contribution to the overall weight of the article into which they
are incorporated, such as a motor vehicle. Furthermore, composite
shafts are more resistant to corrosion and other damaging processes
than metal shafts. Lastly, primarily due to the arrangement of the
fibers in the shaft, composite shafts have high strength and are
able to withstand high degrees of stress.
[0005] Due to the use of fibrous materials, it can prove difficult
to create a joint between a composite shaft and a metal member,
such as a hub. Direct weld joints between composite shafts and
metal do not normally create strong and durable connections on a
consistent and reliable basis. Many approaches to overcoming this
disadvantage have been proposed. For example, the use of metallic
sleeves to provide a metal surface onto which weld joints can be
formed has been proposed. Furthermore, many techniques for securing
such sleeves to composite shafts have been explored. U.S. Pat. No.
4,265,951 to Yates et al. discloses the integral formation of
metallic connector sleeves in the composite shaft. Another method
of securing the sleeves to the shaft employs an adhesive. For
example, U.S. Pat. No. 4,722,717 to Salzman et al. discloses a
series of grooves on the metallic insert and the composite shaft.
When aligned, the grooves form keyways into which adhesive material
can be injected. Once polymerized, the adhesive forms a bond
between the metallic insert and the composite shaft. Lastly,
temperature dependent methods of securing a metallic sleeve to a
composite shaft have been proposed. For example, a frozen metallic
sleeve can be inserted into a composite shaft and subsequently
warmed to expand the metal. In its expanded state, the sleeve is in
compression against the shaft.
[0006] These various approaches to securing metallic sleeves to
composite shafts, although effective, include several
disadvantages. For example, integral formation of sleeves onto a
shaft requires attachment of the sleeve at the time of
manufacturing the shaft. This requirement may inhibit the
manufacturing process and furthermore may inhibit other uses of the
composite shaft. The use of adhesives requires delicate
manufacturing techniques. Lastly, temperature dependent methods
require precise control over manufacturing conditions and the
manufacturing environment, adding time and expense to the
manufacturing process.
[0007] Due to the significant advantages offered by composite
shafts, demand for these shafts is currently increasing for a
variety of applications, including automobile driveshafts.
Therefore, there is a need for an assembly that provides a stable
surface onto which weld joints can be formed without adding any
additional disadvantages, such as burdensome complications to the
fabrication process. Furthermore, there is a need for a method of
producing such an assembly.
SUMMARY OF THE INVENTION
[0008] The present invention provides an assembly of a composite
shaft and metallic sleeves, thereby providing a surface onto which
a weld joint can be applied. The assembly of the present invention
comprises a composite tubular shaft and inner and outer metallic
sleeves. The inner and outer sleeves are adjacent the inner and
outer surfaces, respectively, of the composite shaft. The present
invention further provides a method for fabricating such an
assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a perspective view of a composite vehicle
driveshaft;
[0010] FIG. 2 is a fragmentary view of the shaft assembly partially
sectioned, in accordance with the present invention;
[0011] FIG. 3 is a cross sectional view of the assembly taken along
the line 3-3 in FIG. 2;
[0012] FIG. 4 is a partial cross-sectional view of a preferred
embodiment of the shaft assembly in accordance with the present
invention;
[0013] FIG. 5 is a partial cross-sectional view of an alternate
embodiment of the shaft assembly in accordance with the present
invention.
[0014] FIG. 6 is fragmentary view of a preferred embodiment of the
shaft assembly according to the present invention;
[0015] FIG. 7 is a cross sectional view of a preferred embodiment
of the shaft assembly taken along line 7-7 in FIG. 6; and
[0016] FIG. 8 is a flow diagram of a preferred method of making a
shaft assembly, in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] FIG. 1 illustrates a composite vehicle driveshaft 8 that can
be utilized in conjunction with the present invention.
[0018] FIG. 2 illustrates an assembly 10 in accordance with the
present invention. The assembly 10 comprises an inner sleeve 12, a
composite shaft 14 and an outer sleeve 16. The shaft 14 is
preferably a tubular member forming an inner cavity 18 and an
opening 20. The shaft 14 has an inner surface 22 that defines the
boundary of the inner cavity 18, and also has an outer surface 24
which is opposite the inner cavity 18.
