U.S. patent application number 10/972139 was filed with the patent office on 2006-04-27 for snowmobile chassis.
Invention is credited to Jeremy L. Karnowski, Richard D. Kerner.
Application Number | 20060085966 10/972139 |
Document ID | / |
Family ID | 36204828 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060085966 |
Kind Code |
A1 |
Kerner; Richard D. ; et
al. |
April 27, 2006 |
Snowmobile chassis
Abstract
Vehicle chassis with effective load sharing joints and
reinforcing structure. The chassis of the invention use self
piercing rivets and other fabrication techniques to improve their
structural and performance characteristics. These improvements
result from, among other things, effective load distribution
through high-shear resistant fasteners and strengthening of
structural elements with reinforcing layers.
Inventors: |
Kerner; Richard D.; (Roseau,
MN) ; Karnowski; Jeremy L.; (Roseau, MN) |
Correspondence
Address: |
INTELLECTUAL PROPERTY GROUP;FREDRIKSON & BYRON, P.A.
200 SOUTH SIXTH STREET
SUITE 4000
MINNEAPOLIS
MN
55402
US
|
Family ID: |
36204828 |
Appl. No.: |
10/972139 |
Filed: |
October 22, 2004 |
Current U.S.
Class: |
29/524.1 ;
29/525.06 |
Current CPC
Class: |
B62D 29/001 20130101;
Y10T 29/49943 20150115; B62D 29/008 20130101; B62D 27/02 20130101;
B62D 23/00 20130101; Y10T 29/49956 20150115; B62K 19/26 20130101;
B62M 27/02 20130101 |
Class at
Publication: |
029/524.1 ;
029/525.06 |
International
Class: |
B21D 39/00 20060101
B21D039/00 |
Claims
1. A system for constructing a vehicle comprising: a. a first sheet
of material; b. a second sheet of material; c. a third sheet of
material of a different composition than at least one of the first
sheet of material or second sheet of material; and d. a self
piercing rivet, the self piercing rivet attaching the first sheet
of material and the second sheet of material to the third sheet of
material to form a joint that allows load sharing or structural
reinforcement of at least one of the first sheet of material or the
second sheet of material by the third sheet of material.
2. The system of claim 1, further comprising a fourth sheet of
material of a different composition than the third sheet of
material, wherein the fourth is attached to the first, second, and
third sheets of material by the self piercing rivet.
3. The system of claim 1, further comprising a fourth sheet of
material of the same composition than the third sheet of material,
wherein the fourth is attached to the first, second, and third
sheets of material by the self piercing rivet.
4. The system of claim 1, further comprising a second self piercing
rivet that attaches the first sheet of material and the second
sheet of material to the third sheet of material to reinforce the
joint.
5. A snowmobile comprising: a. a chassis including at least two
sheets of chassis material; b. an engine supported by the chassis;
c. at least one ski supported by the chassis; d. a steering column
operatively connected to the at least one ski for steering the
snowmobile; e. an endless track supported by the chassis and being
operatively connected to the engine; f. a third sheet of material
of a different composition than at least one of the sheets of
chassis material; and g. a self piercing rivet that attaches the at
least two sheets of chassis material to the third sheet of
material.
6. The snowmobile of claim 5, wherein the two sheets of chassis
material and the third sheet of material are formed at an angle
greater than 45 degrees proximate to the rivet.
7. The snowmobile of claim 5, wherein the third sheet of material
is formed at an angle greater than 45 degrees to reinforce the
chassis in two directions.
8. The snowmobile of claim 5, wherein the third sheet of material
reinforces the at least two sheets of chassis material.
9. A snowmobile chassis, comprising: a. first and second sheets of
chassis material being formed of aluminum; b. a third sheet of
chassis material being formed to reinforce the first and second
chassis sheets and of a material other than aluminum; c. a
self-piercing rivet joining together the first, second, and third
sheets of material to allow load sharing and structural
reinforcement of the first and second sheets of chassis
material.
