U.S. patent application number 14/158280 was filed with the patent office on 2015-04-30 for propshaft assembly with damper.
This patent application is currently assigned to AMERICAN AXLE & MANUFACTURING, INC.. The applicant listed for this patent is AMERICAN AXLE & MANUFACTURING, INC.. Invention is credited to Jason Ley, Jeffrey P. Nyquist, Zhaohui Sun, Michael Voight.
Application Number | 20150119153 14/158280 |
Document ID | / |
Family ID | 52811883 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150119153 |
Kind Code |
A1 |
Ley; Jason ; et al. |
April 30, 2015 |
Propshaft Assembly With Damper
Abstract
A propshaft assembly that includes a tubular member, first and
second end connections coupled to opposite ends of the tubular
member and a damper that is received in the tubular member and
positioned between the first and second end connections. The
tubular member has a wall member that defines an interior
circumferential surface. The damper has a first damping device, a
second damping device and a third damping device. The first damping
device has a first core and a first damping member that is fixed to
the first core. The first damping member extends helically about
the first core and engages the interior circumferential surface.
The second damping device is formed of foam and is positioned in
the tubular member between the first and third damping devices. The
second damping device engages the interior circumferential surface.
The third damping device has a second core and a second damping
member that is fixed to the second core. The second damping member
extends helically about the second core and engages the interior
circumferential surface.
Inventors: |
Ley; Jason; (Detroit,
MI) ; Sun; Zhaohui; (Detroit, MI) ; Nyquist;
Jeffrey P.; (Detroit, MI) ; Voight; Michael;
(Detroit, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AMERICAN AXLE & MANUFACTURING, INC. |
Detroit |
MI |
US |
|
|
Assignee: |
AMERICAN AXLE & MANUFACTURING,
INC.
Detroit
MI
|
Family ID: |
52811883 |
Appl. No.: |
14/158280 |
Filed: |
January 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61897721 |
Oct 30, 2013 |
|
|
|
Current U.S.
Class: |
464/180 ;
29/428 |
Current CPC
Class: |
F16C 3/023 20130101;
Y10T 29/49826 20150115; Y10T 464/50 20150115; B21D 39/04 20130101;
F16F 15/12 20130101; B21D 53/88 20130101; B60K 17/22 20130101; F16C
3/02 20130101; F16F 7/06 20130101 |
Class at
Publication: |
464/180 ;
29/428 |
International
Class: |
F16C 3/02 20060101
F16C003/02 |
Claims
1. A propshaft assembly comprising: a tubular member having a wall
member that defines an interior circumferential surface; first and
second end connections coupled to opposite ends of the tubular
member; and a damper received in the tubular member and positioned
between the first and second end connections, the damper comprising
a first damping device, a second damping device and a third damping
device, the first damping device comprising a first core and a
first damping member that is fixed to the first core, the first
damping member extending helically about the first core and
engaging the interior circumferential surface, the second damping
device being formed of foam and being positioned in the tubular
member between the first and third damping devices, the second
damping device engaging the interior circumferential surface, the
third damping device comprising a second core and a second damping
member that is fixed to the second core, the second damping member
extending helically about the second core and engaging the interior
circumferential surface.
2. The propshaft assembly of claim 1, wherein the first damping
device is spaced apart from the second damping device along a
longitudinal axis of the tubular member.
3. The propshaft assembly of claim 2, wherein the third damping
device is spaced apart from the second damping device along the
longitudinal axis of the tubular member.
4. The propshaft assembly of claim 1, wherein the first, second and
third damping devices are fixed together in an axial direction so
as to be capable of being inserted to the tubular member as a
unit.
5. The propshaft assembly of claim 4, wherein the first and second
cores are portions of a unitarily formed core member and wherein
the second damping device is mounted on the core member.
6. The propshaft assembly of claim 4, wherein the second damping
device comprises a strip of foam that is wound onto the core
member.
7. The propshaft assembly of claim 1, wherein the foam is a
closed-cell foam and wherein the closed-cell foam has a density of
between 1.0 pounds per cubic foot and 2.5 pounds per cubic
foot.
