FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a front impact energy absorber for vehicle, and, in particular, to a front lower leg impact energy absorber for protection of pedestrian leg during frontal vehicle collision. The present front lower energy absorber to absorb the impact energy and protects leg of pedestrian and reduces injury to pedestrian upon impact. More particularly, the present subject matter relates to the front lower energy absorber which has groove and bead structure at impact prone zones to absorbs the pedestrian impact energy and reduce injury to pedestrian leg.
BACKGROUND AND PRIOR ART:
[002] Current bumper systems are formed of plastic material to absorb impact energy during crash. Further, the bumper system has an energy absorber which absorbs energy during pedestrian impact with the vehicle. There are several zones, such as upper leg and lower leg where vehicle hit the pedestrian. The upper leg energy absorber is provided at the upper side of the bumper and mounted on the upper cross member of the vehicle. Further, the lower leg energy absorber is provided at lower side and mounted on lower cross member of the vehicle.
[003] During the collision, the pedestrian leg is impacted with the vehicle front end which causes local area bending of pedestrian lower leg. This impact causes severe injuries to knee and Tibia portion of leg.
[004] To make the vehicle pedestrian safe, pedestrian safety requirements have to be followed. If any vehicle does not fulfill the pedestrian safety requirements, it would be dangerous for pedestrian. There are two types of pedestrian leg impactors, i.e., TRL test and Flex PLI test which can be used to evaluate the safety of pedestrian. With pedestrian safety requirements, front section of the vehicle can be qualitatively assessed according to the following criteria: 1) impact with an upper leg, 2) impact with a lower leg, 3) impact with the head on a bonnet of a motor vehicle.
[005] In order to achieve the pedestrian safety requirements, different embodiments of bumper assemblies were proposed by the automobile industry for a front region of a passenger car faced with a casing. Several energy absorbers can be seen in the patent publications in JP2012254696A, CN102951205A, and CN101641240B. All the energy absorber disclosed in the cited patent publications has complex shape and work along with the upper absorber. Further, the all absorber are heavy in weight and costly.
[006] There are two regions, i.e., upper region and lower region in the vehicle front bumper which come into contact with the leg of the pedestrian during collision. The upper region consists of Femur portion of the leg and lower region consists of Knee and Tibia portion of the leg. Generally, the bumper includes bumper fascia which is provided to ensure a pleasant aesthetic external appearance and guarantee desired aerodynamics. The lower region has reinforcing element which is frequently also referred as lower cross member to as a so-called “lower bumper stiffener” (LBS for short) for “pedestrian-protection lower leg impact”, or can be designated as a reinforcement of the lower front bumper region for the protection of pedestrians in a leg impact. These reinforcing elements are made of foam or other highly cost materials which absorb the impact energy.
[007] Fig. 1 illustrates the placement of the energy absorbers in front side bumper of the vehicle for absorbing the impact energy as known in the art. As shown in the fig. 1, the front bumper assembly 100 has upper cross member 101 and lower cross member 102 to mount upper energy absorber 101a and lower energy absorber 102a, respectively. The upper energy absorber 101a and the lower energy absorber 102a absorbs the impact energy of the vehicle during collision with the pedestrian. The upper absorber 101a protects the upper portion of the leg, whereas the lower absorber 102a protects the lower portion of the leg. Once the energy absorbers 101a, 102a are mounted on the upper and lower cross member, a bumper fascia 103 is mounted on the upper and the lower cross member of the vehicle at front side. The disadvantage associated with these energy absorbers is that they are foam based absorbers which results in increase in cost.
[008] All existing front lower energy absorbers are foam based energy absorbers which increase the cost and includes complex manufacturing processes. The Chinese patent CN101641240B defines a sheet metal based energy absorber. The technical problem associated with energy absorber of the present Chinese patent is that it does not absorb the impact energy efficiently. Further, optimization of the stiffness of the absorber is not present along the front surface of the vehicle. It has uniform stiffness through the absorber.
[009] Therefore, there is a need in the art to provide a front lower energy absorber which has optimized shape and configuration for absorbing the impact energy efficiently upon impact at different point of the front lower energy absorber. Further, it is also required that the front lower energy absorber should be simple and cost effective, and which can be easily mounted onto the lower cross member.
OBJECTS OF THE INVENTION:
[0010] The principal objective of the present invention is to provide a front lower energy absorber which prevents the bending of pedestrian leg by absorbing impact energy in the event of pedestrian collision with vehicle front end.
[0011] Another object of the present subject matter is to provide a front lower energy absorber to absorb lower leg impact energy during collision of vehicle with pedestrian from front side.
[0012] Another object of the present subject matter is to provide an optimized front lower energy absorber which has groove and bead structure to provide required stiffness to the front lower energy absorber at different point.
[0013] Yet another object of the present invention is to provide a front lower energy absorber which is simple and inexpensive, and efficiently absorbs the impact energy without major injury to lower leg of the pedestrian.