10. The snowmobile chassis of claim 9, wherein the sheets of
chassis material are formed at an angle greater than 45 degrees
that provides reinforcement in two directions.
11. A snowmobile chassis, comprising: a. a suspension element; b. a
mount for attaching the suspension element to a chassis; c. a
chassis with at least two layers of overlapping chassis material
and a longitudinal chassis axis d. a self piercing rivet that
attaches the mount to the chassis and fastens together the at least
two layers of chassis material.
12. The snowmobile chassis of claim 11, wherein the suspension
element is oriented at a skew angle to the chassis axis.
13. The snowmobile chassis of claim 12, further comprising a
chassis element oriented generally transverse to the chassis,
wherein the self piercing rivet allows a load from the suspension
element to be redirected to the generally transverse chassis
element.
14. The snowmobile chassis of claim 12, further comprising a
chassis element oriented generally parallel to the axis of chassis,
wherein the self piercing rivet allows a load from the suspension
element to be redirected to the parallel chassis element.
15. The snowmobile chassis of claim 12, further comprising a
chassis element oriented at a skew angle to the longitudinal axis
of the chassis, wherein the self piercing rivet allows a load from
the suspension element to be redirected to the skew chassis
element.
16. A snowmobile chassis, comprising: a. a chassis comprising at
least one layer of chassis material; b. a heat exchanger
constructed of at least two layers of material; c. a self piercing
rivet that attaches the heat exchanger to the chassis by fastening
the heat exchanger to the at least one layer of chassis
material.
17. The snowmobile chassis of claim 16, wherein the heat exchanger
is constructed of at least three layers of material.
18. A system for attaching a tube to a chassis, comprising: a. a
tube having opposing, parallel sides, wherein a portion of the tube
is compressed so that the sides of the tube are adjacent to each
other; b. a chassis comprising at least one sheet of material; c. a
self piercing rivet that attaches the sheet of material to the tube
at the compressed portion of the tube by fastening the adjacent
sides of the tube to the sheet of material.
19. A method of constructing a snowmobile chassis, comprising: a.
fabricating a first chassis element formed of a sheet of material;
b. fabricating a second chassis element formed of a sheet of
material; c. layering the first chassis element, second chassis
element, and a reinforcing sheet of material of a different
composition than at least one of the chassis elements and
configured to reinforce at least one of the chassis elements; and
d. fastening the two chassis elements and the reinforcing sheet of
material together via a self-piercing rivet to form a joint, the
joint allowing load sharing and structural reinforcement of at
least one of the chassis elements.
20. The method of claim 19, wherein the reinforcing sheet stiffens
at least one of the chassis elements.
21. The method of claim 19, further comprising the step of layering
a second reinforcing sheet of material and riveting the two sheets
of reinforcing material and the two chassis elements together via a
self piercing rivet to form a joint.
22. The method of claim 19, wherein the layering of the first
chassis element, second chassis element, and the reinforcing sheet
of material results in a joint wherein the first chassis element,
second chassis element, and reinforcing sheet of material are
coextensive in the proximity of the joint.
Description
FIELD OF THE INVENTION
[0001] The present invention is related to vehicle chassis. More
specifically, the invention is related to a snowmobile chassis
constructed with the use of effective load sharing joints and
reinforcing structure.
BACKGROUND OF THE INVENTION
[0002] A vehicle chassis includes a vehicle's structural elements.
These elements may be attached to an underlying frame. In vehicles
with unitized or "unibody" construction, the chassis may
essentially comprise the frame and include everything but the
cosmetic body panels of the vehicle.
[0003] Vehicle chassis elements are frequently constructed of
relatively thin sheets of metal. Chassis elements must be
constructed to endure significant mechanical loads while being
lightweight and non-bulky to allow for flexibility in vehicle
construction.