8. The propshaft assembly of claim 7, wherein the density is
between 1.2 pounds per cubic foot and 1.8 pounds per cubic
foot.
9. The propshaft assembly of claim 7, wherein the density is
between 1.20 pounds per cubic foot and 1.60 pounds per cubic
foot.
10. The propshaft assembly of claim 1, wherein the core is formed
of a fibrous material.
11. The propshaft assembly of claim 10, wherein the fibrous
material is a cardboard or a paperboard.
12. The propshaft assembly of claim 1, wherein a diameter of the
second damping device taken about an outside surface of the second
damping device is 5% to 20% larger than a diameter of the inside
circumferential surface prior to installation of the damper into
the tubular member.
13. The propshaft assembly of claim 12, wherein the diameter of the
second damping device taken about the outside surface of the second
damping device is about 10% larger than the diameter of the inside
circumferential surface prior to installation of the damper into
the tubular member.
14. A propshaft assembly comprising: a tubular member having a wall
member that defines an interior circumferential surface; first and
second end connections coupled to opposite ends of the tubular
member; and a damper received in the tubular member and positioned
between the first and second end connections and engaging the
interior circumferential surface, the damper being formed out of a
foam material, the damper defining a plurality of longitudinally
extending grooves that are formed in the foam material, the
longitudinally extending grooves being spaced evenly apart around
the circumference of the damper.
15-19. (canceled)
20. A method for assembling a propshaft assembly, the method
comprising: providing a tubular member having an annular wall
member that defines an interior circumferential surface; providing
a damper having a first damping member, a second damping member and
a third damping member, each of the first, second and third damping
members being a discrete structure, the second damping member being
formed of foam; inserting the first, second and third damping
members into the tubular member, each of the first, second and
third damping members directly engaging the interior
circumferential surface and attenuating shell mode vibration
transmitted through the tubular member, wherein the second damping
member is disposed between the first and third damping members
wherein the second damping member is inserted through one of the
first and third damping members.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/897,721 filed Oct. 30, 2013, the
disclosure of which is incorporated by reference as if fully set
forth in detail herein.
FIELD
[0002] The present disclosure relates to a propshaft assembly with
a damper.
BACKGROUND
[0003] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0004] The consumers of modern automotive vehicles are increasingly
influenced in their purchasing decisions and in their opinions of
the quality of a vehicle by their satisfaction with the vehicle's
sound quality. In this regard, consumers increasingly expect the
interior of the vehicle to be quiet and free of noise from the
power train and drive line. Consequently, vehicle manufacturers and
their suppliers are under constant pressure to reduce noise to meet
the increasingly stringent expectations of consumers.
[0005] Drive line components and their integration into a vehicle
typically play a significant role in sound quality of a vehicle as
they can provide the forcing function that excites specific
driveline, suspension and body resonances to produce noise. Since
this noise can be tonal in nature, it is usually readily detected
by the occupants of a vehicle regardless of other noise levels.
Common driveline excitation sources can include driveline imbalance
and/or run-out, fluctuations in engine torque, engine idle shake,
and motion variation in the meshing gear teeth of the hypoid gear
set (i.e., the pinion gear and the ring gear of a differential
assembly).
[0006] Propshafts are typically employed to transmit rotary power
in a drive line. Modern automotive propshafts are commonly formed
of relatively thin-walled steel or aluminum tubing and as such, can
be receptive to various driveline excitation sources. The various
excitation sources can typically cause the propshaft to vibrate in
a bending (lateral) mode, a torsion mode and a shell mode. Bending
mode vibration is a phenomenon wherein energy is transmitted
longitudinally along the shaft and causes the shaft to bend at one
or more locations. Torsion mode vibration is a phenomenon wherein
energy is transmitted tangentially through the shaft and causes the
shaft to twist. Shell mode vibration is a phenomenon wherein a
standing wave is transmitted circumferentially about the shaft and
causes the cross-section of the shaft to deflect or bend along one
or more axes.