[0019] In the preferred embodiment, a composite driveshaft 8 is
used as the shaft 14. The invention is not limited to this
application, however. Rather, the invention can be utilized in any
application where there is a need to create a load carrying
metallic interface with a composite shaft. Further examples of
suitable shafts include, but are not limited to, tie rods, steering
columns, and half shafts.
[0020] The composite shaft 14 includes an end portion 26 and a body
portion 28. Between the end portion 26 and body portion 28, the
shaft 14 may further include a tapered portion 30. The shaft 14 is
a structural composite tubular shaft known in the art and is
comprised of fiber filament reinforced material 32. The material 32
provides the structure of the shaft 14 and comprises, at least on
its outer surface, a series of wound fibers or filaments 34.
Preferably, several layers of fibers or filaments 34 are
successively wound around each other, with the fibers or filaments
34 of each layer situated at different angles to previous layers.
This arrangement of fibers or filaments 34 confers strength onto
the composite shaft 14.
[0021] Techniques for manufacturing the composite shaft 14 are
known in the art, and will not be described in detail herein.
Typically, layers of resin-coated filaments are wound successively
upon each other. A mandrel is used to support the developing shaft.
The fibers or filaments 34 may be boron, glass, carbon, graphite,
kevlar, spectra, spectran or any other natural or synthetic fiber
or filament, or any combination thereof. The fibers selected will
depend on the characteristics needed, such as strength and overall
shaft weight, for the application to which the assembly 10 will
ultimately be used. For driveshaft applications, carbon fibers are
preferred due to their light weight and relative strength.
Alternatively, any other suitable natural or synthetic fiber of
filament, or any combination thereof, may be used.
[0022] The shaft 14 preferably has a circular cross-sectional
shape. Alternatively, however, the shaft 14 can have any
cross-sectional shape appropriate for the application to which the
assembly 10 will be used. Examples of alternative cross-sectional
shapes include square, rectangular, triangular, and hexagonal
shapes. The only limitation on the cross-sectional shape of the
shaft 14 is that the shaft must be able to receive both the inner
12 and outer 16 sleeves in accordance with the present
invention.
[0023] The end portion 26 of shaft 14 provides the inner 22 and
outer 24 surfaces onto which the assembly 10 of the present
invention is formed. The inner cavity 18 and its opening 20 allow
the inner sleeve 12 to be slideably disposed therein.
[0024] Essentially, the cavity 18 can be any size. Preferably, as
will be developed more fully below, the cavity 18 is of a size that
allows minimal clearance of the inner sleeve 12 when the inner
sleeve 12 is disposed therein.
[0025] As best illustrated in FIG. 2, the shaft 14 preferably
includes a taper portion 30 between the end 26 and body portions
28. The taper portion 30 preferably defines structural features
that assist positioning of the inner sleeve 12 in the cavity 18 of
the end portion 26. For example, the taper portion 30 may define a
slant on the inner surface 22 of the shaft 14. One end of the inner
sleeve 12 may define a complimentary slant such that, when the
inner sleeve 12 is placed into the cavity 18, a stopping point is
reached when the complimentary slants come into contact.
Alternatively, the shaft 14 may not include a taper portion 30.
[0026] The inner sleeve 12 is preferably a metal member that fits
within the inner cavity 18 of the shaft 14. Any metal suitable for
providing a weld surface can be utilized for the inner sleeve 12.
Due to its light weight, ready availability, and ability to form
strong weld joints on its surface, aluminum is preferred.
Alternatively, steel or any other suitable metal, alloy, or other
material can be used for the inner sleeve.
