SCALABLE CRUSH CAN FOR VEHICLE
FIELD OF THE INVENTION
[0001] The present invention relates to a crush cans for vehicles, and more
particularly to a crush can that is scalable for use on a plurality of models of vehicles
having different masses, crush specifications and other parameters.
BACKGROUND OF THE INVENTION
[0002] Vehicle structures sometimes include an element referred to as a crush
can. The crush can is typically a member that mounts between the vehicle's bumper
and the vehicle frame, and provides a region for controlled energy absorption in the
event of a collision, so as to inhibit the collision energy from entering the passenger
cabin or damaging the vehicle frame. The crush cans used on vehicle structures
currently typically needed to be custom-designed for different vehicles particularly if
the different vehicles had different weights and/or different crush resistance
requirements. However having several custom-designed crush cans is costly in terms
of consuming technical resources and inventory.
[0003] It would be beneficial to provide a crush can configuration that was
easily scalable to fit different vehicles with different weights and different crush
resistance requirements.
SUMMARY OF THE INVENTION
[0004] In one aspect, the invention is directed to a crush can for a vehicle frame
including a crush can body having a longitudinal axis and a cross-sectional shape that is
at least approximately a 10-sided polygon.
[0005] In another aspect, the invention is directed to a crush can for a vehicle
frame including a crush can body having a longitudinal axis and a cross-sectional shape
that includes a plurality of outwardly pointing apexes alternating with a plurality of
inwardly pointing apexes.
[0006] In another aspect, the invention is directed to a crush can for a vehicle
frame including a crush can body having a longitudinal axis and a cross-sectional shape
that includes a plurality of outwardly pointing apexes and a plurality of inwardly
pointing apexes.
[0007] In another aspect, the invention is directed to a crush can for a vehicle
frame including a crush can body having a longitudinal axis and a cross-sectional shape
formed by a wall including at least two wall portions that abut each other. The wall
portions that are in abutment may optionally be joined together. The wall portions that
are in abutment may separate a first hollow shape, (eg. a central hollow shape) from a
second hollow shape (eg. a distal hollow shape). The central hollow shape may include
a plurality of apexes. The distal hollow shape may include one or more apexes.
[0008] In another aspect, the invention is directed to a method for forming a
crush can including: extruding a crush can body having a cross-sectional shape that
may include, for example, a central spine and a plurality of arms extending therefrom.
[0009] In another aspect, the invention is directed to a crush can for a vehicle
frame including a crush can body having a longitudinal axis and a cross-sectional shape
that is a non-hollow shape. The shape may include a central spine and a plurality of
arms extending from the spine. The shape may include a plurality of apexes therein. In
embodiments wherein the shape includes a central spine and a plurality of arms
extending therefrom, the apexes may be provided as bends in the arms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will now be described by way of example only
with reference to the attached drawings, in which:
[001 1] Figure 1 is a perspective view of a portion of a vehicle frame with two
crush cans thereon, which are in turn connected to a bumper, in accordance with an
embodiment of the present invention;
[0012] Figure 2 is a perspective view of one of the crush cans shown in Figure
i ;
[0013] Figure 3 is a perspective view of a crush can body from the crush can
shown in Figure 2;
[0014] Figure 4 is a sectional end view of the crush can body shown in Figure
3;
[001 5] Figure 5 is a side view of the crush can body shown in Figure 3;
[0016] Figure 6 is a perspective view of a crush can in accordance with another
embodiment of the present invention, wherein the crush can has a body that includes a
plurality of outwardly pointing apexes and a plurality of inwardly pointing apexes;
[0017] Figure 7 is a sectional end view of a crush can body from the crush can
shown in Figure 6;
[001 8] Figure 8 is a perspective view of the crush can body shown in Figure 7;
[0019] Figure 9 is a side view of the crush can body shown in Figure 7;
[0020] Figure 10 is a sectional end view of a crush can body in accordance with
another embodiment of the present invention, which includes a plurality of outwardly
pointing apexes and a plurality of inwardly pointing apexes, in a pattern of two
outwardly pointing apexes alternating with two inwardly pointing apexes;
[0021] Figure 11 is a sectional end view of a crush can body in accordance with
another embodiment of the present invention, which includes a plurality of outwardly
pointing apexes and a plurality of inwardly pointing apexes, wherein an odd number of
each type of apex is provided;
[0022] Figures 12-14 are sectional end views of crush can bodies in accordance
with other embodiments of the present invention, each of which includes a plurality of
outwardly pointing apexes and a plurality of inwardly pointing apexes;
[0023] Figure 15 is a sectional end view of a crush can body in accordance with
another embodiment of the present invention, which includes a central spine and a
plurality of arms extending therefrom, and which can be formed using an extrusion
process; and
[0024] Figures 16-18 are sectional end views of crush can bodies in accordance
with other embodiments of the present invention, each of which includes a wall,
portions of which are in abutment with each other.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Reference is made to Figure 1, which shows a crush can 10 for use in
absorbing collision energy during a vehicular collision. In the embodiment shown in
Figure 1, two crush cans 10 are provided between a vehicle frame shown at 12 and a
bumper shown at 25. Referring to Figure 2, the crush can 10 includes a crush can body
14, a front plate 16 and a rear plate 18. The crush can body 4 is shown more clearly in
Figure 3. The crash can body 14 has a longitudinal axis shown at 20. The longitudinal
body 14 has a cross-sectional shape that is shown in Figure 4. As can be seen in Figure
3, the cross-sectional shape is a 10-sided polygon. In a preferred embodiment, the
polygon is a regular polygon (ie. each of its 10 sides is the same width, and the angles
between adjacent pairs of sides are all the same (36 degrees). In other words, the
polygon in this embodiment is a regular decagon, albeit with rounded corners.