SUMMARY OF THE INVENTION:
[0014] The subject matter disclosed herein relates to a front lower energy absorber which is positioned in between the front bumper and lower cross member of the vehicle. The energy absorber is made of single sheet metal which is formed by a die tool. The front lower energy absorber is configured and dimensioned to be mounted at inner side of the front bumper along width of the vehicle to absorb impact energy of frontal impact. The front lower energy absorber has upper part, middle part, and lower part. The upper part and the lower part are connected with the middle part to form a hat type cross section. The upper part and the lower part have inline groove and bead structure in lateral direction along width of the vehicle. The groove and the bead structure allow collapse of the front lower energy absorber to absorb impact energy during pedestrian impact. The front lower energy absorber is a hollow structure in middle in shape of hat. Further, the front lower energy absorber has one longitudinal bead at both the corners to provide stiffness in direction of pedestrian impact and prevent hitting of pedestrian leg to the lower cross member which is a hard part. The front lower energy absorber has convex shape where corner are narrow and central part is wider to absorb more impact energy as compared to corners. The front lower energy absorber has upper flange and lower flange at upper part and lower part, respectively which project perpendicularly away from the upper part and the lower part. The flanges extend along width of the front lower energy absorber in lateral direction at rear end towards lower front cross member for mounting. The groove and bead structure guides plastic deformation or collapse of the front lower energy absorber to absorb the impact energy during pedestrian impact. Due to the optimization of the groove and bead structures in the front lower energy absorber, the front lower energy absorber plastically deforms to absorb the impact energy efficiently.
[0015] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with 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
[0016] 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 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 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:
[0017] Fig. 1 illustrates known energy absorber for lower leg and upper leg in the front bumper of the vehicle;
[0018] Fig. 2a illustrates structure of present front lower energy absorber, in accordance with an embodiment of the present subject matter;
[0019] Fig. 2b illustrates another view of the present front lower energy absorber, in accordance with an embodiment of the present subject matter;
[0020] Fig. 3a, 3b, and 3c illustrate location of front lower absorber in the vehicle, in accordance with an embodiment of the present subject matter;
[0021] Fig. 4a, 4b, and 4c illustrate cross sectional view of the front lower absorber in the vehicle, in accordance with an embodiment of the present subject matter;
[0022] Fig. 5a and 5b illustrate evaluation of front lower absorber with the leg impact, in accordance with an embodiment of the present subject matter;
[0023] Fig. 6 illustrates MCL elongation and tibia bending moment in the present front lower absorber, in accordance with an embodiment of the present subject matter; and
[0024] Fig. 7 illustrates energy absorbing capabilities of the present front lower absorber, in accordance with an embodiment of the present subject matter.
[0025] The figures depict embodiments of the present subject matter for the 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:
[0026] The subject matter disclosed herein relates to a front lower energy absorber which is positioned in between the front bumper and lower cross member of the vehicle. The energy absorber is made of single sheet metal which is formed by a die tool. The front lower energy absorber is configured and dimensioned to be mounted at inner side of the front bumper along width of the vehicle to absorb impact energy of frontal impact. The front lower energy absorber has upper part, middle part, and lower part. The upper part and the lower part are connected with the middle part to form a hat type cross section. The upper part and the lower part have inline groove and bead structure in lateral direction along width of the vehicle. The groove and the bead structure allow collapse of the front lower energy absorber to absorb impact energy during pedestrian impact. The front lower energy absorber is a hollow structure in middle in shape of hat. Further, the front lower energy absorber has one longitudinal beam at both the corners to provide stiffness in direction of frontal crash and prevent hitting of the lower cross member which is a hard part. The front lower energy absorber has convex shape where corner are narrow and central part is thicker to absorb more impact energy as compared to corners. The front lower energy absorber has upper flange and lower flange at upper part and lower part, respectively which project perpendicularly away from the upper part and the lower part. The flanges extend along width of the front lower energy absorber in lateral direction at rear end towards lower front cross member for mounting. The groove and bead structure guides plastic deformation or collapse of the front lower energy absorber to absorb the impact energy during frontal crash. Due to the optimization of the groove and bead structures in the front lower energy absorber, the front lower energy absorber plastically deforms to absorb the impact energy efficiently.
[0027] 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 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 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 following description when considered in connection with the accompanying figures.
[0028] 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 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.
[0029] The present subject matter provides a front lower energy absorber, which is capable of reducing the severity of pedestrian lower limb injury in case of Flex PLI in two approaches: (a) by reducing leg impactor intrusion into the vehicle’s front end (acting as a stiffener) (b) by providing soft cushioning support to the pedestrian impact with vehicle in longitudinal direction (acting as an absorber).
[0030] Fig. 2a illustrates structure of the present front lower absorber for absorbing the pedestrian leg impact force, in accordance with the present subject matter. The present front lower energy absorber 200 has top surface 201, front face 202, and bottom surface 203. The upper part 201 and the lower part 203 are connected to the middle part 202 to its two sides along lateral direction (along width). Further, the upper part 201 has upper flange 201a which extend perpendicularly away from the upper part 201 and extend along width X in lateral direction at rear end 205 towards lower front cross member for assembly purpose. Similarly, the lower part 203 has lower flange 203a which extend perpendicularly away from the lower part 203 and extend along width X in lateral direction at rear end 205 towards lower front cross member for mounting purpose. The front lower energy absorber 200 can be assembled to vehicle by welding, fasteners or with the help of adhesive. Connection of the upper part 201, lower part 203, the middle part 202 and extended flanges 201a, 203a forms a hat shaped cross section. The upper part 201, the middle part 202, and the lower part 203 defines a hollow structure with height equals to height of the middle part 202.