[0027] Similar to the shaft 14, the inner sleeve 12 is preferably a
tubular member having interior 36 and exterior 38 surfaces and
defining a cavity 40. The cavity 40 of the inner sleeve 12 can
essentially be any size and shape. The size and shape of the cavity
40 defined by the inner sleeve 12 will depend on the application
for which the assembly 10 is used. Alternatively, the inner sleeve
12 may be a solid member, not defining a cavity at all. In this
embodiment, the inner sleeve 12 effectively defines a solid plug
that fits within the cavity 18 of the shaft 14. This embodiment
allows additional surface area for supporting a weld joint 13,
among other benefits. In additional alternate embodiments, the
inner sleeve 12 can have any form that allows the inner 12 and
outer 16 sleeves to be positioned within and around, respectively,
the shaft 14 in accordance with the present invention, as will be
developed more fully below.
[0028] The inner sleeve 12 preferably has a circular
cross-sectional shape. Alternatively, however, the inner sleeve 12
can have any cross-sectional shape appropriate to the application
to which the assembly 10 will be used. Examples of alternative
cross-sectional shapes include square, rectangular, triangular, and
hexagonal shapes. It is preferred that the exterior surface 38 of
the inner sleeve 12 have a shape complimentary to the inner surface
22 of the shaft 14. This does not, however, dictate that the cavity
40 defined by the inner sleeve 12 have a similar shape. Indeed the
exterior surface 38 and cavity 40 of the inner sleeve 12 can have
two completely different shapes. For example, the exterior surface
38 can be circular in nature, complimentary to a tubular shaft 14,
while the cavity 40 of the inner sleeve 12 defines a square,
rectangular, triangular or hexagonal shape.
[0029] The inner sleeve 12 may slide within the cavity 18 of the
shaft 14 in its entirety. In a preferred embodiment, however, the
inner sleeve 12 defines three distinct regions. As shown in FIG. 4,
a first region 42 slideably fits into the cavity 18 of the shaft 14
in accordance with the description of the inner sleeve 12 above. A
conical region 44 defines an angle 46 in the inner sleeve 12. The
angle preferably extends the inner sleeve 12 outward from the
cavity 18 of the shaft 14. However, any type of bend, kink, or
other disruption in the inner sleeve 12 may be used as the angle
46. It will be appreciated that, as shown in FIG. 4, the angle 46
preferably defines a structural feature in the inner sleeve 12 that
inhibits further insertion of the inner sleeve 12 into the cavity
18 of the shaft 14 once the angle 46 comes into contact with
opening 20 of the shaft 14. An outer region 48 of the inner sleeve
12 of this embodiment defines a flange 50. The flange provides
surface area onto which a weld joint or other joint can be located.
For example, as shown in FIGS. 4 and 5, the flange 50 can support a
weld joint to a portion of the outer sleeve 16 or a separately
attached member. Also, the flange 50 may define elements, such as
through openings, threaded openings, projections, clips, hooks, or
other structural features that facilitate correction of the inner
sleeve 12 to the outer sleeve 16 and/or other members. As shown in
FIG. 4, it is preferable that the angle 46 is of a configuration
such that the top surface of the flange 50 is located at
approximately the midpoint of the thickness of the shaft 14.
[0030] In an alternate embodiment, as shown in FIG. 5, the inner
sleeve 12 may not include an angle 46, effectively defining a
continuous surface. This embodiment facilitates the process of
fabricating the assembly 10 of the present invention.
[0031] No matter the form of the inner sleeve 12, the outer
diameter 52 must allow at least the first region 42 to fit within
the cavity 18 of the shaft. The clearance 54 between the exterior
surface 38 of the inner sleeve 12 and the cavity 18 of the shaft 13
is preferably large enough to allow the inner sleeve 12 to slide
within the cavity 18, but small enough to minimize the force needed
to place the inner sleeve 12 in adjacent the inner surface 22 of
the shaft 14 during fabrication of the assembly 10. Considering
these preferences, a clearance 54 of between approximately 0.1 and
1.0 mm is preferred, and a clearance of approximately 0.4 mm is
particularly preferred.
[0032] Similar to the inner sleeve 12, the outer sleeve 16 is
preferably a metal member. Thus, any metal suitable for providing a
weld surface can be used as the outer sleeve 16. Again, due to its
relatively light weight and ability to form strong weld joints,
aluminum is preferred. Alternatively, steel or any other metal,
alloy, or other material can be used.
