Bumper system with face-mounted energy absorber

A bumper system includes a tubular beam having front and rear walls, and a plurality of horizontally-extending walls that interconnect the front and rear walls. An energy absorber has a rear surface with a recess shaped to mateably receive and support the beam, and includes end sections that extend to be coplanar with the rear wall of the beam. The end sections cover the front wall and also at least partially cover a top, bottom and ends of the beam, and are constructed to flex and absorb energy to reduce a likelihood of vehicle damage. In one form, the end sections include honeycomb sections that engage beam mounts to transfer impact energy directly to the mounts. In another form, the end sections include cantilevered flanges that extend outwardly from ends of the energy absorber for impact absorption at the vehicle corners.

BACKGROUND OF THE PRESENT INVENTION

The present invention relates to automotive bumper systems having beams and energy absorbers located on faces of the beams.

Many vehicle designs use energy absorbers positioned on a face or front surface of a steel bumper beam to improve energy absorption of a bumper system. The energy absorbers provide an initial level of energy absorption for low impact, including reducing damage during low impact, and also provide a supplemental level of energy absorption during high impact (i.e. before and at the time that the beam and vehicle begin to absorb substantial amounts of energy). Usually, the energy absorbers are fastened to the bumper beam with fasteners that assure accurate positioning of the energy absorber on the beam. The reasoning includes accurately positioning the energy absorber on the bumper beam to assure consistent performance, as well as to assure accurate positioning for aesthetics and assembly (e.g. to assure a good fit of the front-end fascia over the energy absorber and beam during assembly).

However, improvements are desired in terms of temporary and permanent attachment, and for improved and more reliable energy absorption. Typically, attachment of the energy absorber to bumper beams requires a plurality of mechanical fasteners. This is disadvantageous since mechanical fasteners require manual labor to install, which can add undesirably to cost. Also, the mechanical fasteners can result in localized and non-uniform stress distribution during impact, resulting in inconsistent collapse of the bumper system and poor energy absorption on impact. Further, fixing the energy absorber to the beams results in an inability of the energy absorber to shift and adjust to non-perpendicular and uneven loads transmitted from the impacting bodies. At the same time, depending on the bumper system, sometimes shifting of an energy absorber is not good since it can result in unpredictable, premature and non-uniform collapse, resulting in poor or inconsistent energy absorption by the bumper system.

Improvement is also desired for corner impact structure on bumper systems. Many existing bumper systems require that a front surface of an end of a bumper beam be shaped at an increased angle relative to the front of rest of the bumper beam to match an aerodynamic curvature of the vehicle at its front fender. One way to achieve this is by miter cutting an end of the bumper beam at an angle, and thereafter welding a plate onto the angled end to form a compound-angled flat front surface for supporting an energy absorber such as a foam cushion. Another way is to deform or crush an end of the bumper beam to form an angled front surface. Yet another way is to weld a bracket onto an end of the bumper beam, with the bracket extending longitudinally beyond the bumper beam to form the desired shape. However, all of these alternatives have drawbacks. For example, they each require a secondary operation, result in increased dimensional variation, and require significant investment in capital equipment. Further, they can lead to increased scrap, a substantial increase in manpower and manufacturing time, and substantial increase in inventories and work in process.

For all of the above reasons, there is a desire for bumper systems that yield a better, more consistent, more reliable, and greater impact energy absorption, both for low and high impact events, and also for square and skewed impact directions. Also, there is a desire for improvements facilitating assembly of an energy absorber to a beam, with lower cost and fewer parts, and with less labor. Still further, there is a desire for energy absorber designs that allows adjustment and tuning for optimal front end and corner impact strengths, even late in the bumper development program, and yet that do not require expensive or complex molding techniques or assembly techniques nor secondary miter cutting or crush forming bumper end sections. Still further, there is a desire for energy absorber designs that are adaptable for use with many different bumper beam cross-sectional shapes and sizes. Also, energy absorber designs are desired that are flexible and usable on non-linear bumper beams having different curvatures and longitudinal sweeps, and having different cross sections.