BRIEF SUMMARY OF THE INVENTION
[0004] In one embodiment, the invention includes a system for
constructing a vehicle. This system may include a first sheet of
material, a second sheet of material, a reinforcing third sheet of
material, and a self piercing rivet. The reinforcing third sheet of
material may be of a different composition than at least one of the
first sheet of material or second sheet of material. The self
piercing rivet may attach the first sheet of material and the
second sheet of material to the third sheet of material to form a
joint that allows load sharing or structural reinforcement of at
least one of the first sheet of material or the second sheet of
material by the third sheet of material.
[0005] In another embodiment the invention includes a snowmobile
that includes a chassis made of at least two sheets of chassis
material, an engine supported by the chassis, at least one ski
supported by the chassis, a steering column operatively connected
to the at least one ski for steering the snowmobile and an endless
track supported by the chassis and being operatively connected to
the engine. This embodiment may further include a third sheet of
material of a different composition than at least one of the sheets
of chassis material. A self piercing rivet may attach the at least
two sheets of chassis material to the third sheet of material.
[0006] Yet another embodiment of the invention may include a
snowmobile chassis made of first and second sheets of chassis
material being formed of aluminum. This embodiment may further
include a third sheet of chassis material being formed to reinforce
the first and second chassis sheets and of a material other than
aluminum. A self-piercing rivet may join together the first,
second, and third sheets of material to allow load sharing and
structural reinforcement of the first and second sheets of chassis
material.
[0007] Another embodiment of the invention may include a snowmobile
that includes a suspension element, a chassis with at least two
layers of overlapping chassis material, a mount for attaching the
suspension element to the chassis, and a self piercing rivet that
attaches the mount to the chassis and fastens together the at least
two layers of chassis material.
[0008] Another embodiment of the invention may include a snowmobile
chassis that includes at least one layer of chassis material. The
embodiment also has a heat exchanger or other chassis element
constructed of at least three layers of material and a self
piercing rivet that attaches the heat exchanger or other chassis
element to the chassis by fastening the cooler to the at least one
layer of chassis material.
[0009] Another embodiment of the invention includes a system for
attaching a tube to a chassis. This embodiment includes a tube that
has opposing sides with a hollow passage between the sides. A
portion of the tube may be compressed so that the sides of the tube
are adjacent to each other. This embodiment also includes a chassis
comprising at least one sheet of material and a self piercing rivet
that attaches the sheet of material to the tube at the optionally
compressed portion of the tube by fastening the adjacent sides of
the tube to the sheet of material.
[0010] In another embodiment of the invention, a method of
constructing a snowmobile chassis includes fabricating a chassis
element, fabricating a second chassis element, positioning a first
layer of chassis material formed of aluminum, layering three sheets
of chassis material, two of the sheets being formed of aluminum,
one of the sheets being configured to reinforce the two aluminum
sheets and of a material other than aluminum, and riveting the
three sheets together via a self-piercing rivet to form a joint,
the joint allowing load sharing and structural reinforcement of the
two aluminum sheets of chassis material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a snowmobile in accordance
with an embodiment of the present invention.
[0012] FIG. 2 is a perspective view of an embodiment of a
snowmobile chassis in accordance with the invention.
[0013] FIG. 3 is a perspective view of an embodiment of a
snowmobile chassis in accordance with the invention.
[0014] FIG. 4 is a perspective view of an embodiment of a portion
of a snowmobile chassis in accordance with the invention.
[0015] FIG. 5 is a perspective view of an embodiment of a portion
of a snowmobile chassis in accordance with the invention.
[0016] FIG. 6 is a cross-section of the joint of FIG. 5 taken along
the direction indicated by the B arrows in FIG. 5.
[0017] FIG. 7 is a side plan view of an embodiment of a portion of
a snowmobile chassis in accordance with the invention.
[0018] FIG. 8 is a cross-section view of the embodiment of FIG. 7
taken from the perspective of arrow C in FIG. 7.
