CRASH BOX STRUCTURE FOR ABSORBING IMPACT ENERGY DURING VEHICLE COLLISION
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to an impact energy absorber for front end of vehicle, and, in particular, to a structure of crash box for 5 front bumper of the vehicle to absorb impact energy during vehicle collision. More particularly, to a plastically deformable structure of crash box during vehicle collision to absorb impact energy. In more specifically, the present subject matter relates to a structure of a crash box at the front end of the vehicle to absorb impact energy so efficiently to avoid serious injuries to pedestrian during collision 10 with the vehicle.
BACKGROUND AND PRIOR ART:
[002] Generally, front bumper BIW systems are used to absorb impact energy of the collision and to protect the vehicle body in the event of an impact at low speed against structural damage. Further, the front bumper also protects pedestrians 15 from injuries when the pedestrian collides with vehicle. The bumper has a rigid crossbeam installed across width of the vehicle and connected to left and right side rails via crash boxes, respectively. The crash boxes receive the impact energy during collision from the bumper cross beam. The crash boxes absorb the impact energy to reduce the amount of damage on the vehicle. Generally, the crash boxes 20 are designed to protect the vehicle body and occupants of the vehicle.
[003] Fig. 1 illustrates the structure of existing crash box. The crash boxes are installed on the left and right side of the bumper cross beam across the width of the vehicle. The crash boxes are provided on the front and rear end of the vehicle behind the bumpers. 25
[004] On the rear side, the crash boxes are joined with the front cross member plate which is mounted on the front long members of the vehicle. Whereas the bumper crossbeam is attached with the front end of the crash box. The bumper crossbeam 104 is installed across the width of the vehicle on the crash boxes 102.
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[005] Fig. 2 illustrates the structure of crash box as known in the art. The crash box has two absorber members, i.e., upper member 204 and lower member 206. Both the upper member 204 and the lower member 206 joined with each other. The upper member 204 and the lower member 206 have bent flanges 208 at rear side. The flanges 208 of the upper member and the lower member 206 are welded 5 on front cross member plate 202. Further, the front cross member plate 202 along with absorber members is joined with front cross member of the vehicle. This structure of the crash box has high rigidity which does not absorb energy during collision. Further, these crash boxes may absorb or transmit impact energy of the vehicle collision occur during slow or high speed based on their designated design 10 structure. These crash boxes protect the vehicle body and occupants of the vehicle. These crash boxes are in-efficient to protect the pedestrian during collision of vehicle with the pedestrian.
[006] Fig. 3 illustrates another structure of the crash box as known in the art. This crash box is in octagonal in shape having two longitudinal members which 15 joined together to form a tubular structure. Further, a plurality of reinforcements is provided on the octagonal tubular structure to provide stiffness to the crash box. Similarly these types of crash boxes are useful for protecting the vehicle and occupants of the vehicle during collision of the vehicle. These crash boxes prove inefficient in pedestrian safety during pedestrian and vehicle collision. 20
[007] By the provision of energy structures in the vehicle, less of the impact force generated in the accident/collision is transmitted to the vehicle's occupants, thereby helping to avoid serious injury. But these structures are helpful to protect the vehicle’s occupants and vehicle body only.
[008] Therefore there is a need for a crash box or impact energy absorber 25 structure which could help to reduce risk of serious injury to pedestrians involved in road accidents with vehicles. The Pedestrian-friendly energy-absorbing structures need to be located on the external periphery of vehicles; a location where styling and certain other practical considerations are dominant factors in vehicle design. In addition, the energy absorbing structures must have an ability to 30
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withstand routine “wear and tear”, and an ability to yield when impact energy exceeds a threshold level. However, these requirements present a problem in that making a structure which is able to withstand light impact (e.g. from stone chipping projectiles or even car wash brushes) suggests design criteria which are the antithesis of those required to make a structure with desired “yield ability” to 5 safeguard pedestrians.
[009] It is desirable to provide a motor vehicle, and particularly the structure of the front end of the vehicle, to reduce the likelihood and/or severity of injuries suffered by a pedestrian that may be struck by the vehicle. It is a technical problem to design a front end structure that is able to yield or collapse in order to 10 absorb kinetic energy while still obtaining adequate fit/finish and proper dimensional stability.