[0007] Several techniques have been employed to attenuate
vibrations in propshafts including the use of weights and liners.
U.S. Pat. No. 2,001,166 to Swennes, for example, discloses the use
of a pair of discrete plugs or weights to attenuate vibrations. The
weights of the '166 patent are frictionally engaged to the
propshaft at experimentally-derived locations and as such, it
appears that the weights are employed as a resistive means to
attenuate bending mode vibration. As used herein, resistive
attenuation of vibration refers to a vibration attenuation means
that deforms as vibration energy is transmitted through it (i.e.,
the vibration attenuation means) so that the vibration attenuation
means absorbs (and thereby attenuates) the vibration energy. While
this technique can be effective, the additional mass of the weights
can require changes in the propshaft mounting hardware and/or
propshaft geometry (e.g., wall thickness) and/or can change the
critical speed of the propshaft. Moreover, as the plugs tend to be
relatively short, they typically would not effectively attenuate
shell mode vibration or torsion mode vibration.
[0008] U.S. Pat. No. 2,751,765 to Rowland et al., U.S. Pat. No.
4,014,184 to Stark and U.S. Pat. Nos. 4,909,361 and 5,976,021 to
Stark et al. disclose hollow liners for a propshaft. The '765 and
'184 patents appear to disclose hollow multi-ply paperboard or
cardboard liners that are press-fit to the propshaft; the liners
are relatively long and appear to extend substantially
coextensively with the hollow shaft. The '361 and '021 patents
appear to disclose liners having a hollow cardboard core and a
helical retaining strip that extends a relatively short distance
(e.g., 0.03 inch) from the outside diameter of the core. The
retaining strip has high frictional properties to frictionally
engage the propshaft. Accordingly, the liners of the '765, '184,
'361 and '021 patents appear to disclose a resistive means for
attenuating shell mode vibration.
[0009] In view of the foregoing, there remains a need in the art
for an improved propshaft assembly that is more effectively damped
to control shell mode vibration.
SUMMARY
[0010] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0011] In one form, the present teachings provide a propshaft
assembly that includes a tubular member, first and second end
connections coupled to opposite ends of the tubular member and a
damper that is received in the tubular member and positioned
between the first and second end connections. The tubular member
has a wall member that defines an interior circumferential surface.
The damper has a first damping device, a second damping device and
a third damping device. The first damping device has a first core
and a first damping member that is fixed to the first core. The
first damping member extends helically about the first core and
engages the interior circumferential surface. The second damping
device is formed of foam and is positioned in the tubular member
between the first and third damping devices. The second damping
device engages the interior circumferential surface. The third
damping device has a second core and a second damping member that
is fixed to the second core. The second damping member extends
helically about the second core and engages the interior
circumferential surface.
[0012] In another form, the present teachings provide a propshaft
assembly that includes a tubular member, first and second end
connections coupled to opposite ends of the tubular member and a
damper that is received in the tubular member. The tubular member
has a wall member that defines an interior circumferential surface.
The damper is positioned between the first and second end
connections and engages the interior circumferential surface. The
damper is formed out of a foam material and defines a plurality of
longitudinally extending grooves. The longitudinally extending
grooves are spaced evenly apart around the circumference of the
damper.
[0013] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0014] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0015] FIG. 1 is a schematic illustration of an exemplary vehicle
constructed in accordance with the teachings of the present
disclosure;
[0016] FIG. 2 is a top partially cut-away view of a portion of the
vehicle of FIG. 1 illustrating the rear axle and the propshaft
assembly in greater detail;
[0017] FIG. 3 is a sectional view of a portion of the rear axle and
the propshaft assembly;
[0018] FIG. 4 is a top, partially cut away view of the propshaft
assembly;
[0019] FIG. 5 is a view similar to that of FIG. 4 but illustrating
a propshaft assembly that employs a tubular member having two
necked-down areas;
[0020] FIG. 6 is a lateral section view of a portion of the of the
propshaft assembly of FIG. 4, taken through a first damping device
of a damper;
[0021] FIG. 7 is a perspective view of an alternately constructed
second damping device;
[0022] FIG. 8 is a perspective view of a second damping device
installed over a ram of an assembly tool that is employed to insert
the second damping device into a tubular member;
[0023] FIG. 9 is a perspective view of another damper constructed
in accordance with the teachings of the present disclosure.