[0026] Referring to Figure 5, the crush can body 14 may be tapered axially.
The taper ratio for the crush can body 14 is the ratio of the cross-sectional dimension A
at the front end (shown at 22) of the crush can body 14, to the cross-sectional
dimension B at the rear end (shown at 24) of the crush can body 14. In embodiments
wherein there is a taper to the crush can body 4 as shown in Figures 2 and 4, one end
(eg. end 22) is a small end, and one end (eg. end 24) is a large end. The taper ratio may
be any suitable value. In the exemplary embodiment shown in Figures 1-5, the taper
ratio may be, for example, anywhere between about 0.5 (implying that dimension A is
½ of dimension B), and about 1 (implying that dimension A is the same as dimension B
which means that there is no taper).
[0027] As shown in Figure 1, the bumper 25 may be curved such that it is not
strictly perpendicular to the longitudinal axis 20 of the crush can 10. In order to
facilitate mounting of the crush can 10 to the bumper 25, the front end 22 (Figure 5) of
the crush can body 14 may be angled to generally match the sweep of the bumper 25.
[0028] With reference to Figure 3, the crush can body 4 may be made up of 10
planar forms 26 which meet at 0 apexes 28. The planar forms 26 make up the sides of
the polygon. It will be noted that the planar forms need not be strictly planar. The
apexes 28 in the embodiment shown in Figure 3 are all outwardly pointing apexes. The
apexes 28 of the polygon may be radiused depending on the method used to
manufacture the crush can body 14. In a preferred embodiment, the radius of each apex
28 may be between about 2 and 0 times the thickness of the wall of the crush can body
14. The wall thickness of the crush can 10 may be substantially constant along its
length, depending on how the crush can body 14 is manufactured. For example, in
some embodiments, the crush can body 14 may be made by first forming two clamshell
portions, shown at 29a and 29b in Figure 4. The two clamshell portions 29a and 29b
may each be formed from sheet material using a stamping machine, for example. The
two portions 29a and 29b may then be joined together, such as by a weld. In other
embodiments, the crush can body 14 may be formed by other methods, which would
result in a wall thickness that varies along the axial length of the crush can body 14.
For example, the crush can body 14 could be formed from a length of tubing that is
hydroformed so that it has the desired polygonal cross-sectional shape and the desired
taper. In such an embodiment, the wall thickness of the crush can body 14 would
decrease as the cross-sectional dimension increased. It can nonetheless remain that the
radius of each apex 28 is between 2 and 10 times the wall thickness, even if the wall
thickness varies along the length of the crush can body 4.
[0029] The crush can 0 may include one or more buckling features 30, which
may also be referred to as crush features. These features are positioned at a selected
position on the crush can body 4 so that buckling is initiated at the selected position
when the crush can 10 incurs a sufficiently large generally axially-directed compressive
force (eg. during a vehicular collision). As can be seen in Figures 3 and 5, the buckling
features 30 may all be positioned at the same axial distance from the rear end 24 of the
crush can body 4, such as at an axial position proximate the front end 22 of the crush
can body 14. The buckling features 30 may be up of lateral deformations of the apexes
28, however any suitable structure may be provided as the buckling features. The
lateral deformations that make up the buckling features 30 may be directed inwardly
(ie. towards the longitudinal axis 20) as shown in Figure 3. While buckling features 30
are provided at one particular axial position, it is possible to provide buckling features
30 at a plurality of axial positions.