[0010] The Front End Structure of the vehicle is designed to meet certain regulations like a) Pedestrian protection, b) Slow Speed Impact Test, c) Durability to meet the End of life of Vehicle without any failures in its Life Cycle in Normal 15 Running Conditions as specified by the manufacturer.
[0011] For meeting such criteria the Front End composing of Bumper, Bumper Beam, Crash Box should be designed in such a manner so that functioning they meet all of the above. Therefore, there is a need in the art to provide a structure for crash box that can satisfy all three regulations and effective in pedestrian safety 20 during collision of the vehicle with pedestrian.
OBJECTS OF THE INVENTION:
[0012] The principal objective of the present invention is to provide an energy absorber which absorbs impact energy and reduces injuries to pedestrian.
[0013] Another object of the present subject matter is to provide a crash box 25 structure for absorbing impact energy during vehicle collision with pedestrian.
[0014] Another object of the present subject matter is to provide a crash box structure with variable thickness to absorb impact energy.
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[0015] Another object of the present subject matter is to provide a crash box structure which fulfils pedestrian protection test, slow speed impact test, and durability test for the life cycle of the vehicle in normal conditions.
[0016] Yet another object of the present invention is to provide a crash box structure which is efficient in absorbing impact energy during the pedestrian 5 collision.
SUMMARY OF THE INVENTION:
[0017] The subject matter disclosed herein relates to a structure of crash box for absorbing impact energy during collision of vehicle with pedestrian. The crash box is made up from four absorber members. The crash box has front upper 10 absorber member, front lower absorber member, rear upper absorber member, and rear lower absorber member. All the four absorber members joined with each other to form a rectangular hollow tubular structure which has rectangular section. Each of the four absorber members overlappingly coupled to the other absorber member. The front upper absorber member overlappingly welded with the front 15 lower absorber member and rear lower absorber member at lower side and with the rear upper absorber member at upper side. The front lower absorber member overlappingly welded with the front upper absorber member and the rear lower absorber member. The front upper absorber member and the front lower absorber member joined with the rear upper and lower absorber member to form a 20 rectangular hollow tubular structure. Each of the absorber members is fixed integrally with other absorber member by welding means, such as spot welding, arc welding, and laser welding. Each of the absorber members is in U shape. The front upper and lower absorber member has different thickness as compared to the rear upper and lower absorber member. The front upper and lower absorber 25 member has low thickness as compared to the rear upper and lower absorber member. Further, each of the absorber members has variable length from each other. The length and thickness of the absorber members can be optimized based on the dimensions of the vehicle and front end of the vehicle. The front upper and lower absorber member a plurality of beads in transverse direction to provide 30
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deforming profile. The rear upper and lower absorber member has plurality of beads in direction of impact or in longitudinal direction or in axial direction to provide more stiffness to the rear absorber members as compared to front absorber members.
[0018] The rear upper and lower absorber member has plurality of bent flanges 5 on the rear side which front absorber members do not have. The bent flanges extend vertically outward direction from the rear side where the front upper and lower absorber members are not connected. The bent flanges of the rear upper and lower absorber member joined with front cross member plate by welding means, such as spot welding, arc welding, and laser welding. After the crash box is joined 10 with the front cross member plate, the front cross member plate is joined with the front cross member of the vehicle. When impact force is applied on the crash box during pedestrian collision with vehicle from front side of the vehicle, the crash box receives impact force in axial direction; the front bumper transfers the impact force on the bumper cross beam and then bumper cross beam transfers on the 15 crash box. Upon receiving the transferred impact force the front upper and lower absorber member plastically deforms to absorb the impact force and reduces injuries that might be caused to the pedestrian. When the impact force is high, for example, the vehicle collides with a hard structure at slow speed, the impact force is transferred to the crash box from the front bumper. The front upper and lower 20 absorber member of the rectangular hollow tubular crash box plastically deforms to absorb some amount of impact force and then transferred the un-absorbed extra impact force to the rear upper and lower absorber member of the crash box. The rear upper and lower absorber members have higher stiffness as compared to the front upper and lower absorber members, they receive the impact force and 25 deform plastically to absorb the impact force and protect the occupants of the vehicle and vehicle front body structure.