[0033] The outer sleeve 16 is preferably a tubular member having
interior 56 and exterior 58 surfaces and defining a cavity 60. The
outer sleeve 16 fits over the end portion 26 of the composite shaft
14. Thus, the cavity 60 of the outer sleeve 16 can be essentially
any size and shape so long as it is capable of receiving the end
portion 26 of the shaft 14. The size and shape of the cavity 60 of
the outer sleeve 16 will therefore depend on the configuration of
the end portion 26 of the shaft 14.
[0034] The outer sleeve 16 preferably has a circular
cross-sectional shape. Alternatively, however, the outer sleeve 16
can have any cross-sectional shape appropriate to the application
to which the assembly 10 will be used. For example, the outer
sleeve 16 can have a square, rectangular, triangular, or hexagonal
cross-sectional shape. It is preferred that the cavity 60 of the
outer sleeve 16 have a shape complimentary to the outer surface 24
of the shaft 14. This does not dictate that the exterior surface 58
of the outer sleeve 16 have a similar shape. The exterior surface
58 and cavity 60 can have two completely different shapes. For
example, the cavity 60 can define a circular cross-section,
complimentary to a tubular shaft 14, while the exterior surface 58
defines a square, rectangular, or triangular shape.
[0035] The outer sleeve 16 may slide over the outer surface 24 of
the end portion 26 of the shaft 14 in its entirety. In a preferred
embodiment, however, the outer sleeve 16 defines three distinct
regions. This embodiment is illustrated in FIG. 3. A first region
62 slideably fits over the outer surface 24 of the end portion 26
of the shaft 14 in accordance with the description of the outer
sleeve 16 above. A conical region 64 defines an angle 66 in the
outer sleeve 16. The angle 66 preferably extends the outer sleeve
16 toward the cavity 18 of the shaft. However, any type of bend,
kink, or other disruption in the outer sleeve 16 may be used as the
angle 66. It will be appreciated that the angle 66 may define a
structural feature in the outer sleeve 16 that inhibits further
movement of the outer sleeve along the shaft 14 once the angle 66
comes into contact with the opening 20 of the shaft.
[0036] An outer region 68 of the outer sleeve 16 of this embodiment
defines a flange 70. The flange 70 provides surface area onto which
a weld joint or the joint can be located. For example, as shown in
FIGS. 3 and 4, the flange 70 can support a weld joint to the flange
50 of the inner sleeve or a separately attached member. Also, the
flange 70 may define elements, such as through openings, threaded
openings, projections, clips, hooks, or other structural features
that facilitate connection of the outer sleeve 16 to the inner
sleeve 12 and/or other members. As illustrated in FIG. 3, it is
preferable that the angle 66 of the outer sleeve 16 be such that
the outer sleeve is essentially a mirror image of the inner sleeve
12. This allows the top of the inner sleeve flange 50 and bottom of
the outer sleeve flange 70 to meet at approximately the midpoint of
the thickness of the shaft 14. In an alternate embodiment, shown in
FIG. 4, the angle 66 is such that the interface between the two
flanges 50, 70 is located at a position that corresponds to
approximately the inner surface 22 of the shaft 14. In this
embodiment, the inner sleeve 12 has a continuous surface, i.e.,
there is no angle 46. Of course, any combination of the two angles
46, 66 can be utilized to place the flanges 50, 70 at a desired
location relative to the shaft 14.
[0037] No matter the form of the outer sleeve 16, the inner
diameter 72 must allow at least the first region 62 to fit over the
end portion 26 of the shaft 14. The clearance between the interior
surface 56 of the outer sleeve 16 and the shaft 14 is preferably
large enough to allow the outer sleeve 16 to slide over the end
portion 26 of the shaft 14, but small enough to minimize the force
needed to place the outer sleeve 16 adjacent the outer surface 24
of the shaft 14 during fabrication of the assembly 10. Considering
these preferences, a clearance 74 of between approximately 0.1 and
1.0 mm is preferred, and a clearance 74 of approximately 0.4 mm is
particularly preferred.