SUMMARY OF THE PRESENT INVENTION

In one aspect of the present invention, a bumper system for a passenger vehicle includes a tubular beam having a front wall, at least one rear wall, and a plurality of horizontally-extending walls that interconnect the front and rear walls, the beam being adapted for attachment to a vehicle frame. An energy absorber is provided having a rear surface with a recess shaped to mateably receive and support the beam. The energy absorber includes end sections that extend to a location approximately coplanar with the rear wall of the beam. The end sections of the energy absorber define corners of the vehicle and are configured to structurally support fascia of the vehicle at the corners. The end sections cover the front wall and also at least partially cover top, bottom and ends of the beam, with the end sections being constructed to flex and absorb energy to reduce a likelihood of vehicle damage.

In another aspect of the present invention, a bumper system for vehicles includes a tubular bumper beam including a front face and opposing ends, and further includes spaced-apart mounts supporting the beam and adapted for attachment to a vehicle frame. An energy absorber includes a main section engaging the front face and includes end sections connected to the main section that wrap around the ends and cover the ends and that extend to the mounts. The corner sections each includes perimeter walls defining a tubular section that extends to an associated one of the mounts in a direction generally perpendicular to a length of the tubular bumper beam. The tubular sections are constructed to optimally absorb energy upon corner impact against the bumper system and to communicate a portion of any impact energy directly to the mounts.

In yet another aspect of the present invention, a bumper system for vehicles includes a bumper beam having a face defining a forward direction for a vehicle and having open ends positioned close to front corners of a vehicle. An energy absorber engages the face and includes a front wall extending generally parallel the face. The energy absorber, when in a vehicle-mounted position, is symmetrically shaped about a transverse vertical central plane, and has a center section engaging the face and covering the face, and further has corner sections covering the open ends of the bumper beam. The corner sections are formed in part by perpendicularly extending walls that form an open honeycomb shaped structure and are formed in part by a cantilevered flange supported in cantilever that extends outwardly from the honeycomb shaped structure in a direction generally parallel a front wall of the energy absorber.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is described as utilizing a B-shaped double-tube bumper beam that is rollformed and swept. The present B-shaped bumper beam is sufficiently described herein for a person skilled in the art to understand and practice the present invention, but it is noted that the process and method of making the illustrated B-shaped bumper beam is described in greater detail in Sturrus patent U.S. Pat. No. 5,454,504, if the reader desires such information. It is specifically contemplated that the present invention could be used in combination with a bumper beam having a shallower channel instead of the deep channel illustrated. For example, it is contemplated that the present invention could be made to work on a D-shaped bumper where the bumper beam had a channel extending significantly into a front face of the bumper beam but where the channel does not extend completely to a rear wall of the bumper beam. On the merits, the teachings of U.S. Pat. No. 5,454,504 are incorporated herein in its entirety for the purpose of providing a complete disclosure of the entire bumper system.

Bumper system20(FIG. 1) includes a bumper beam21attached to a vehicle, and an energy absorber22attached to a face of the bumper beam21. The illustrated bumper beam21is attached by brackets20A. Crush towers can also be used to mount the bumper beam. The illustrated beam is rollformed and swept (see Sturrus patent U.S. Pat. No. 5,454,504) and has a continuous B-shaped double-tubular cross section (FIG.3). The double tubes are spaced vertically apart and include top and bottom mid-walls23and24defining a longitudinally-extending channel25along its front surface. A polymeric energy absorber22has a length with multiple top and bottom box-shaped sections27and27′ (not all being the same size or length) that abut the front surface of the bumper beam21. The energy absorber22further includes a plurality of rearwardly-extending nose sections28that extend into the channel25. The nose sections28are trapezoidally-shaped to fit mateably into the channel25, and extend about 50% to 60% of the way to a bottom of the channel25. Where desired, the nose sections28include detents or are shaped to provide sufficient frictional engagement to temporarily retain the energy absorber22on the bumper beam21. The illustrated nose sections28include collapse-controlling kick walls30and31that lie along and abut the top and bottom mid-walls23and24of the bumper beam21. The kick walls30and31are non-parallel and are connected to the box-shaped sections27and27′ so that, upon impact by an object against the bumper system, the kick walls30and31bend in a predictable and preplanned manner and press into the top and bottom mid-walls23and24. During high impact (see FIGS.3and4), the kick walls30and31press with increasing force, resulting in a more consistent and controlled flexure and collapse of the box-shaped sections27of the polymeric energy absorber22and of the tube sections of the metal bumper beam21as a system. The nose sections28are trapped within the channel25, which eliminates the problem of the energy absorber sliding vertically off a face of the bumper beam (which is a problem in some bumper systems using an energy absorber mounted to a face of a bumper beam).