[0019] FIG. 9 is a cross-section view of an embodiment of a portion
of a snowmobile chassis in accordance with the invention.
[0020] FIG. 10 is a plan view of another embodiment of the
invention.
[0021] FIG. 11 is a cross-section of the embodiment of FIG. 10
taken along line A-A in FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The following detailed description should be read with
reference to the drawings, in which like elements in different
drawings are numbered identically. The drawings, which are not
necessarily to scale, depict selected embodiments and are not
intended to limit the scope of the invention. Several forms of the
invention have been shown and described, and other forms will now
be apparent to those skilled in art. It will be understood that
embodiments shown in drawings and described above are merely for
illustrative purposes, and are not intended to limit scope of the
invention as defined in the claims which follow.
[0023] In the construction of vehicle chassis, it can be useful to
employ structural elements formed of relatively thin sheets of
material. These elements may, for example, be a beam-like structure
that is subjected to any one of, or a combination of, torsional,
tensile, compressive or bending loads. Chassis elements may be
fabricated by stamping or otherwise cutting the element from a
sheet of stock material. Elements may also be fabricated by bending
or forming a sheet of material to a desired shape. The chassis may
also be fabricated by welding, riveting, bolting, or otherwise
fastening constituent chassis elements together to form the desired
structure.
[0024] Various construction techniques exist to build such an
element that is strong enough to withstand the forces acting on it
when used in a vehicle chassis. A box section, where the sheet of
material is formed into a beam with a box-shaped cross-sectional
frame structure can be formed to strengthen the element. I-section
and C-sections, which look like these respective letters in
cross-section, are other structures that may be used to create
stronger chassis elements from sheets of material. However, these
structures may require additional material, increasing vehicle
weight and expense, and may take up valuable space that could
otherwise be used for other vehicle components.
[0025] One construction technique to strengthen load bearing
elements constructed of one or more sheets of material without
necessarily creating bulky structures is to attach a layer of
reinforcing material to the base sheet or sheets of material to
increase its cross-sectional thickness and load bearing capability.
Prior art means of attaching these reinforcing layers such as
welding, for example, can dramatically reduce the materials'
strength through heat damage. It is believed, for example, that the
aluminum alloy commonly referred to as Aluminum 5052-H34 has a
yield strength reduction of approximately 54% from 31,200 psi to
13,000 psi in the heat affected zone after welding. It should be
noted that these heat impacts are localized near any welded seams,
which may be the area intended to be strengthened.
[0026] In one embodiment of the invention, a reinforcing material
is attached to a chassis formed of two or more layers of base
material using one or more self piercing rivets. This construction
method has the advantage of having minimal impact on the strength
of the underlying and reinforcing sheet or sheets of material as
compared to welding.
[0027] Attaching a reinforcing layer using a self piercing rivet
may also be superior to using traditional fasteners that require
predrilled holes. Holes formed in the sheets of material for these
fasteners are slightly larger than the fasteners themselves,
creating "play" between the fastened sheet of metal and the
fastener.
[0028] Further fasteners that require predrilled holes,
particularly traditional rivets but also many threaded fasteners,
may be more likely to fail under shear stresses. Shear stress is
stress transverse to the length of the fastener that may be applied
when two or more sheets of material joined by the fastener are
subjected to forces oriented parallel to the surfaces of the sheets
of material. Shear stress can be more easily envisioned as a force
that is attempting to cut the fastener transversely.
[0029] The self piercing rivet may also have higher shear strength
than many conventional rivets that require predrilled holes. Also,
conventional fasteners that require predrilled holes, whether
rivets or threaded fasteners, may have problems with the holes
expanding creating "play" or "slop" in the joint. This problem
increases as more layers of material are joined because the holes
for the fasteners must be typically larger to allow for alignment
of the holes through each of the several layers of material.