[0019] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with
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reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be 5 considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and 10 components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0021] Fig. 1 illustrates crash box and placement of the crash box under the bumper cross beam across width of the vehicle as known in the art; 15
[0022] Fig. 2 illustrates structure of the crash box as known in the art;
[0023] Fig. 3 illustrates octagonal structure of another crash box as known in the art;
[0024] Fig. 4 illustrate cross section of the octagonal cross section of the crash box as known in the art; 20
[0025] Fig. 5 illustrates placement of the crash box on left and right side of the bumper cross beam across the width of the vehicle, in accordance with an embodiment of the present subject matter;
[0026] Fig. 6 illustrates structure of crash box mounted on front cross member plate, in accordance with an embodiment of the present subject matter; 25
[0027] Fig. 7 illustrates structure of the crash box in rectangular shape, in accordance with an embodiment of the present subject matter;
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[0028] Fig. 8 illustrates exploded view of the crash box, in accordance with an embodiment of the present subject matter; and
[0029] Fig. 9 illustrates cross section of the crash box, in accordance with an embodiment of the present subject matter.
[0030] The figures depict embodiments of the present subject matter for the 5 purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS: 10
[0031] The subject matter disclosed herein relates to a structure of crash box for absorbing impact energy during collision of vehicle with pedestrian. The crash box is made up of four absorber members. The crash box has front upper absorber member, front lower absorber member, rear upper absorber member, and rear lower absorber member. All the four absorber members joined with each other to 15 form a rectangular hollow tubular structure which has rectangular section. Each of the four absorber members overlappingly coupled to the other absorber member. The front upper absorber member overlappingly welded with the front lower absorber member and rear lower absorber member at lower side and with the rear upper absorber member at upper side. The front lower absorber member 20 overlappingly welded with the front upper absorber member and the rear lower absorber member. The front upper absorber member and the front lower absorber member joined with the rear upper and lower absorber member to form a rectangular hollow tubular structure. Each of the absorber members is fixed integrally with other absorber member by joining means, such as spot welding, arc 25 welding, laser welding, and screw mounting. Each of the absorber members is in U shape. The front upper and lower absorber member has different thickness as compared to the rear upper and lower absorber member. The front upper and lower absorber member has low thickness as compared to the rear upper and lower absorber member. Further, each of the absorber member has variable length 30
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from each other. The length and thickness of the absorber members can be optimized based on the dimensions of the vehicle and front end of the vehicle. The front upper and lower absorber members have a plurality of beads in transverse direction to provide a deforming profile. The rear upper and lower absorber members have plurality of beads in direction of impact or in longitudinal direction 5 or in axial direction to provide more stiffness to the rear absorber members as compared to the front absorber members.
[0032] The rear upper and the lower absorber members have plurality of bent flanges on the rear side which front absorber members do not have. The bent flanges extend vertically outward direction from the rear side where the front 10 upper and lower absorber members are not connected. The bent flanges of the rear upper and lower absorber members are joined with front cross member plate by joining means, such as spot welding, arc welding, laser welding inert gas welding, and screw mounting. After the crash box is joined with the front cross member plate, the front cross member plate is joined with the front cross member of the 15 vehicle. When impact force is applied on the crash box during pedestrian collision with vehicle from front side of the vehicle, the crash box receives impact force in axial direction; the front bumper transfers the impact force on the bumper cross beam and then bumper cross beam transfers on the crash box. Upon receiving the transferred impact force the front upper and lower absorber members plastically 20 deform to absorb the impact force and reduces injuries caused to the pedestrian. When the impact force is high, for example, the vehicle collides with a hard structure at slow speed, the impact force is transferred to the crash box from the front bumper. The front upper and lower absorber members of the rectangular hollow tubular crash box plastically deform to absorb some amount of impact 25 force and then transfer the un-absorbed extra impact force to the rear upper and lower absorber member of the crash box. The rear upper and lower absorber members have higher stiffness as compared to the front upper and lower absorber members, receive the impact force and deform plastically to absorb the impact force and protect the occupants of the vehicle and vehicle front body structure or 30 transmit the force to the rear members to which they are joined.