The B-shaped section of the bumper beam21includes, in addition to top and bottom mid-walls23and24, a top wall34, a front upper wall35, a bottom wall36, a front lower wall37, a rearmost rear wall38and a channel-forming rear wall39. The top tube of the bumper beam21is formed by the walls23,34,35, and38. The bottom tube of the bumper beam21is formed by the walls24,36,37, and38. The top and bottom tubes are interconnected by rear walls38and39. Each of these walls23-24and34-39can be flat or non-flat. For example, in some bumper systems (such as the illustrated walls23-24), it has been found to be beneficial to make the horizontal walls23,24,34, and36slightly bent or curved, both for purposes of providing a bumper beam that is less likely to prematurely kink and more likely to reliably and consistently bend, but also for the purpose of ease of manufacture of the bumper beam. As illustrated, the mid-walls23and24include front portions that are angled to created a tapered throat into which the nose sections28of the energy absorber22tend to move upon impact. The mid-walls23and24also include relatively flat rear portions that are generally parallel. It is noted that, upon a low force impact, the energy absorber22may move partially into this throat (seeFIGS. 4-6) and, if sufficient energy is absorbed during the low energy impact, may return to an original shape without substantial deformation or damage to the vehicle or the bumper system.

The energy absorber22(FIG. 3) is a molded component of non-foam polymer, such as a blend of PC/ABS/PBT. For example, it is contemplated that General Electric's XENOY polymer will work for this purpose. As noted above, the energy absorber22includes top and bottom box-shaped sections27and27′ that abut a front of the front walls35and37. The top box-shaped sections27engaging the top front wall35can be shaped slightly different than the bottom box-shaped sections27′ that engage the bottom front wall37, if desired, but in the presently disclosed preferred embodiment, they are similar in size and shape to better assure a uniform and balanced collapse upon impact. The top box-shaped sections27include a front wall41, open rear area42, top wall43and bottom wall44, as well as end walls45and46that tie the walls41,43-44together. The bottom box-shaped sections27′ include similar walls41′-46′. Walls46A,46B, and46C extend between and interconnect the top and bottom box-shaped sections27and27′. It is noted that the top and bottom walls43,44,43′, and44′, when viewed from a position in front of the bumper system, can be wavy or otherwise nonlinear and non-flat in shape. This provides the top and bottom walls43,44,43′, and44′ with increased strength for resisting buckling, and also helps eliminate distortions such as snaking that occur when molding a long part. It is also noted that the surfaces defined by the front walls and rear areas41,42,41′, and42′ (and potentially the top and bottom walls43,44,43′ and44′) are discontinuous and further include apertures to prevent die lock when molding. (i.e. They include apertures to allow mold tooling to pass through the plane of one wall to form another wall.) In a preferred form, the apertures are sufficient in size so that the molding dies do not require slides or pulls. In other words, the energy absorber22can be made by using hard male and female molds, neither of which require secondary movable die components for creating blind surfaces.