[0030] The front and rear plates 16 and 18 are used to mount the crush can 10 to
the vehicle's bumper 25 (Figure 1) and to the vehicle frame 12 (Figure 1) respectively.
The front and rear plates 16 and 1 may be made from any suitable material (eg. steel)
in any suitable way (eg. stamping) may be joined to the crush can body 14 in any
suitable way such as by welding.
[0031] It has been found, surprisingly, that, for most bumper sweep angles the
10 sided crush can 10 provides better energy absorption than either an 8 sided crush can
or a 12 sided crush can of similar construction. It is theorized that as the number of
corners in the cross-sectional shape of the crush can body increases, the amount of
energy absorption that the crush can body is capable of increases. However, it is
further theorized that as the number of corners increases beyond a certain value (eg. 0
corners in a polygon wherein all the apexes are outwardly pointing), the crush can body
progressively resembles a body having a circular (more accurately, an annular) crosssectional
shape, which is theorized not have as much capability to absorb energy as a
shape having apexes.
[0032] It has been found that the crush can 10 is easily scalable in size and
strength to handle the energy absorption requirements for a large range of vehicle sizes
and weights. Some variables that can be controlled to assist in the scalability of the
crush can 10 include the material properties, the wall thickness, the cross-sectional
dimensions, the radius of curvature of the apexes and the taper ratio.
[0033] Reference is made to Figure 6, which shows a crush can 50 in
accordance with another embodiment of the present invention. The crush can 50 may
be similar to the crush can 10 (Figure 1), except that the crush can 50 includes a crush
can body 5 1 that has a different cross-sectional shape which includes both outwardly
pointing apexes 52 and inwardly pointing apexes 54, shown best in Figure 7. The
outwardly pointing apexes 52 and inwardly pointing apexes 54 alternate with each
other in the embodiment shown in Figure 7. Optionally, the crush can 50 includes
planar forms 56 between the apexes 52 and 54 and is thus a generally star-shaped
polygon, which is different than the polygon shape of the crush can body 1 shown in
Figure 4, which includes only outwardly pointing apexes 28. It has been found that the
8 pointed star shape shown in Figure 7 provides superior energy absorption to the 0
sided polygon shape shown in Figure 3. It will be noted that the cross-sectional shape
of the crush can body 5 1 provides a relatively large number of apexes 52, 54 while
having a relatively small cross-sectional dimension, which contributes positively to its
strength relative to its size and weight.
[0034] The radius of each of the apexes 52 and 54 may be any suitable radius,
such as, for example, between about 2 and 10 times the wall thickness of the crush can
body 51.
[0035] The crush can 50 may be fabricated in any suitable way. For example, a
single stamping made from a suitably shaped piece of sheet metal can provide the
undulations that ultimately form the apexes 52 and 54 in the finished crush can body
51. The stamping includes a first edge portion shown at 58 and a second edge portion
shown at 60 in Figure 7. The first and edge portions 58 and 60 may be joined together
in any suitable way. For example, as shown in Figure 7, the edge portions 5 and 60
may be overlapped by some amount and welded, thereby completing the crush can
body 51. Front and rear plates shown at 62 and 63 in Figure 6 may be joined to the
front end 64 and rear end 65 respectively of the completed crush can body 51. This
process for manufacturing the crush can body 5 1 results in a wall thickness that is
constant along its length. It will be understood that other manufacturing methods may
alternatively be used to make the crush can body 50, such as hydroforming, or such as
by welding two clamshell portions together.
[0036] As can be seen in Figure 8, the crush can body 5 1 includes buckling
features 66 which are made up by lateral deformations of the apexes 52 and 54. The
lateral deformations include inwardly directed lateral deformations 68 for apexes 52
and outwardly directed lateral deformations 70 for apexes 54. In the embodiment
shown in Figure 8, buckling features 66 are provided at three different axial positions
along the length of the crush can body 51, including a forward position proximate the
front end 64, a rearward position proximate the rear end 65 and a middle position
proximate the longitudinal middle of the crush can body 1. The longitudinal axis of
the crush can body 5 is shown at 72. Buckling features 66 are not provided along the
seam formed by the welded edge portions 58 and 60.
[0037] Similarly to the crush can body 14 (Figure 1), the crush can body 5 1 is
tapered and has a front cross-sectional dimension A (see Figure 9) at the front end
shown at 74, a rear cross-sectional dimension B at the rear end shown at 76, and a taper
ratio which is A/B which may be selected based on the crush resistance requirements of
the particular vehicle on which the crush can 50 will be used. The taper ratio may be,
for example, in the range of about 0.5 to about 1.
