FIELD OF INVENTION
This invention relates to an assembly of front bumper.beam and reinforcement
design with variable cross-section in a vehicle for improved resistance to
impact force.
BACKGROUND /PRIOR ART OF INVENTION
Conventional assembly of front bumper beam and reinforcement in a vehicle is
illustrated in fig. 1 wherein the reinforcement (1) has uniform cross section,
which is located behind bumper beam (2).The uniform configuration of
reinforcement leads to weak front bumper. assembly. This results in high
deformation which can lead to damage of functional components such as
radiator, condenser etc when tested as per the regulation for low speed impact.
Hence it is difficult to meet regulatory requirement.
in order to obtain the bumper beam assembly with variable cross section either
roll forming or extrusion process is adopted. Fig. 1A illustrates roll formed 85
extruded bumper beam assembly. Roll forming is costlier operation as
compared to stamping process as to produce a variable cross sectional shaped
beam it requires secondary operations which involves higher cost. Another
method to produce variable cross section beam is extrusion. Extrusion is
mostly performed for manufacturing of Aluminum bumper beam assembly,
wherein the Aluminum bumper beam assembly has huge impact on cost.
Some Patents/Publications may be discussed hereinbelow:
A known technology consists of an energy absorber adapted for attachment to
a vehicle for absorbing forces generated from an impact. Said energy absorber
comprising a unitary structure having a molded mat of fiber reinforced resin
material, and also having a crushable forward projecting portion adapted to
crush upon impact. The energy absorber is combined with a fascia and a
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reinforcing beam with the energy absorber inter-disposed to form a bumper
system for automotive vehicles.
Thus, it is directed to energy absorber located in front of beam assembly
mainly to absorb pedestrian leg impact energy. It is having conical cross
section with the provision of beads on the flanges, which can result in stress
concentration, this may in turn affect its durability performance. Further, it is
made by injection molding (thermoplastic part) which is costlier.
A bumper system for a vehicle comprising: a beam adapted for attachment to a
vehicle and an energy absorber engaging a face of the beam. The energy
absorber having a top horizontal section defined by a top wall and an uppermid
wall connected by an upper-front wall, and having a bottom horizontal
section defined by a bottom wall and a lower-mid wall connected by a lowerfront
wall, and further having a middle horizontal section defined by a midfront
wall connecting the upper-mid wall and the lower-mid wall, the top and
bottom horizontal sections including top and bottom front nose portions that
extend forward of the mid-front wall and that define a horizontal channel
therebetween in front of the mid-front wall.
The front nose portions are configured to provide a first level of energy
absorption during an initial impact stroke that collapses one or both of the
front nose portions, and the top, middle, and bottom' horizontal sections
provide a higher second level of energy absorption during a continuing impact
stroke that collapses the energy absorber against the face of the beam; and
a fascia covering the energy absorber and the beam.
A bumper system for a vehicle comprising: a beam adapted for attachment to a
vehicle and having a longitudinal curvature that, when viewed from above in a
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vehicle-mounted position, is shaped to match an aerodynamic curvilinear
shape of a front of the vehicle. There is provision of
an energy absorber attached to a face of Lhe beam wherein the energy absorber
having a top horizontal section defined by a top wall and an upper-mid wall
connected by an upper-front wall, and. having a bottom horizontal section
defined by a bottom wall and a lower-mid wall connected by a lower-front wall.
The top and bottom horizontal sections including top and bottom front nose
portions extend forwardly. The top and bottom nose portions each being semirigid
but collapsible with a parallelogram motion that shifts one or both of the
top and bottom front walls vertically, such that horizontal impact forces are
converted at least in part to a vertical force "upon receiving a horizontal frontal
impact during an initial stroke of the frontal impact.
It is related to an energy absorber with B-shaped cross section in front of beam
assembly in order to absorb pedestrian leg impact energy. It is made by
injection molding which is expensive.
Another known art provides a reinforcement main unit comprising a long
scaled panel having substantially a U-shaped section over the entire length. In
a surface of the opposed panel in both end parts of this reinforcement main
unit, by forming a plurality of protrusive streak parts divergent toward an
opening side of the panel, a curved part is formed in the both end parts of the
reinforcement main unit.
In a surface of the opposed panel in an intermediate part except the both end
parts of the reinforcement main unit, multiple parallel beads, which can
control buckling load resistance, are formed.
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In the above, cross section of reinforcement does not have corrugation rather it
has V-shaped beads on the top and bottom flange of the reinforcement. This
may result in high stress concentration, which can lead to less durability of
beam assembly.
hi view of the above, it is required to have a provision to counter the high
deformation b}' strengthening assembly of bumper beam and reinforcement for
limiting the deformation of front bumper assembly within permissible limits,
which can be manufactured at a low cost.