The nose sections28(FIG. 4) include kick walls30and31, and further include a connector wall48that interconnects the leading (rear-most) ends of the kick walls30and31. The connector wall48is located halfway into channel25so that it acts as a guide during impact to guide the leading ends of the kick walls30and31into the channel25. Specifically, the connector wall48is positioned about 30% to 80% of the way into the channel25, or more particularly about 50% to 60% into the channel25. This results in the energy absorber22being able to absorb significant energy, such as may be incurred in a low energy impact. Specifically, in a low energy impact (FIG.4), the energy absorber22absorbs a majority of the energy of the impact energy, and the energy absorber22and the bumper beam21do not permanently deform. In an intermediate energy impact (FIG.5), the energy absorber22deforms substantially, potentially taking on a permanent deformation. However, the bumper beam21deflects and absorbs energy, but the mid-walls23and24only temporarily flex and do not permanently deform. In a high-energy impact (see FIG.6), the kick walls30and31cause the mid-walls23and24to buckle as they approach a maximum amount of deflection. Both the energy absorber22and the bumper beam21permanently deform. The point of buckling is designed into the bumper system20to cause a two-step collapse (FIGS. 5-6) so that a maximum amount of energy is absorbed without damaging the vehicle, while considering all relevant factors such as preferred de-accelerations, occupant safety, government standards, and the like.

The top kick wall30(FIG. 4) includes a root region50that connects to the bottom wall44of the top box section27, and the bottom kick wall31includes a root region51that connects to the top wall43′ of the bottom box section27′. This direct connection allows the nose section28to react quickly and directly to an impact, because the impact energy is transferred directly through the bottom wall44of the box section27to the kick wall30, and because the impact energy is transferred directly through the top wall43′ of the bottom box section27′ to the kick wall31. Due to walls42, the natural flow of material at50and51during impact cause the material to move into walls30and31along directions A and B, respectively (see FIG.5).

A top flange53(FIG. 4) extends rearwardly from the top box section27, and a bottom flange54extends rearwardly from the bottom box section27′. The flanges53and54engage top and bottom surfaces on the bumper beam21. Optionally, the flanges53and54can include attachment tabs or hooks for engaging apertures or features in the bumper beam21for retaining (temporarily or permanently) to the bumper beam21. The illustrated flanges53and54include fingertip-like pads53′ and54′ that frictionally engage top and bottom surfaces of the bumper beam21. These frictional flanges53and54are advantageous in that all (or most) fasteners can be eliminated. It is also noted that hooks may extend through holes in the faces35and37of the bumper beam21and retain the energy absorber22on the beam21.

It is noted that the present arrangement (see FIGS.3and4-6) “reverses” the B-shaped cross section of the bumper beam21relative to the vehicle that it is attached to, which creates a usable energy absorbing crush space within the channel of the bumper beam21. Previously, B-shaped bumper beams were typically used with the flat side of the B shape facing forwardly and supporting the energy absorber. However, with the flat side of the B shape facing forwardly, the known energy absorbers can only collapse against the flat side. Thus, energy absorption is more limited than in the present design. Specifically, the present arrangement ofFIGS. 4-6provides for a more controlled and predictable two-stage energy absorption upon impact, because the energy absorber kick walls30and31stabilize the walls23and24of the bumper beam21during initial impact. Further, the arrangement causes the nose section28to slide into the channel of the bumper beam21, providing an intermediate step of energy absorption, which helps in reading sensor outputs for sensing impacts, such as are used for air bag deployment. Still further, it is believed to be novel to utilize wall structure in an energy absorber to “kick” out and cause predictable collapse of a steel bumper beam (see FIG.6), as in the present invention described above.

It is contemplated that corner sections can be molded onto ends of the energy absorber22or integrally formed as part of the energy absorber. Advantageously, the corner sections can be specifically designed to satisfy a variety of functional and aesthetic conditions. For example, the corner sections can be square-shaped and can be molded with any amount of wall thickness and ribs desired, such that substantially increased amount of corner impact loading can be successfully dissipated by the corner section. Alternatively, a different polymeric material can be molded onto ends of the energy absorber to create the corner section, such as a glass reinforced stiffer polymeric material.