[0031] The upper part 201 has a groove 206 in lateral direction along width at front end 204 of the vehicle which is towards inner surface of the front bumper. Further, the upper part 201 has a bead structure 207 in lateral direction along with at rear end 205 towards lower front lower cross member. Similarly, the lower part 203 has a groove 206a (not shown in the figure) in lateral direction along width at front end 204 of the vehicle which is towards inner surface of the front bumper. Further, the lower part 203 has a bead structure 207a in lateral direction along with at rear end 205 towards lower front lower cross member. The groove 206 and the bead structure 207 of the upper part 201 are inline with the groove 206a and the bead structure 207a of the lower part 203. The groove 206, 206a and the bead structure 207, 207a allow collapse or plastic deformation of the front lower energy absorber 200 during frontal crash.
[0032] Further, the front lower energy absorber 200 has one longitudinal bead 208 at left end corner 209a and one longitudinal bead 208 at right end corner 209b. The longitudinal beads 208 are provided at the corner to prevent leg striking gusset member or stiff member, such as lower cross member directly. The longitudinal beads 208 increase the stiffness at the corner of the lower cross member to avoid high local bending of tibia portion of pedestrian lower leg. While at other locations in the front lower energy absorber 200, have lateral beads 207 and the lateral groove 206 to allow plastic deformation of the front lower energy absorber to absorb impact energy during pedestrian impact. The length and depth of the beads and groove profile can be optimized based on stiffness requirement and space availability between front bumper and vehicle front-end, i.e., lower cross member which is a Body-part.
[0033] Referring to figure 2b, the front lower energy absorber 200 has two longitudinal beads 208 one at left end corner 209a and other at right end corner 09b) to provide stiffness at corners and to prevent direct hitting of legform with the lower cross member. The front lower energy absorber 200 is in a convex shape with wider part at center and narrow part at the corners.. In longitudinal direction, the central part has width B which is more than the width A at corners. The width of the lower absorber depends upon the front bumper design and vehicle layout. Further, the groove 206 and the bead structure 207 mostly covered the central part based on the energy absorption capability requirement. The width of the absorber 200 decreases gradually from the center to the corner.
[0034] As shown in the figure 3a, 3b, and 3c, the front lower energy absorber 200 is configured and dimensioned to be mounted at inner side of the front bumper along width of the vehicle to absorb impact energy of pedestrian impact. Further, width of the front lower energy absorber 200 can be optimized as per layouting of the vehicle front-end.
[0035] Referring to figure 4a, 4b, 4c, the front lower energy absorber 200 has bead structure 207 and 207a near the upper flange 201a and the lower flange 203a. The middle part 202 receives the impact energy from front end and collapse or plastically deform towards inner side due to profile of the groove 206 and the bead structure 207. The front lower energy absorber 200 limits inward (TL) intrusion of lower leg towards the vehicle which helps to reduce overall leg bending about knee-joint hence reducing the leg injury values. Further, the front lower energy absorber is made of sheet metal. The thickness of the front lower energy absorber varies according to the shape and size of the absorber which depends on the dimensions of the vehicle. The thickness of the sheet metal is 0.48mm to 0.65mm, preferably 0.50mm to 0.58mm. However, the thickness and material can be varied based on the performance requirement.
[0036] Fig. 5a and 5b illustrate evaluation of front lower absorber with the leg impact, in accordance with an embodiment of the present subject matter. Fig. 5a and 5b illustrates test result with the present front lower energy absorber with the leg impactor, where the leg impactor can be any existing leg impactor. The front lower energy absorber 200 protects the leg at tibia 3 from bending. As shown in the figure 5b, the front lower energy absorber 200 reduces the inward intrusion of the impactor lower by x distance also rebounds the lower tibia portion of pedestrian leg away from the vehicle. This results in reducing overall impactor bending about knee-joint and hence Medical Collateral Ligament (MCL) elongation is reduced.
[0037] Fig. 6 illustrates MCL elongation and tibia bending moment in the present front lower absorber, in accordance with an embodiment of the present subject matter. The front lower energy absorber 200 limits inwardintrusion of impactor lower which helps to reduce overall impactor bending about knee-joint thereby helped to reduce the leg injuries (MCL elongation and Tibia bending moment). With the addition of the present front lower energy absorber, the MCL elongation value is reduced by 31.5%, tibia bending moment is reduced by 31.5% as shown in the figure 6.
[0038] Fig. 7 illustrates energy absorbing capabilities of the present front lower absorber, in accordance with an embodiment of the present subject matter. As shown in the figure 7, the energy absorbed by the front lower energy absorber 200 undergoes plastic deformation and absorbs 18.5% of impact energy. This helps to prevent hitting of pedestrian leg with stiff member of vehicle and eventually helped to reduce the leg injury values.
[0039] The present front lower energy absorber can be manufactured by simple forming process, such as stamping, bending and/or punching operations which helps in significant saving in manufacturing and tooling costs. The present front lower energy absorber can be easily assembled to vehicle using welding, bolt fastening or using adhesives. Material, Thickness, and dimensions of the Front Lower Energy absorber can be optimized based on vehicle layout and performance requirements. Further, the plurality of beads and grooves can be used to achieve optimum pedestrian leg performance. Furthermore, position of grooves and beads can be varied based on stiffness requirement.
[0040] 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 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 front lower energy absorber (200) for front bumper of vehicle to protect pedestrian leg during impact, the front lower energy absorber (200) comprising:
an upper part (201) with a groove (206) and a bead structure (207) in lateral direction;
a lower part (203) with a groove (206a) and a bead structure (207a) in lateral direction;
the upper part (201) and the lower part (203) are connected with a middle part (202) to form the front lower energy absorber (200),
wherein the groove (206) and the bead structure (207) on the upper part (201) are inline with the groove (206a) and the bead structure (207a) on the lower part (203) to allow collapse of the front lower energy absorber (200) to absorb impact energy in front end (204).
2. The front lower energy absorber (200) as claimed in claim 1, wherein the middle part (202) defines height of the front lower energy absorber (200).

3. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) has the groove (206, 206a) in lateral direction along width at front end (204) which is towards inner surface of front bumper.

4. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) has the bead structure (207, 207a) in lateral direction along width at rear end towards lower front member.

5. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) is configured and dimensioned to be mounted inner side of the front bumper along width of the vehicle to absorb impact energy of frontal impact.

6. The front lower energy absorber (200) as claimed in claim 1, wherein the upper part (201) has a flange (201a) which extend along width (X) in lateral direction at rear end (205) towards lower front member for mounting of the front lower energy absorber (200) on the lower front member of the vehicle.

7. The front lower energy absorber (200) as claimed in claim 1, wherein the lower part (203) has a flange (203a) which extend along width (X) in lateral direction at rear end (205) towards lower front member for mounting of the front lower energy absorber (200) on the lower front member of the vehicle.

8. The front lower energy absorber (200) as claimed in claim 1, wherein joining of the upper part (201), the middle part (202), and the lower part (203) defines a hollow structure with height equals to height of the middle part (202).

9. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) has one longitudinal bead (208) at left end corner (209a) and other at right end corner (209b) to provide stiffness at corners.

10. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) is wider at central part (B) as compared to corner part (209a, 209b), wherein the front lower energy absorber (200) defines a convex shape with wider central part, wherein width of the lower absorber (200) depends upon the front bumper design and vehicle layout and varies to meet performance requirement.

11. The front lower energy absorber (200) as claimed in claim 1, wherein the front lower energy absorber (200) is made of single sheet metal plate, wherein material and thickness of lower absorber (200) depends upon performance requirement.