Additionally, vibration or movement between the layers of material
may cause the holes to widen as the material contacts the
fastener(s). By using self piercing rivets, alone or in conjunction
with other fastening techniques, the inventor has overcome
limitations in prior art chassis manufacturing.
[0030] A snowmobile 10 in accordance with an embodiment of the
present invention is shown in FIG. 1. Generally, snowmobile 10
includes a longitudinally extending chassis 20 having a front
portion 22 and a rear portion 24. The chassis 20 supports and
mounts several vehicle components, including an engine, a seat 36,
a drive track 46, a pair of steerable skis 54, and a body assembly
56. In some embodiments, the chassis 20 supports the engine
proximate the front portion 22 and the seat 36 proximate the rear
portion 24. The seat 36 is adapted to accommodate a rider in
straddle fashion, and the engine powers the drive track 46
operatively connected to the chassis 20 proximate the rear portion
24. Means for supporting a rider's feet extending longitudinally
below opposite lateral sides of the seat 36 may be provided. In
some embodiments, the means may include footrests 50 that extend
longitudinally below opposite lateral sides of the seat 36. The
chassis front portion 22 may be suitable for mounting the pair of
steerable skis 54 and supporting the body assembly 56. The body
assembly 56 may contain the engine. A steering post 58 is
operatively connected to the pair of skis 54. Means for rotating
the steering post 58 to effect steering may be provided, and the
means for rotating may be supported by the steering post 58. In
some embodiments, the means for rotating may include a steering
control, such as handlebars 60, supported by the steering post
58.
[0031] In the exemplary snowmobile shown in FIG. I the steerable
skis 54 may be attached to a front suspension system 62 that
includes an A-arm or wish-bone, henceforth referred to as an A-arm
64 component. The A-arm 64 is pivotally mounted on an A-arm mount
66 that is affixed to the front portion of the chassis 22. The
A-arm 64 can be generally referred to as a suspension element. A
suspension element can be any structural element that connects the
frame or chassis to the components of the vehicle that contact the
ground during operation. Suspension elements are typically movable
relative to the chassis or frame and may be connected to a shock
absorber assembly that may contain a form of spring and/or a shock
or other damping element that controls the rate and quality of this
movement. A suspension system other than the A-arm suspension
system, such as a trailing arm or strut-type suspension system, may
be used without departing from the scope of the invention.
[0032] The vehicle chassis 20 has a longitudinal axis that runs
from the front portion 22 of the chassis to the rear portion 24 of
the chassis essentially along a line that bisects the chassis.
[0033] FIG. 2 is a perspective view of an embodiment of a
snowmobile chassis 20 of the invention with the front suspension
62, drive track 46, and steering post 58 installed. The chassis has
a rear portion 24 and a front portion 22. A front suspension 62
suspends a pair of steerable skis 54 from the chassis 20. The front
suspension 62 includes two pairs of A-arms 64 that are pivotally
mounted on the chassis 20 by A-arm mounts 66. The steerable skis 54
are operatively attached to a steering post 58 that may be turned
by the operator using handlebars 60. The chassis includes footrests
50. Also visible in FIG. 2 is a rear heat exchanger 26 and a heat
exchanger connecting tube 28 mounted near the top rear of the
chassis.
[0034] FIG. 3 is a perspective view of an embodiment of a chassis
of the invention. FIG. 3 more clearly shows elements of the chassis
that may use the self piercing rivet to reinforce structural
elements, distribute stress loads, and join members. For instance
the A-arm mounts 66 are fastened to the chassis 20 using
three-layer self piercing rivets as shown more clearly in FIGS. 4-6
and described further below. Also a localized steel reinforcement
plate 70 is shown attached to the chassis 20 and is shown more
clearly in FIG. 7 and described further below.