FIGS. 8-9show a bumper system200including a D-shaped single-tube bumper beam201supported on mounting towers202, and an energy absorber203that functions similar to the bumper beam20and energy absorber21discussed above. The bumper beam201includes two spaced apertures204in its front surface205, and the energy absorber203includes rearwardly projecting nose sections206that project through the apertures204and that extend to the rear wall207of the bumper beam201. The illustrated nose sections206abut the rear wall207, but it is noted that they can terminate short of the rear wall207to provide a stepped crush stroke that provides different levels of energy absorption at different impact stroke depths. It is contemplated that more or less apertures204and nose sections206can be used. During a vehicle impact, the nose sections206provide an initial level of impact strength and energy absorption. As the impact stroke increases, the nose sections206buckle outwardly, and engage top and bottom walls of the bumper beam201. An advantage of the bumper system200is that it provides good localized control and a consistent and repeatable energy absorption over energy absorption during impact.

Prior art (FIGS. 7-7B) includes a B-shaped bumper beam221, miter cut at an angle along a line222, with a flat plate223welded onto the cut end to provide an extended flat front surface having an increased angle at the miter cut end. A foam energy absorber224is positioned against the flat front surface of the bumper beam221, and extends onto the flat plate223. The arrangement below eliminates the need to miter cut ends of a bumper beam, which is advantageous because miter cutting is an expensive secondary operation that takes time, money, equipment, and results in increased inventories. The invention described below eliminates the miter cutting and secondary operations needed in the bumper system221/222.

MODIFICATION

Bumper system100(FIG. 10) includes a B-shaped bumper beam101and an energy absorber102attached to the beam's “flat” front face. The energy absorber102incorporates box-shaped sections similar to the concept of the energy absorber22previously described, but does so in a manner permitting the energy absorber102to be used on the “flat” side of the B-shaped bumper beam101(i.e. the side of the B-shaped bumper beam101that does not have a channel formed in it (see FIGS.18and20)), as described below. Also, the energy absorber102can be used on a D-shaped or single tube bumper beam.

The bumper beam101has the same shape and walls as the bumper beam21, except that the bumper beam101has an opposite longitudinal curvature for matching an aerodynamically-shaped curved front of a vehicle. In the beam101, the longitudinal curvature places the “flat” surface103(FIG. 20) on a front side of the bumper beam101, and the two tube sections104and105and the channel106therebetween on a rear side of the beam101. Two mounting brackets or plates107and108(FIG. 10) are attached to the tube sections104and105. The mounting plates107and108each have a flat plate section109that engages and is welded to a back side of the tube sections104and105. A section110(FIG. 13) extends from the mounting plates107and108at a location about 1 inch to 1½ inches from an end of the tube sections104and105. The sections110each include an outer leg112that extends rearward of the plate section109, generally at a corner of the vehicle. It is contemplated that the mounting plates107and108can have a forward loop111that partially covers an end surface of the energy absorber if desired (see FIG.25). Coplanar flanges113and114(FIG. 13) extend from the rear/outer ends of the brackets107and108. It is noted that other mounting systems can be used for vehicle attachment on the present bumper system if desired.