[0024] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0025] With reference to FIG. 1 of the drawings, an exemplary
vehicle constructed in accordance with the teachings of the present
disclosure is generally indicated by reference numeral 10. The
vehicle 10 can include an engine 14 and a drive line 16. The drive
line 16 can include a transmission 18, a propshaft assembly 20, a
rear axle 22 and a plurality of wheels 24. The engine 14 can
produce rotary power that can be transmitted to the transmission 18
in a conventional and well known manner. The transmission 18 can be
conventionally configured and can include a transmission output
shaft 18a and a gear reduction unit (not specifically shown). As is
well known in the art, the gear reduction unit can change the speed
and torque of the rotary power provided by the engine such that a
rotary output of the transmission 18 (which can be transmitted
through the transmission output shaft 18a) can have a relatively
lower speed and higher torque than that which was input to the
transmission 18. The propshaft assembly 20 can be coupled for
rotation with the transmission output member 18a to permit drive
torque to be transmitted from the transmission 18 to the rear axle
22 where can be selectively apportioned in a predetermined manner
to the left and right rear wheels 24a and 24b, respectively.
[0026] It will be appreciated that while the vehicle in the
particular example provided employs a drive line with a rear-wheel
drive arrangement, the teachings of the present disclosure have
broader applicability. In this regard, a shaft assembly constructed
in accordance with the teachings of the present disclosure may
interconnect a first drive line component with a second drive line
component to transmit torque therebetween. In the context of an
automotive vehicle, the drive line components could be a
transmission, a transfer case, a viscous coupling, an axle
assembly, or a differential, for example.
[0027] With reference to FIG. 2, the rear axle 22 can include a
differential assembly 30, a left axle shaft assembly 32 and a right
axle shaft assembly 34. The differential assembly 30 can include a
housing 40, a differential unit 42 and an input shaft assembly 44.
The housing 40 can support the differential unit 42 for rotation
about a first axis 46 and can further support the input shaft
assembly 44 for rotation about a second axis 48 that is
perpendicular to the first axis 46.
[0028] With additional reference to FIG. 3, the housing 40 can be
formed in a suitable casting process and thereafter machined as
required. The housing 40 can includes a wall member 50 that can
define a central cavity 52 that can have a left axle aperture 54, a
right axle aperture 56, and an input shaft aperture 58. The
differential unit 42 can be disposed within the central cavity 52
of the housing 40 and can include a case 70, a ring gear 72, which
can be fixed for rotation with the case 70, and a gearset 74 that
can be disposed within the case 70. The gearset 74 can include
first and second side gears 82 and 86 and a plurality of
differential pinions 88, which can be rotatably supported on pinion
shafts 90 that can be mounted to the case 70. The case 70 can
include a pair of trunnions 92 and 96 and a gear cavity 98. A pair
of bearing assemblies 102 and 106 can support the trunnions 92 and
96, respectively, for rotation about the first axis 46. The left
and right axle assemblies 32 and 34 can extend through the left and
right axle apertures 54 and 56, respectively, where they can be
coupled for rotation about the first axis 46 with the first and
second side gears 82 and 86, respectively. The case 70 can be
operable for supporting the plurality of differential pinions 88
for rotation within the gear cavity 98 about one or more axes that
can be perpendicular to the first axis 46. The first and second
side gears 82 and 86 each include a plurality of teeth 108 which
meshingly engage teeth 110 that are formed on the differential
pinions 88.