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[0033] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those 5 skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the 10 concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the 15 following description when considered in connection with the accompanying figures.
[0034] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject 20 matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0035] Fig. 5 illustrates mounting of crash box at front end of the vehicle, in accordance with the present subject matter. The crash box is disposed in between 25 front cross member plate and bumper cross beam 500a of the vehicle. On the bumper cross beam 500a, front bumper of the vehicle is mounted. When impact force is applied on the front bumper of the vehicle during the collision, the front bumper transfers the impact force on the bumper cross beam and then bumper cross beam transfers the impact force on the crash box. Further, the crash box is 30
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placed at both sides, such as left and right side of the vehicle across the width of the vehicle at front and rear end. In the present subject matter, crash box is explained with reference to its position at the front end of the vehicle. It should be noted that crash box is not limited to the front end of the vehicle; the crash box can be placed at the rear side of the vehicle also. 5
[0036] Fig. 6 illustrates mounting of crash box on front cross member plate, in accordance with the present subject matter. The crash box 600 is mounted on front end of front cross member plate 502. After mounting the crash box 600 on the front cross member plate 502, the front cross member plate 502 and crashbox 600 together is mounted on the front cross member of the vehicle which is hard cross 10 member. The front cross member plate 502 and the crashbox 600 together can be mounted on the front cross member by attachment means, such as nut-bolt, welding, spot welding. The crashbox 600 is n-sided hollow tubular structure. The n-sided crashbox 600 can be in rectangular, pentagon shape, hexagon, and octagon shape. Further, shape of the n-sided hollow tubular structure of the crash 15 box 600 depends on shape and dimension of the vehicle and impact absorbing requirements of the vehicle. For the simplicity, the present invention is explained with the rectangular structure of the crash box 600. It should be noted that all shape and configurations of the crash box with the present subject matter falls under the scope of the present invention. The front cross member plate 502 is 20 made of high stiffness and material having higher thickness.
[0037] Fig. 7 illustrates the structure of the crash box, in accordance with the present subject matter. The present crash box 600 has front upper absorber member 602, front lower absorber member 604, rear upper absorber member 606, and rear lower absorber member 608. The front upper absorber member 602, the 25 front lower absorber member 604, the rear upper absorber member 606, and the rear lower absorber member 608 overlappingly joined with each other to form a rectangular hollow tubular body structure which has rectangular section. The crash box 600 may have n-sided hollow tubular structure for absorbing the impact energy. Similarly, in the n-sided tubular structure have four types of absorbers 30
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with different shapes according to the requirement and connected with each other to form the n-sided hollow tubular body structure of crash box. For example, four types of absorbers joined with each other to form a pentagon type crash box. The present description explains the crash box in rectangular shape to explain the subject matter clearly. Further, any shape of crash box with present inventive step 5 should fall under the scope of present invention. Each of the four absorber members 602, 604, 606, 608 overlappingly coupled to the other absorber member to form a rectangular hollow tubular structure 600. The front upper absorber member 602 overlappingly coupled with the front lower absorber member 604 and rear lower absorber member 608 at lower side and with the rear upper 10 absorber member 606 at upper side. The front lower absorber member 604 overlappingly coupled with the front upper absorber member 602 and the rear lower absorber member 608. Similarly, the rear lower absorber member 608 and the rear upper absorber member 606 overlappingly coupled with the front upper absorber member 602 and the front lower absorber member 604 to form a 15 rectangular hollow tubular structure 600.