The energy absorber102is symmetrical about a centerline115(FIG.12A), with each half of the energy absorber102including four box-shaped sections117-120, each being interconnected by longitudinally-extending walls, as described below. The box-shaped section117(FIG. 12A) is adjacent the centerline115and includes a front face wall121, a top wall122, a bottom wall123, an inboard sidewall124and an outboard sidewall125. A rear of the box-shaped section117is open and the walls122-125have draft angles, so that the box-shaped section117can be formed on molding dies that do not require die pulls or other moving parts for forming blind surfaces. Two large “crush-initiator” apertures126(FIG. 15) are formed in the inboard sidewall124to weaken the box-shaped section117, to provide for an optimal crush stroke upon impact against the bumper system100and specifically to provide for optimal energy absorption during the crush stoke. The illustrated apertures126are each about ⅓ of a total height of the inboard sidewall124(see FIG.18), are located at a top third and a bottom third of the sidewall124, and extend to a full depth of the sidewall124. Different shapes of apertures can be used. The illustrated apertures126are not rectangular, but instead have at least one curved edge126′, which is designed to initiate a controlled crush during an impact for optimal energy absorption during impact, and which is also designed to facilitate molding. A strip of material between the apertures126and also the strips of material above and below the apertures126form the structure of sidewall124. Apertures127(FIG. 15) are also formed on the front face wall121as desired, such as to reduce mass, improve tooling, and provide clearances and attachments to fascia. The outboard sidewall125has a C-shaped profile (when viewed in a car-mounted position), and has a vertical center portion128that is located closer to the centerline115than the upper and lower portions. A top angled portion129of the front face wall121slopes rearwardly from a remainder of the vertical front face wall121, which is more vertically oriented, but not perfectly vertical.

The box-shaped section118(FIG. 12A) is adjacent the box-shaped section117and includes a front face wall131, a top wall132, a bottom wall133, an inboard sidewall134and an outboard sidewall135. The box-shaped section118is about double a width of the box-shaped section117(in a longitudinal direction), and the inboard sidewall135is C-shaped to a longitudinal width about double the dimension of the C-shape of the outboard sidewall124of the center box-shaped section117. Also, a top angled portion139of the front face wall131has a vertical dimension that is slightly less than the top angled portion129of the center box-shaped section117, so that the combined front face of the energy absorber matches a shape of the fascia panel placed on it. The outboard sidewall135(FIG. 17) has three apertures136that are similar to the apertures126found in the sidewall124described above, with the exception that one of the apertures136is formed in each third of the outboard sidewall135.

The box-shaped section119(FIG. 12A) is adjacent the box-shaped section118and includes a front face wall141, a top wall142, a bottom wall143, an inboard sidewall144and an outboard sidewall145. The box-shaped section119is about ⅔ of a width of the box-shaped section118(in a longitudinal direction). The inboard and outboard sidewalls144and145are relatively flat (i.e. are not C-shaped). Also, a top angled portion149of the front face wall141has a vertical dimension that is slightly less than the top angled portion139of the box-shaped section118, so that the combined front face of the energy absorber matches a shape of the fascia panel placed on it. The inboard and outboard sidewalls144and145each have two apertures146(FIG. 20) that are similar to the apertures126found in the sidewall124described above, with the exception that the inboard sidewall144also has a center aperture146.

The box-shaped section120(FIG. 12A) is adjacent the box-shaped section119and includes a front face wall151, a top wall152, a bottom wall153, an inboard sidewall154and an outboard sidewall155. The box-shaped section120is about equal in width to the box-shaped section117(in a longitudinal direction). The inboard and outboard sidewalls154and155are relatively flat (i.e. are not C-shaped). Also, the front face wall151extends to a top of the box shaped section120, and there is not a top angled portion like the other box-shaped sections117-119. The inboard sidewall154has two apertures156that are similar to the apertures126found in the sidewall124described above. The illustrated box-shaped section120is actually divided into vertically-spaced-apart halves, and consistent with that the front face wall151and also the inboard and outboard sidewalls154and155are actually divided into top and bottom halves, with the center section being entirely open except for a vertical stabilizing rib157.