[0038] Also shown in Figure 9, is the angled plane of the front end 64 of the
crush can body 51 which may be provided to generally match the bumper sweep angle
of the bumper (not shown) to which the crush can 50 will be attached during use. It is
noted that the crush can body 5 1 shown in Figure 9 is shown with only one ring of
buckling features 66 instead of 3 rings of buckling features as shown in Figure 8.
[0039] In the embodiment shown in Figures 6-9, the crush can body 5 1 has a
cross-sectional shape of an 8 pointed star. It is alternatively possible to provide a shape
that has a different number of points. For example, the crush can body may have the
shape of a 6 pointed star, an example of which is shown at 80 in Figure 10. It will be
noted that the crush can body 80, comprises a alternating arrangement of two outwardly
pointing apexes 82a and 82b followed by two inwardly pointing apexes 84a and 84b.
[0040] In the embodiment described above, the crush can body had an even
number of outwardly pointing apexes and an even number of inwardly pointing apexes.
It is possible to provide a crush can body with an odd number of inwardly pointing
apexes and an odd number of inwardly pointing apexes, an example of which is shown
at 90 in Figure 11, which has 9 outwardly pointing apexes 92 and 9 inwardly pointing
apexes 94.
[0041] In other exemplary alternative embodiments, the crush can body may
have the cross-sectional shape of a 4 pointed star, as shown at 96 in Figure 12, a 5
pointed star as shown at 97 in Figure 13, or a 10 pointed star as shown at 98 in Figure
14. In each of these embodiments, the crush can body 80, 90, 96, 97 and 98 may be
tapered axially, similar to the tapering of the crush can body 14 in Figure 5. Each of
the crush can bodies 80, 90, 96, 97 and 98 can be provided with other similar features
shown for the crush can body 14 in Figure 5, such as buckling features, and a front end
that is angled to match the bumper sweep of the vehicle.
[0042] In another alternative embodiment, the crush can body may be an
extruded form, such as is shown at 100 in Figure 15. The extruded form is, in this
example, a non-hollow star shape, in contrast to the hollow shapes shown in Figures 1-
14. The non-hollow star shape includes a plurality of arms 101 (in this case 6), each of
which includes an apex shown at 102, and a central spine 104 from which the arms
extend.
[0043] In yet another alternative embodiment, the crush can body may be a
hollow star shape, as shown at 1 0 in Figure 16, but with a wall 112 that has portions in
abutment with other wall portions. Such portions are shown at 114. These abutting
wall portions 114 act as reinforcements for each other, serving to strengthen the crush
can body 10 and improve its energy absorption. Furthermore, these abutting wall
portions 114 separate the crush can body 110 into a plurality of hollow shapes. In the
embodiment shown in Figure 16, the abutting wall portions form arms 116, which
extend from a central hollow shape 118 and which have a hollow shape 120 at their
distal ends. The distal hollow shape 120 may be generally circular, as shown in Figure
16. The central hollow shape 118 may have a plurality of apexes therein, shown at 122
so as to improve the energy absorption of the crush can body 110. Immediately at the
proximal and distal ends of the abutting wall portions 1 4 apexes are provided, as
shown at 124a and 1 4b, and at 126a and 126b respectively.
[0044] In a variant of the embodiment shown in Figure 16, a crush can body
130 is shown in Figure 17, in which the central hollow shape shown at 132 is relatively
smaller and the arms, shown at 134 are relatively longer. Additionally, the distal
hollow shapes, shown at 136, at the ends of the arms 134 are shown having a generally
elliptical shape instead of a generally circular shape. At the distal ends of the ellipses,
an apex 138 may be said to be provided, in addition to the apexes associated with the
proximal and distal ends of the arms 134.
[0045] In yet another embodiment shown in Figure 18, a crush can body 140 is
shown having a generally small central hollow shape 142, however the arms, shown at
144 have relatively large distal hollow shapes 146 at their distal ends. The distal
hollow shapes 146 are shown having a generally triangular cross sectional shape
thereby including two apexes 148a and 148b in additional to the apexes associated with
the proximal and distal ends of the arms 144.
[0046] The above described shapes in Figures 16-18 may be roll-formed, or
may be formed by any other suitable means. The portions of the walls that are in
abutment with each other may be joined to each other or may be unjoined. If joined,
they may be joined by any suitable means.
[0047] While the above description constitutes a plurality of embodiments of
the present invention, it will be appreciated that the present invention is susceptible to
further modification and change without departing from the fair meaning of the
accompanying claims.