[0029] The input shaft assembly 44 can extend through the input
shaft aperture 58 where it can be supported in the housing 40 for
rotation about the second axis 48. The input shaft assembly 44 can
include an input shaft 120, a pinion gear 122 having a plurality of
pinion teeth 124 that meshingly engage the teeth 126 that are
formed on the ring gear 72, and a pair of bearing assemblies 128
and 130 that can cooperate with the housing 40 to rotatably support
the input shaft 120. The input shaft assembly 44 can be coupled for
rotation with the propshaft assembly 20 and can be operable for
transmitting drive torque to the differential unit 42. More
specifically, drive torque received the input shaft 120 can be
transmitted by the pinion teeth 124 to the teeth 126 of the ring
gear 72 such that drive torque is distributed through the
differential pinions 88 to the first and second side gears 82 and
86.
[0030] The left and right axle shaft assemblies 32 and 34 can
include an axle tube 150 that can be fixed to the associated axle
aperture 54 and 56, respectively, and an axle half-shaft 152 that
can be supported for rotation in the axle tube 150 about the first
axis 46. Each of the axle half-shafts 152 can include an externally
splined portion 154 that can meshingly engage a mating internally
splined portion (not specifically shown) that can be formed into
the first and second side gears 82 and 86, respectively.
[0031] With reference to FIG. 4, the propshaft assembly 20 can
include a tubular member 200, a first end connection 202a, a second
end connection 202b, and a damper 204. The tubular member and the
first and second end connections 202a and 202b can be conventional
in their construction and need not be described in significant
detail herein. Briefly, the tubular member 200 can be formed of an
appropriate structural material, such as steel or aluminum, and can
include an annular wall member 224. The annular wall member 224 can
have an interior circumferential surface 228 and can define a
hollow cavity 230. Depending on the particular requirements of the
vehicle 10 (FIG. 1), the wall member 224 may be sized in a uniform
manner over its entire length, as is shown in FIG. 4, or may be
necked down or stepped in diameter in one or more areas along its
length, as is shown in FIG. 5. The first and second end connections
202a and 202b can be configured to couple the propshaft assembly 20
to other rotary components of the vehicle 10 (FIG. 1) in a desired
manner to transmit rotary power therebetween. For example, the
first end connection 202a and/or the second end connection 202b
could comprise a universal joint (e.g., Cardan or constant velocity
joint) or components thereof. Optionally, one or both of the first
and second end connections 202a and 202b can be vented to permit
air to flow into or out of the hollow cavity 230. In the particular
example provided, a vent 232 is installed to each of the first and
second end connections 202a and 202b. In the particular example
provided, the vents 232 comprise holes formed in the first and
second end connections 202a and 202b, but it will be appreciated
that the vent(s) 232 can be constructed in any desired manner.
[0032] The damper 204 can comprise a first damping device 250, a
second damping device 252 and a third damping device 254. The
damper 204 can be effective in attenuating shell mode vibration
transmitted through the tubular member 200, but may also be
effective in attenuating other vibration modes, such as torsion
mode vibration and/or bending mode vibration through the tubular
member 200. Shell mode vibration, also known as breathing mode
vibration, is a phenomenon wherein a standing wave is transmitted
circumferentially about the tubular member 200 and causes the
cross-section of the shaft to deflect (e.g., expand or contract)
and/or bend along one or more axes. Torsion mode vibration is a
phenomenon wherein energy is transmitted tangentially through the
shaft and causes the shaft to twist. Bending mode vibration is a
phenomenon wherein energy is transmitted longitudinally along the
shaft and causes the shaft to bend at one or more locations.
[0033] The first damping device 250 can be constructed and
positioned along the tubular member 200 in a manner that is similar
to that which is described in commonly assigned U.S. Pat. No.
7,774,911 entitled "Method For Attenuating Driveline Vibrations",
the disclosure of which is incorporated by reference as if fully
set forth in detail herein. Briefly, the first damping device 250
can comprise a base or core 260 and a damping member 262. The core
260 can be formed of an appropriate structural material, such as a
lightweight fibrous material. For example, the core 260 can be
formed of two or more plies of paperboard or cardboard, wherein the
plies can overlie one another in a desired manner. In the example
provided, the core 260 is formed of paperboard and the plies are
helically wrapped.