OBJECTS OF THE INVENTION
The principal object of the present invention is to provide an assembly of front
bumper beam and reinforcement in a vehicle for improved resistance to impact
force which overcomes shortcomings associated with the prior art(s).
Another object of the' present. invention is to provide an assembly of front
bumper beam and reinforcement in a vehicle for. improved resistance to impact
force which is simple in construction and efficient.
Still another object of the .present invention is to provide an assembly of front
bumper beam and reinforcement in a vehicle for improved resistance to impact
force which is capable of absorbing impact energy efficiently in case of low
speed bumper impact.
SUMMARY OF THE INVENTION
According to this invention, there is provided an assembly of front bumper
beam and reinforcement in a vehicle for improved resistance to impact force
comprises front bumper beam spot-welded with a laterally extended
reinforcement having corrugated profile with variable cross-section.
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BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings of exemplary embodiments of invention and wherein:
Fig. 1 shows: Conventional front bumper beam and reinforcement
assembly;
Roll formed & extruded bumper beam assembly;
Layout of front bumper assembly;
Cross sectional view of bumper beam and reinforcement
assembly according to present invention;
Isometric view of reinforcement of present invention
indicating various flanges thereof;
Isometric view of Asymmetrical mid flanges of reinforcement;
Fig4B & 4C shows: Sectional view of Asymmetrical mid flanges of reinforcement
representing variable cross section;
Isometric view of Flat face of flanges at each side;
Corrugated profile of reinforcement;
Front view of bumper beam & reinforcement assembly;
Isometric view of reinforcement;
Sectional view of reinforcement representing variable cross
section;
A plot between Time(s) (X-axis) and Energy absorption (J)
reflectingenergy absorption comparison of reinforcement of
new design ( ) and existing design ( );
Fig. 1A shows:
Fig. 2 shows:
Fig. 3 shows:
Fig. 4 shows:
Fig. ,4A shows:
Fig. 4D shows:
Fig. 5 shows:
Fig. 6 shows:
Fig. 7 shows:
Fig. 8 shows:
Fig. 9 shows:
Fig. 10 shows:
Fig. 11 shows:
Results of the existing design 10(a) in dynamic condition and
10(b) post test;
Results of the new design of invention 11(a) in dynamic
condition and 11(b) post test;
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Fig. 12 shows: A plot between displacement (mm) (X-axis) and Reaction
force (KN) reflecting Reaction Force vs Displacement
comparison of new design ( ) and existing design ( );
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS
The invention consists, of- teaching regarding an assembly of front bumper
beam and reinforcement in a vehicle for improved resistance to impact force.
For general layout of front bumper beam assembly, reference may be made to
fig. 2 indicating functional component (1) behind bumper beam and
reinforcement assembly (2) placed next to front bumper (3). Here, bumper
beam and reinforcement assembly (2) is arc welded to crash box (4) which is
then bolted to side rails (5). Key function of front bumper
beam and reinforcement assembly in low speed front bumper impact is to
safeguard the functional components such as radiator, condenser, horn,
hood-latch, lightning &signaling devices.
The invention introduces, an improved version of bumper beam and
reinforcement assembly which is capable of absorbing the impact energy
efficiently in case of low speed bumper impact.
The assembly comprises a specially devised reinforcement in connection with
front bumper beam. Thus, the invention focuses on novel design of
reinforcement.
Now reference may be made to fig. 3, wherein the reinforcement member (1) is
extended laterally and placed rearward of bumper beam (2). The reinforcement
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has a variable cross-section throughout its length. The length of reinforcement
is preferably less than that of the bumper beam.
The reinforcement constitutes a single piece as illustrated in fig. 4.Said
reinforcement comprising of a plurality of flanges including a flanges (3,4) at
each side i.e. at top and bottom and atleast two mid flanges (5,6) as seen in
the figure.
All the aforesaid flanges are integrated to each other to form the single piece.
The flanges (3,4) at each side can have flat face (fig: 4D),alternatively which
can be curvy (fig. 4) for spot welding with the bumper beam (2).
The mid flanges (5,6) are corrugated with ridges (7) and grooves (8) as in fig.
5. The pitch and depth of the corrugated profile can be variable according to
the bumper beam design. According to one embodiment, mid flanges are
mirror images of each other as in fig. 4, wherein the mid flanges are
preferably symmetrical with respect to each other to facilitate
manufacturing. According to another embodiment, asymmetrical mid flanges
can also be provided as best seen in fig. 4A ,4B &4C.