70791 2PCT
CLAIMS:
1. A crush can for a vehicle frame, comprising:
a crush can body having a longitudinal axis and a cross-sectional shape that is a
0-sided polygon.
2. A crush can as claimed in claim 1, wherein the 10-sided polygon is a regular
polygon.
3. A crush can as claimed in claim 1, wherein the 10-sided polygon is a decagon.
4. A crush can as claimed in claim 1, wherein the crush can body has a length and is
tapered along the length.
5. A crush can as claimed in claim 4, wherein the crush can body has a large end and
a small end, wherein, in use, the large end is rearward of the small end.
6. A crush can as claimed in claim 1, wherein the crush can body includes a first
clamshell portion and a second clamshell portion wherein the first and second clamshell
portions are welded together.
7. A crush can as claimed in claim , wherein the crush can body has a front end and
a rear end, and wherein the crush can further includes a front plate mounted to the front
end and a rear plate mounted to the rear end.
8. A crush can as claimed in claim 1, further comprising at least one buckling
feature positioned at a selected position along the crush can body to initiate buckling at
the selected position in the event of a sufficiently large axial compressive force on the
crush can body.
9. A crush can as claimed in claim 8, wherein the crush can body is made up of 10
planar forms that meet at 0 apexes, wherein the at least one buckling feature includes a
lateral deformation of at least one apex.
10. A crush can as claimed in claim 1, wherein the crush can body is made up of 10
generally planar forms that meet at 10 apexes.
1 . A crush can as claimed in claim 0, wherein the crush can body has a wall
thickness and wherein each apex has a radius that is between 2 and 10 times the wall
thickness.
12. A crush can as claimed in claim 4, wherein the crush can body has a wall
thickness that is substantially constant along the length of the crush can body.
13. A crush can for a vehicle frame, comprising:
a crush can body having a longitudinal axis and a cross-sectional shape that
includes a plurality of outwardly pointing apexes and a plurality of inwardly pointing
apexes.
14. A crush can as claimed in claim 13, wherein the cross-sectional shape is a
generally star-shaped polygon.
15. A crush can as claimed in claim 14, wherein the polygon is a regular polygon.
16. A crush can as claimed in claim 14, wherein the polygon has 6 outwardly pointing
apexes and 6 inwardly pointing apexes.
17. A crush can as claimed in claim 14, wherein the polygon has 8 outwardly pointing
apexes and 8 inwardly pointing apexes.
18. A crush can as claimed in claim 13, wherein the crush can body has a length and
is tapered along the length.
19. A crush can as claimed in claim 18, wherein the crush can body has a large end
and a small end, wherein, in use, the large end is rearward of the small end.
20. A crush can as claimed in claim 13, wherein the crush can body includes a first
edge portion and a second edge portion which are welded together.
21. A crush can as claimed in claim 13, wherein the crush can body has a front end
and a rear end, and wherein the crush can further includes a front plate mounted to the
front end and a rear plate mounted to the rear end.
22. A crush can as claimed in claim 13, further comprising at least one buckling
feature positioned at a selected position along the crush can body to initiate buckling at
the selected position in the event of a sufficiently large axial compressive force on the
crush can body.
23. A crush can as claimed in claim 22, wherein the at least one buckling feature
includes a lateral deformation of at least one apex.
24. A crush can as claimed in claim 13, wherein the crush can body has a wall
thickness and wherein each apex has a radius that is between 2 and 10 times the wall
thickness.
25. A crush can as claimed in claim 18, wherein the crush can body has a wall
thickness that is substantially constant along the length.
26. A crush can as claimed in claim 13, wherein the outwardly pointing apexes
alternate with the inwardly pointing apexes.
27. A crush can for a vehicle frame, comprising:
a crush can body having a longitudinal axis and a cross-sectional shape formed by
a wall and that includes a plurality of apexes, wherein at least two portions of the wall are
in abutment with each other.
28. A crush can as claimed in claim 27, wherein the at least two wall portions are
joined together.
29. A crush can as claimed in claim 27, wherein the at least two wall portions
together form an arm that separates a central hollow shape and a distal hollow shape.
30. A crush can as claimed in claim 29, wherein the central hollow shape has a
plurality of apexes.
31. A crush can as claimed in claim 29, wherein the distal hollow shape has at least
one apex.
32. A crush can for a vehicle frame, comprising:
a crush can body having a longitudinal axis and a non-hollow cross-sectional
shape including a central spine and a plurality of arms extending from the spine.
33. A crush can as claimed in claim 32, wherein each of the arms includes an apex
therein.
34. A method for making a crush can, comprising:
extruding a non-hollow cross-sectional shape including a central spine and a
plurality of arms extending from the spine.