[0034] The damping member 262 can comprise a length of an elastic,
rubbery material, such as ethylene propylene diene monomer (EPDM)
rubber or silicone rubber, having friction properties much greater
than those of the inside circumferential surface of the tubular
member 200. The damping member 262 can be fixedly coupled to the
core 260 and can extend radially outwardly therefrom where it can
terminate at one or more contact elements 264, such protuberances,
fingers, projections, that are configured to contact the inside
circumferential surface 228 of the tubular member 200. In the
particular example provided, the damping member 262 is generally
T-shaped, having a base 266, which is fixedly coupled to the core
260, and a contact element 264 that is shaped as a finger that
extends perpendicularly from the base 266. The damping member 262
can be secured to the core 260 in any desired manner. For example,
the damping member 262 can be bonded to the core 260 with a
suitable adhesive material such that the first damping member 262
extends helically about the core 260. With additional reference to
Figure--, the base 266 in the example provided is bonded to an
intermediate ply 270 of paperboard (i.e., a ply that is disposed
radially inwardly of the outermost ply 272 and radially outwardly
of the innermost ply 274) and the plys of paperboard that are
disposed radially outwardly of the intermediate ply 270 are wrapped
such that the sides of the material that forms the ply are abutted
against the damping member 262. In the example shown, the edges 280
of a first one of the plys 282 that is disposed radially outwardly
of the intermediate ply 270 are abutted against the sides 284 of
the base 266, while the edges 286 of the outermost ply 272 are
abutted against the sides 288 of the contact element 264 such that
the outermost ply 272 overlies the base 266 on its radially outward
side. The damping member 262 can extend over a desired portion of
the length of the core 260, such as substantially all of the length
of the core 260. The helical pitch of the damping member 262 can be
selected to provide a desired level of damping.
[0035] The third damping device 254 can be generally similar in its
construction to the first damping device 250 and as such, need not
be described herein in significant detail. In the particular
example provided, the first and third damping devices 250 and 254
are identical, but it will be appreciated that the third damping
device 254 can be configured somewhat differently from the first
damping device 250 to tune the damper 204 to a particular vehicle
10 (FIG. 1). It will be appreciated, for example, that various
characteristics of the third damping device 254 could be varied
from those of the first damping device 250 in order to achieve
desired performance of the damper 204, including the pitch of the
damping member 262, the direction of the helix of the damping
member 262, the configuration or number of damping elements--, the
length of the core 260 and the extent to which the damping member
262 extends over the length of the core 260.
[0036] The second damping device 252 can be formed of a suitable
damping material, such as a length of foam. In the particular
example provided, the second damping device 252 is a length of a
cylindrically-shaped closed-sell foam that can be formed of a
suitable material. Examples of suitable materials include
polyethylene; polyurethane; sponge rubber; PVC and vinyl nitrile
blends; PP and nylon foam blends; and melamine, polyimide and
silicone. It will be appreciated that various other materials, such
as an open-cell foam, or that one or more apertures could be formed
longitudinally through the second damping device 252. For example,
an alternately constructed second damping device 252' could be
formed with a plurality of longitudinally extending grooves 300 as
shown in FIG. 7. The grooves 300 can be configured to permit fluid
communication through the second damping device 252' when the
second damping device 252' is installed to a tubular member 200
(FIG. 4). The grooves 300 can be positioned about the circumference
of the second damping device 252' in a desired manner to affect the
balance of the propshaft assembly 20 (FIG. 1). For example, the
grooves 300 can be evenly spaced about the circumference of the
second damping device 252' to minimize the effect of the second
damping device 252' on the balance of the propshaft assembly 20
(FIG. 1). It will be appreciated that one or more of the second
damping devices 252' could be employed to damp a propshaft
assembly, with or without the first and/or third dampening devices
250 and 254.