[0038] Preferably, the two flanges 50, 70 are secured to each
other, forming an edge 76. It is preferred to use a weld joint to
secure the flanges 50, 70 to each other. Alternatively, any type of
fastening or securement means can be used, such as rivets, threaded
fasteners with bolts, and adhesives.
[0039] As best illustrated in FIGS. 3 and 4, when the inner 12 and
outer 16 sleeves are in position within and about, respectively,
the composite shaft 14, one surface of each sleeve 12, 16 is
preferably in contact with one surface of the shaft 14. Preferably,
each area of contact between the sleeve 12, 16 and the shaft 14
constitutes a continuous interface line. That is, it is preferred
that contact exist over the entire area of interface between the
sleeves 12, 16 and the shaft 14. Alternatively, contact may be
intermittent in nature. Also preferably, the contact between the
exterior surface 38 of the inner sleeve 12 and the inner surface 22
of the shaft 14, and the interior surface 56 of the outer sleeve 16
and the outer surface 24 of the shaft 14 constitutes a flat
interface.
[0040] FIGS. 5 and 6 illustrate an alternate embodiment of the
assembly 10 according to the present invention. In this embodiment,
dimples 78 are present on the outer sleeve 16. The dimples 78 serve
to provide a mechanism to lock the outer sleeve 16 to the shaft 14
in the assembly 10. This locking is achieved by complimentary
undulating patterns in the area of contact between the outer sleeve
16 and the shaft 14. The undulating pattern on the interior surface
56 of the outer sleeve 16 is preferably formed by the dimples 78.
The undulating pattern on the shaft 14 is preferably formed during
fabrication of the assembly 10 due to the presence of the dimples
78, which will be developed more fully below. Alternatively, the
shaft 14 can form recesses complimentary in size and shape to the
dimples 78, thereby defining an undulating pattern. Preferably, the
dimples 78 are integrally formed by the interior surface of the
outer sleeve 16. Alternatively, the dimples 78 can comprise
separately attached members, preferably metal. In general, the
dimples 78 are small, raised bumps having a slight curvature.
Preferably, the dimples 78 are circular in shape and are positioned
about the entire interior surface 56 of the outer sleeve 16 at
regular intervals. Particularly preferred is an arrangement of
dimples 78 positioned equidistant from each other. Alternatively,
the dimples 78 can have an elongated shape or any other shape so
long as the raised nature of the dimples 78 as compared to the area
of the surface not having dimples 78 is retained. Furthermore, the
dimples 78 can be positioned on the interior surface 56 in any
given pattern, including random placement and higher or exclusive
placement at areas of greater stress. Ultimately, the size, shape,
position, and orientation of the dimples 78 will depend on the
specific load requirements of the assembly 10. The exterior surface
58 of the inner sleeve 12 can also include dimples 78 in the same
manner described above for the outer sleeve 16.
[0041] A preferred method of fabricating the assembly 10 of the
present invention will now be described. The assembly 10 of the
present invention can be fabricated from its component parts by
utilizing a sizing tool capable of expanding the inner sleeve 12
and compressing the outer sleeve 16. In a first step 80 of the
preferred method of fabricating the assembly 10, appropriate
components are selected. In the selection step, the shaft 14, inner
sleeve 12, and outer sleeve 16 are selected in accordance with the
requirements of the present invention. Thus, a shaft 14 is selected
as appropriate for the function to which the assembly 10 will be
applied. The inner sleeve 12 and outer sleeve 16 are selected based
upon the material appropriate for the ultimate use of the assembly
10. Also, the sleeves 12, 16 are selected based upon size
appropriate for use with the selected shaft 14 in accordance with
the assembly 10 of the present invention. The outer diameter 52 of
the inner sleeve 12 must allow the inner sleeve 12 to slideably fit
within the inner cavity 18 of the end portion 26 of the shaft 14.
Also, the outer diameter 52 of the inner sleeve 12 must be large
enough to allow the inner sleeve 12 to be positioned adjacent the
inner surface 22 of the end portion 26. Similarly, the inner
diameter 72 of the outer sleeve 16 must allow the outer sleeve 16
to slide over the end portion 26 of the shaft 14. Also, the inner
diameter 72 of the outer sleeve 16 must be small enough to allow
the outer sleeve 16 to be positioned adjacent the outer surface 24
of the shaft 14.