[0038] Accordingly, the front upper absorber member 602 and the front lower absorber member 604 joined with the rear upper absorber member 606 and the rear lower absorber member 608 to form a rectangular hollow tubular body structure 600. Further, the complete rectangular hollow tubular structure of crash 20 box 600 can be divided into two rectangular hollow tubular structures. First structure is front rectangular hollow tubular structure made from the front upper and lower absorber member 602, 604 and second structure is rear rectangular hollow tubular structure made from the rear upper and lower absorber member 606, 608. The rear rectangular hollow tubular structure has high stiffness as 25 compared to the front rectangular hollow tubular structure. Each of the absorber members is fixed integrally overlap with other absorber member by joining means, such as spot welding, arc welding, laser welding, and screw mounting. The overlap portions of the absorber member are joined by joining means, such as spot welding, arc welding, laser welding, and screw mounting. Further, shape of 30 each of the absorber members is U shape. The shape of each absorber member
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may be of any type to form n-side hollow tubular strucutre The front upper absorber member 602 and the front lower absorber member 604 have different thickness as compared to the rear upper absorber member 606 and the rear lower absorber member 608. The front upper absorber member 602 and the front lower absorber member 604 have low thickness as compared to the rear upper absorber 5 member 606 and the rear lower absorber member 608. Due to the variable thickness, the rear upper absorber member 606 and the rear lower absorber member 608 have high stiffness as compared to the front upper and lower absorber member 602, 604.
[0039] Each of the absorber members has different length from each other. The 10 front upper absorber member 602 and the front lower absorber member 604 have a plurality of beads 612, 613, 614 in transverse direction. Further, the rear upper absorber member 606 and the rear lower absorber member 608 have a plurality of beads 615, 616, 617 in direction of impact or in longitudinal direction or in axial direction to provide more stiffness to the rear absorber members 606, 608 as 15 compared to front absorber member 602, 604. The length and thickness of the absorber members 602, 604, 606, 608 can be optimized based on the dimensions of the vehicle and front end of the vehicle.
[0040] The rear upper absorber member 606 and the rear lower absorber member 608 have bent flanges 610, 611, 613(611,613 not marked in fig. any particular 20 reason) on free end side or rear side which do not have front absorber members 602, 604. The bent flanges 610, 611, 613 extend vertically outward direction from the rear side where the front upper and lower absorber members are not connected. The bent flanges 610, 611, 613 of the rear upper absorber member 606 and the rear lower absorber member 608 joined with the front cross member plate 25 502 by welding means, such as spot welding, arc welding, and laser welding. After the crash box 600 is mounted on the front cross member plate 502, the front cross member plate 502 is mounted on the front cross member of the vehicle. When impact force is applied on the crash box 600 during pedestrian collision with vehicle from front side of the vehicle, the crash box 600 receives impact 30
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force in axial direction. The front bumper transfers the impact force on the crash bumper cross beam and then the bumper cross beam transfers the impact force on the crash box 600. Upon receiving the transferred impact force the front rectangular hollow tubular structure plastically deforms to absorb the impact force and reduces injuries cause to the pedestrian due to collision. When the impact 5 force is high, for example, the vehicle collides with a hard structure at slow speed; the impact force is transferred to the crash box 600 from the front bumper of the vehicle. The front rectangular hollow tubular structure of the crash box 600 plastically deforms to absorb the impact force and then transfers the unabsorbed impact force or extra impact force to the rear rectangular hollow tubular structure 10 of the crash box 600. The rear rectangular hollow tubular structure deforms plastically to absorb the unabsorbed extra impact force and protect the occupants of the vehicle and vehicle front body structure from the injuries and damages, respectively.
[0041] Fig. 8 illustrates exploded view of the crash box, in accordance with the 15 present subject matter. As explained in the figure 7, each of the absorber members has U shape. Each of the four absorber members 602, 604, 606, 608 overlappingly coupled to the other absorber member to form a rectangular hollow tubular structure 600. A welding means is provided on the overlapped portion to join the four absorber members. Further, the rear absorber members 606, 608 have bent 20 flanges which are welded on the front cross member plate 502. Further, each of the four absorber members has perforations that aid in assembly and manufacturing of the hollow tubular structure. The front upper absorber member 602 and the front lower absorber member joins with each other to form a front rectangular hollow tubular structure which is effective in energy absorbing 25 capability in case of pedestrian crash. Further, the front rectangular hollow tubular structure has stiffness in required amount so that the front rectangular hollow tubular structure fulfils the slow speed impact test. The front rectangular hollow tubular structure has rigidity to sustain loads of the parts which are welded on it in normal loading conditions of the vehicle. The rear rectangular hollow structure of 30 the crash box which is made from the rear upper absorber member 606 and the
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rear lower absorber member 608 has high stiffness for joining the parts with the front cross member plate through welding. Further, the high stiffness of the rear rectangular hollow structure provides rigidity to the crash box for sustaining the loads in required normal conditions of the vehicle. The dimensions as well as the choice of materials can be optimized in such a way so that the crash box can be 5 manufacture as per the requirement of the vehicle.