[0035] FIG. 4 is a perspective view of a portion of an embodiment
of a chassis in accordance with the invention. The chassis region
shown in FIG. 4 is proximal to the front suspension upper A-arm
mounts 66. This portion of the chassis 20 includes two layers of
chassis material 90 layered in an overlapping fashion. The A-arm
mounts 66 are affixed to the chassis using one or more three-layer
self piercing rivets 80. The use of the self piercing rivet 80
allows for secure attachment of potentially dissimilar materials.
While other fastening means such as predrilled fasteners or welding
may be used in conjunction with the self piercing rivet 80, the
self piercing rivet 80 does not weaken the underlying material as
may happen with welding due to heat damage. Also the fastening of,
for example, steel sheets to aluminum chassis sheets is
significantly difficult, if not impossible, through conventional
welding techniques, while the self piercing rivet will effectively
fasten dissimilar materials.
[0036] FIG. 5 is a perspective view of a portion of an embodiment
of a chassis in accordance with the invention. The chassis region
shown in FIG. 5 is proximal to the front suspension rear lower
A-arm mount 66. In this figure, a layer of metal is not shown to
allow for easier display of the joint. There are two layers of
chassis metal 90 (one not shown) layered in an overlapping fashion.
The A-arm mount 66 is attached to the chassis using one or more
three-layer self piercing rivets 80. The A-arm 64 (shown in FIG. 2)
that is mounted on this mount is oriented at a skew angle relative
to the chassis 20.
[0037] A chassis cross-member 92 configured in this example as a
U-channel is oriented generally transverse to the main chassis 20.
The load or force applied along arrow A is skew or at an angle not
perpendicular to the chassis 20. The joint formed by the
three-layer self piercing rivets 80 of this embodiment of the
invention transmit this force to the transverse chassis cross
member 92. The self piercing rivets 80 help form a joint that is
strong enough to redirect the angled force to the chassis cross
member 92, which is a stronger member due to its U-shaped
configuration, among other factors. This joint can easily be
constructed with the use of self piercing rivets which have the
advantages described above, among others.
[0038] Arrow A indicates a load or force applied to the lower rear
A-arm mount 66 in a direction generally parallel to the lower rear
A-arm 64 (shown in FIG. 2). Loads transmitted from the ground
through the steerable ski and front suspension to the A-arm must be
redirected from this skew angle A to transverse angle B so that the
U-channel chassis cross-member 92 can share the load. The
three-layer self piercing rivets 80 used to attach the A-arm mount
66 to the chassis 20 allow for the redirection of this load from
angle A to angle B because of their high shear strength. There is
no requirement that the chassis cross-member be configured as a
U-channel, and the three-layer self piercing rivet may be used to
redirect forces within the chassis to or from chassis elements of
any shape by taking advantage of the high shear strength and other
advantageous attributes of the self piercing rivet.
[0039] This application of the self piercing rivet takes advantage
of the self piercing rivet's ability to carry a significant load in
shear. The force oriented along the arrow A exerts a shear force
generally transverse to the self piercing rivets 80. These
fasteners can withstand this load and effectively transfer it to
the reinforcing layer (not shown) and the chassis 20 through the
cross member chassis element 92.
[0040] FIG. 6 is a cross-section of the joint of FIG. 5 taken along
the direction indicated by the B arrows in FIG. 5. This cross
section shows the cross member chassis element 92, the A-arm mount
66, and two layers of the chassis material 90. The cross member
chassis element is formed at region 94 to provide reinforcement in
more than one direction. The self piercing rivets 80 secure the
chassis element 92 to the chassis 20 one either side of formed
region 94 to provide reinforcement and support to the chassis 20 in
more than one direction.
[0041] FIG. 7 is a side plan view of a portion of an embodiment of
a snowmobile chassis in accordance with the invention. The chassis
20 of this embodiment is made of an aluminum alloy and a
reinforcing layer 70 is made of steel. A second layer of aluminum
(not shown) is on the other side of the chassis 20. The reinforcing
layer 70 is fastened to the chassis material 90 and the second
layer of aluminum by one or more self piercing rivets 80. The
reinforcing layer 70 and the second layer of aluminum provide
additional strength and stability to chassis 20 without
significantly increasing the size of the chassis structure in the
area. The use of the self piercing rivets 80 for this purpose may
reduce or eliminate the need for welding, which is advantageous
because welding can reduce the strength of the chassis material 90
or reinforcing layer 70 by heating and weakening the material.