[0037] The second damping device 252 can have an appropriate
density, such as between 1.0 pounds per cubic foot to 2.5 pounds
per cubic foot, preferably between 1.2 pounds per cubic foot to
about 1.8 pounds per cubic foot, and more preferably between 1.20
pounds per cubic foot to 1.60 pounds per cubic foot. In the
particular example provided, the second damping device 252 has a
density of 1.45 pounds per cubic foot. The second damping device
252 can be sized in a manner so that it is compressed against the
inside circumferential surface 228 of the tubular member 200 to a
desired degree. For example, the second damping device 252 can have
an outer circumferential diameter that is about 5% to about 20%
larger than the diameter of the inside circumferential surface 228
of the tubular member 200, and more preferably about 10% larger
than the diameter of the inside circumferential surface 228 of the
tubular member 200.
[0038] The damper 204 can be tuned for a particular vehicle
configuration in part by altering one or more characteristics of
the components of the damper 204, such as the positions of the
first, second and third damping devices 250, 252 and 254 relative
to the tubular member 200, the lengths of the first, second and
third damping devices 250, 252 and 254. In the particular example
provided, the first, second and third damping devices 250, 252 and
254 are spaced axially apart from one another along the
longitudinal axis of the tubular member 200. For example, the
second damping device 252 can be sized as long as possible without
contacting the first and/or third damping devices 250 and 254. It
will be appreciated, however, that the second damping device 252
could be sized in length to contact one or both of the first and
third damping devices 250 and 254.
[0039] The damper 204 can be installed to the tubular member 200 in
any desired manner. For example, the damper 204 can be pushed into
the tubular member 200 with a ram (not shown) contemporaneously
(i.e., sequentially, but in the same insertion cycle, for example
as with a single stroke of a ram) so that the first, second and
third damping devices 250, 252 and 254 abut one another.
Alternatively, the first, second and third damping devices 250, 252
and 254 can be installed to the tubular member 200 individually, or
the second damping device 252 can be installed to the tubular
member 200 contemporaneously with one of the first and third
damping devices 250 and 254. In situations where the first, second
and third damping devices 250, 252 and 254 are not installed
contemporaneously, one or more features can be incorporated into
the second damping device 252 to receive assembly tooling. For
example, a longitudinal slit 400 can be formed through the second
damping device 252. The longitudinal slit 400 permits a technician
to assemble the second damping device 252 onto a ram 402 having
retractable fingers 404 that extend from the ram 402 to abut an
axial end 406 of the second damping device 252. The ram 402 can be
pushed through the tubular member 200 in a first direction, the
second damping device 252 loaded onto the ram 200, the ram 200 can
be pulled into the tubular member 200 (i.e., moved in a second
direction opposite the first direction) to position the second
damping device 252 within the tubular member 200, the fingers 204
can be retracted and the ram 200 can be pulled out of the ram 200
(i.e, further moved in the second direction).
[0040] As another alternative, the first and third damping members
250 and 254 can be installed to the tubular member 200 to form an
intermediate sub-assembly, the intermediate sub-assembly can be
heat-treated to age the material that forms the tubular member 200,
and the second damping member 252 can be installed between the
first and third damping members 250 and 254 when the intermediate
sub-assembly has cooled sufficiently. It will be appreciated that
in this assembly method, the second damping member 252 can be
pushed through the first damping member 250 or the third damping
member 254 when it is positioned in the tubular member 200 between
the first and third damping members 250 and 254.
[0041] While the damper 204 has been illustrated and described as
comprising first, second and third damping devices 250, 252 and 254
that are formed as discrete components that are capable of being
separately installed to the tubular member, it will be appreciated
that the damper could be constructed somewhat differently. With
reference to FIG. 9, a damper 204' constructed in accordance with
the teachings of the present disclosure could be formed such that
the first, second and third damping devices 250', 252' and 254' are
fixed together so as to be capable of being inserted to the tubular
member 200 (FIG. 4) as a unit. For example, the cores 260 of the
first and third damping devices 250' and 254' could be portions of
a unitarily formed core member 500 and the second damping device
252' could be fixedly mounted to the core member 500 between the
damping members 262 of the first and third damping devices 250' and
254'. For ease of manufacture, the second damping device 252' could
be formed of a strip of foam that could be wrapped onto the core
member 500.
[0042] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
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