[0042] Prior to placing the sleeves 12, 16 in position, the sleeves
can be secured 82 to each other by forming a weld joint or other
securement means at the interface between the flanges 50, 70 if
desired. Alternatively, this securement can be performed at any
subsequent point in the fabrication process or may be omitted.
[0043] In a next step 84, the inner 12 and outer 16 sleeves are
positioned at the desired locations of the shaft end portion 26.
This is accomplished by placing at least the first region 42 of the
inner sleeve 12 inside the inner cavity 18 of the shaft 14, and
placing at least the first region 62 of the outer sleeve 16 over
the end portion 26 of the shaft 14. If one or both angles 46, 66
are present, proper positioning of the sleeve(s) 12, 16 can be
accomplished by moving the sleeve(s) along the shaft 12 until the
angle(s) 46, 66 are in contact with the opening 20. If the shaft 14
includes a tapered portion 30, proper positioning of the inner
sleeve 12 can be accomplished by moving the inner sleeve 12 along
the shaft 12 until interaction with the taper portion 30 of the
shaft 14 is achieved.
[0044] Once the inner 12 and outer 16 sleeves are in their desired
positions, a sizing tool of appropriate size is placed 84 about the
assembly 10. If the sizing tool is only capable of performing a
single sizing operation at one time, it is preferred that the tool
expand the inner sleeve 12 first, and then compress the outer
sleeve, as depicted in steps 88 and 90 of FIG. 8. Alternatively,
any order can be used. If the tool is capable of simultaneously
expanding the inner sleeve 12 and compressing the outer sleeve 16,
the appropriate portions of the tool are placed within the inner
sleeve 12 and around the outer sleeve 16. In this position, the
sizing tool is able to simultaneously expand and compress (step 92)
the inner 12 and outer 16 sleeves, respectively, thereby achieving
the preferred adjacency between the exterior surface 56 of the
inner sleeve 12 and the inner surface 22 of the shaft 14 and the
interior surface 38 of the outer sleeve 16 and the outer surface 24
of the shaft 14. Preferably, a hydraulic sizing tool of appropriate
size is utilized for this step of the fabrication process. Also
preferable, the sizing tool is capable of simultaneously expanding
the inner sleeve 12 and compressing the outer sleeve 16. A tube
sizing machine, such as the I/O 3000 from Eagle Eaton Leonard,
capable of performing both inner diameter and outer diameter
manipulations, is preferred.
[0045] Once in position, the sizing tool is activated to expand 86
the inner sleeve 12 and compress 88 the outer sleeve 16. The
expansion and compression preferably occur simultaneously 92. Thus,
in a preferred method, the sizing tool is activated to
simultaneously expand the inner sleeve 12 until contact is made
with the composite shaft 14 and compress the outer sleeve 16
against the shaft 14. Both actions force the respective sleeve onto
the shaft 14, thereby forming the assembly 10 of the present
invention. Alternatively, the expansion and compression can occur
independently of each other, and in either order. If dimples 78 are
present on either sleeve 12, 16, the expansion and compression
preferably proceed until an undulating pattern is formed at the
interface of the respective sleeves 12, 16 and shaft 14, thereby
achieving a mechanical lock between the sleeves 12, 16 and the
shaft 14.
[0046] Lastly, the finished assembly 10 is removed 94 from the
sizing tool. The preferred method of fabricating the assembly 10 is
now complete.
[0047] The foregoing disclosure is the best mode devised by the
inventors for practicing the invention. It is apparent, however,
that several variations in assemblies of composite shafts and
metallic ends and methods of fabricating such assemblies in
accordance with the present invention may be obvious to one skilled
in the art. Inasmuch as the foregoing disclosure is intended to
enable one skilled in the pertinent art to practice the instant
invention, it should be not construed to be limited thereby, but
should be construed to include such aforementioned obvious
variations. As such, the present invention should be limited only
by spirit and scope of the following claims.
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