[0042] The use of self piercing rivets may also reduce or eliminate
the need for fasteners that require predrilled holes in the chassis
20 and/or the reinforcing material 70. This may reduce production
time and costs. Also, these fasteners frequently can become loose
as the tolerance or gap between the fastener and the hole through
which the fastener is placed expands over time.
[0043] FIG. 8 is a cross-section view taken from the perspective of
arrow C in FIG. 7 of the reinforcing layers of the chassis 20. The
steel reinforcing layer 70 is shown oriented to the outside of the
two layers of chassis material 90, although the layers may be
placed in any order or orientation. The three-layer self piercing
rivets secure the dissimilar materials for reinforcement of the
chassis without the need for welding or pre-drilled holes. This
reinforcement layer requires less space than previous structural
reinforcement techniques such as C-sections, box-sections and the
like.
[0044] FIG. 9 is a cross section of an embodiment of the invention.
In this embodiment, self piercing rivets 80 are used to secure a
three layer heat exchanger 26 to the chassis 20 by fastening the
heat exchanger 26 to a layer of chassis material 90. The region of
the chassis shown is generally the rear portion 24. The heat
exchanger connecting tube 28 supplies and returns fluid to and from
the heat exchanger 26. All of the material being attached by the
self piercing rivets 80 in this embodiment is aluminum, but due to
the fine tolerances present in the heat exchanger 26 and the
relative thinness of the material, the self piercing rivet 80
allows for attachment of the heat exchanger 26 to the chassis 20
without the heat damage potentially associated with welding, for
example. The self piercing rivet also allows for a tight tolerance
secure attachment that reduces the potential for vibration damage
to the heat exchanger 26. The self piercing rivet also allows for
attachment of the heat exchanger 26 without pre-drilling holes in
the heat exchanger 26 and the attendant costs and potential for
manufacturing errors that could result in destruction of the heat
exchanger 26. While certain materials of construction are described
in association with disclosed embodiments of the invention, it
should be understood that other materials of construction
including, but not limited to, metals and metal alloys, polymers,
reinforced polymers and composite materials may be used without
departing from the spirit of the invention or the scope of the
claims.
[0045] The heat exchanger 26 or similar element that is attached to
the chassis 20 by the self piercing rivet 80 may provide structural
integrity to the chassis in a manner similar to the other
reinforcing and load sharing joints described herein. In other
words, in addition to providing a superior mounting of the heat
exchanger 26 to the chassis 20, the self piercing rivet 80 and
systems and methods of the invention may use elements mounted to
the chassis to reinforce the chassis.
[0046] FIG. 10 is a plan view of another embodiment of the
invention. In this embodiment a tube 100 is attached to a sheet of
material 30 by self piercing rivets 80.
[0047] FIG. 11 is a cross-section of the embodiment of FIG. 10
taken along line A-A. In this view it is clear that the tube 100 is
compressed so the top wall 110 and bottom wall 120 of the tube are
flattened against one another and oriented approximately coplanar
with the bottom wall 120 of the tube. The self piercing rivet 80
attaches the tube securely to the sheet of material 30 as described
above. This is superior to the traditional method of construction
of a tube to a sheet, i.e. welding or bolting. Multi-layer self
pierce riveting offers the advantage of a simple, low cost, rigid
joint without the side effects of welding or preformed or drilled
holes.
[0048] While exemplary embodiments of this invention and methods of
practicing the same have been illustrated and described, it should
be understood that various changes, adaptations, and modifications
may be made therein without departing from the spirit of the
invention and the scope of the appended claims.
* * * * *