Thus the reinforcement is designed with corrugated profile to increase the
stiffness of bumper beam assembly. • .
The detailed representation and sectional views of reinforcement are as
shown in the figures 6, 7 and 8.
The bumper beam and reinforcement assembly can be manufactured using
stamping operations. In this invention Cold rolled low strength steel can be
used for both bumper beam and reinforcement assembly without restricting
scope of invention to the same. It is possible to manufacture the part with
high strength steel which can amplify the strength characteristics of
I P O DELHI 2 6- - OS - 2 Ol B 1 ?: i 1 I
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bumper beam, and reinforcement assembly. However the choice of material
is dependent upon the factors such performance, cost, weight and layout.
Reinforcement with corrugated profile had shown improved resistance to the
impact force. The projected profile of reinforcement supports the bumper beam
resulting in increased bending stiffness. The stiff structure of bumper beam
and reinforcement absorbs the impact energy through plastic deformation and
hence prevents the damage to • functional components of the vehicle, which
includes lightning, signaling &safety related components. As per regulation for
low speed impact, vehicle's cooling systems, lightning & signaling devices
should remain functional when tested at velocity of 4 Kmph.
The present design of reinforcement possesses excellent energy absorption
capacity as shown in Fig.9. The energy absorption comparison is made with
currently evaluated design of reinforcement.
Thus, the unique cross-sectional shape of bumper beam 86 reinforcement
assembly enhances the strength of the assembly. The sectional modulus
of the reinforcement is considerably high imparting the bumper beam
&reinforcement assembly desired stiffness against bending. In addition to this,
the corrugated structure of bumper reinforcement acts as a bead in case of
axial loading 8& provides the additional stiffness. The increased strength of
bumper beam and reinforcement assembly gives rise a part with lesser gauge,
leading to considerable saving in cost 8& weight.
Reference may be made to fig. 10(a) showing the following:
Barrier-1
Condenser-2
Hitting is observed-3
Bumper Beam-4
Reinforcement-5 - .
and Fig. 10(b) showing the following:
Condenser-2'
Post test gap=xmm-3'
Bumper Beam-4'
Reinforcement-5'
Further reference may be made to fig. 11(a) indicating the features
hereinbelow:
pa MLHI.H-&e-20l? I.? -II
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Barrier-1
Condenser-2
Minimum dynamic gap=no hitting3
Bumper beam-4
Reinforcement-5
and fig. 11(b) indicating the post test gap of 5xmm(3')
Again, fig. 12 reflects reaction force Vs displacement comparison.
Advantageous Features
- Highly stiffened front bumper beam and reinforcement assembly
- Efficient absorption of the impact energy in case of low speed bumper
impact •
- Effective safeguarding of the functional components such as a radiator,
condenser, horn, hood-latch, lightning & signaling devices in low speed
front bumper impact.
- Enhanced strength of bumper beam and reinforcement assembly gives
rise a part with lesser gauge leading to considerable saving in cost and
weight.
- Corrugated profile and variable cross section of reinforcement provides
the required balance between strength and weight.
It is to be noted that the present invention is susceptible . to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims:- . •
I PO DELHI 2&-Q6--201E-. 17

We Claim:
1. An assembly of front bumper beam and reinforcement in a vehicle for
improved resistance to impact: force comprises front bumper beam in
connection with a laterally extended reinforcement having corrugated
profile with variable cross-section.
2. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in claim 1 wherein the beam is placed in front of the laterally
extended reinforcement having a variable cross-section throughout its
length and length of which is preferably less than that of the beam.
3. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in claim 1 or 2 wherein the reinforcement comprises multitude of
flanges including a flange at each side and atleast two mid flanges.
4. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in claim 3 wherein said flanges are integrated to constitute a
single piece of the reinforcement.
5. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in any of the preceding claims wherein the flange at each side
can be provided with a flat face, alternatively which can be curvy face for
establishing connectivity with the beam.
6. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in any of the preceding claims wherein said mid flanges are
corrugated with ridges and grooves.
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7. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in any of the preceding claims wherein the mid flanges can be
symmetrical with respect to each other.
8. An assembly of front bumper.beam and reinforcement in a vehicle as
claimed in any of the preceding claims wherein the mid flanges can be
asymmetrical with respect to each other.
9. An assembly of front bumper beam and reinforcement in a vehicle as
claimed in any of the preceding claims is associated with the
advantageous features such as herein described.
10. An assembly of front bumper beam and reinforcement in a vehicle
for improved resistance to impact force substantially as.herein described
with reference to the accompanying drawings.