[0042] Fig. 9 illustrates the cross section B-B of the crash box 600, in accordance with the present subject matter. Length 602a of the front upper absorber member 602 is different from the length 604a of the front lower absorber member 604. Similarly, length 606a of the rear upper absorber member 606 is different from the 10 length 608a of the rear lower absorber member 608. Further the length and thickness of the absorber members can be optimized as per the requirements of the vehicle.
[0043] The crash box 600 is efficient in avoid injuries to pedestrian as well as occupants of the vehicle. Further, the crash box 600 met all three requirements, 15 i.e., 1) Energy absorbing so that the requirements related to passenger and pedestrian safety are met, 2) Rigidity so that no failures are present under loading conditions specified by manufacturer, 3) Energy resisting so that slow speed resisting requirements as per requirements are met which is necessary for a crash box. 20
[0044] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component 25 of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
1. A crash box structure (600) for absorbing impact energy of during vehicle collision, the crash box structure (600) comprising:
a front upper absorber member (602);
a front lower absorber member (604); 5
a rear upper absorber member (606); and
a rear lower absorber member (608), wherein the front upper absorber member (602), the front lower absorber member (604), the rear upper absorber member (606), and the rear lower absorber member (608) overlappingly joined with each other to form a n-sided hollow tubular 10 structure with n-sided section.
2. The crash box structure (600) as claimed in claim 1, wherein the n-sided hollow tubular structure is selected from rectangular structure, pentagon structure, hexagon structure, octagon structure. 15
3. The crash box structure (600) as claimed in claim 1, wherein selection of type of the n-sided hollow tubular structure depends on vehicle requirement.
4. The crash box structure (600) as claimed in claim 1, wherein the front upper 20 absorber member (602) over lappingly coupled with the front lower absorber member (604) and the rear lower absorber member (608) at lower side and with the rear upper absorber member (606) at upper side,
wherein the front lower absorber member (604) overlappingly coupled with the front upper absorber member (602) and the rear lower absorber 25 member (608),
wherein the rear lower absorber member (608) and the rear upper absorber member (606) overlappingly coupled with the front upper absorber member (602) and the front lower absorber member (604) to form a rectangular hollow tubular structure. 30
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5. The crash box structure (600) as claimed in claim 1, wherein the front upper absorber member (602) and the front lower absorber member (604) joined with each other and forms a n-sided front hollow tubular structure, wherein the rear upper absorber member (606) and the rear lower absorber member (608) joined with each other to form a rear rectangular hollow tubular 5 structure.
6. The crash box structure (600) as claimed in claim 1, wherein the rear upper absorber member (606) and the rear lower absorber member (608) has a plurality of bent flanges (610, 611, 612, 613) which are welded with front 10 cross member plate (502).
7. The crash box structure (600) as claimed in claim 1, wherein shape of the front upper absorber member (602), the front lower absorber member (604), the rear upper absorber member (606), and the rear lower absorber member 15 (608) is in U shape.
8. The crash box structure (600) as claimed in claim 1, wherein length and thickness of each of the front upper absorber member (602), the front lower absorber member (604), the rear upper absorber member (606), and the rear 20 lower absorber member (608) are different from each other.
9. The crash box structure (600) as claimed in claim 5, wherein thickness and stiffness of the rear rectangular hollow tubular structure is more than the 25 front rectangular hollow tubular structure.
10. The crash box structure (600) as claimed in claim 1, wherein the joining method is selected from spot welding, arc welding, laser welding, Inert Gas welding, and screw mounting. 30
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11. The crash box structure (600) as claimed in claim 1, wherein the front upper absorber member (602) and the front lower absorber member (604) has plurality of beads (614, 618,619) in transverse direction, wherein the rear upper absorber member (604) and the rear lower absorber member (608) has plurality of beads (615, 616, 617) in longitudinal direction. 5
12. The crash box structure (600) as claimed in claim 1, wherein the rectangular hollow tubular structure plastically deforms upon absorbing the impact force during the vehicle collision.