The illustrated box-shaped sections117-120are connected together by interconnecting “honeycomb-shaped” structures in the form of four horizontal ribs160-163(FIG. 12A) that are spaced equally apart in a vertical direction. It is contemplated that the box-shaped sections117-120can be connected together by different arrangements and still incorporate many of the advantages of the present energy absorber. The top rib160and the bottom rib163extend continuously from end to end of the energy absorber102. The middle two ribs161and162also extend end to end of the energy absorber102, with the exception that the middle ribs161and162are discontinued near the centerline115and do not connect the two center box-shaped sections117. Also, the ribs161and162connect the top and bottom legs of the C-shaped inner portion of walls125and134. The box-shaped sections117-120are also connected together by a rear wall164. The rear wall164completely covers a rear of the energy absorber102, with the exception that an opening is formed in the rear wall164at each of the box-shaped sections117-120to facilitate tooling and prevent a die lock condition. The rear wall164not only ties the sections117-120together, but also forms vertical straps that tie the top and bottom walls together to prevent the top and bottom walls from spreading apart during an impact. This also eliminates the need for top and bottom fasteners.

A top flange170(FIG. 13) and a bottom flange171(FIG. 14) are formed on top and bottom edges of the rear wall164. The flanges170and171wrap onto tops and bottoms of the bumper beam101. Fingertip-like pads172are formed on the flanges170and171for engaging mating areas on the top surface and on the bottom surface of the bumper beam101to temporarily frictionally retain the energy absorber102on the bumper beam101. Also, hooks173(FIGS. 10-11) are formed on tabs that extend from (and co-planar with) the top and bottom walls122,123,132,133,142,143,152, and153. The hooks173are shaped to engage mating holes in a front face of the bumper beam101. The hooks173(and also flanges53-54) provide an opportunity for “blind” snap-attachment, such as when an operator has preassembled an energy absorber to a fascia, and then attaches the assembled absorber/fascia as a unit to a vehicle front. In such event, the fascia prevents the operator from attaching the absorber to a bumper beam.

The energy absorber102(FIG. 11) includes integrally-formed end sections180and181that are symmetrically shaped and that are optimally shaped to form end-located crush boxes for energy absorption upon corner impact to a vehicle. The end sections180and181each include a vertical rib182(FIG. 12A) that transversely crosses and connects to the horizontal ribs160-163to form a honeycomb shape. The outboard sidewall155is extended rearwardly so that it substantially covers the open end of the tube sections on the bumper beam101. Also, the rear wall164is extended at a location164′ (FIGS. 22,24, and25) from the outboard sidewall155to form a rearwardly extending box164″ (FIG. 25) that fits adjacent an end of the bumper beam. It is noted that the mounting brackets107and108can include a forward loop111that holds the box164″ in place against an end of the bumper beam, if desired. A crescent-shaped flange183extends coplanar with the face front walls121,131,141, and151. The flange183is stiff but flexible, such that it does a good job of supporting front-end fascia, such as RIM urethane fascia, placed on it. At the same time, the flange183is flexible for flexing during a corner impact on a vehicle, thus reducing damage to the vehicle.

The illustrated top and bottom walls122,123,132,133,142,143,152, and153are wave-shaped or corrugated in shape to facilitate molding and strength. The illustrated walls of the box-shaped sections117-120and walls160-163and adjacent areas are about 2 mm thick, while the walls of the end sections180and181are about 3 to 4 mm thick. (CompareFIGS. 16-20to theFIGS. 22-25.) However, it is contemplated that the walls and thickness can be made any thickness, including localized variations made to optimize the energy absorption. Since the mold dies are relatively non-complex (since pulls and movable components for making blind surfaces are not required), the walls can be made thicker relatively easily by grinding away metal in the molding dies. Also, the apertures can be made smaller by grinding away metal, such that the crush/impact strength can be closely and accurately controlled, and also can be carefully adjusted and tuned to react to the actual results of vehicle crash testing during bumper development for a particular model vehicle. For example, by reviewing the energy absorber102and bumper beam101after an impact (compareFIGS. 20 and 22which are before impact, andFIGS. 21 and 23which are after impact), intelligent decisions can be made regarding what areas of the energy absorber102require additional strength, and what areas need to be weakened. For example, by changing a shape of the curved edge of the apertures126,136,146and156, a different energy absorption curve results on a force vs deflection graph of a vehicle impact. Specifically, the rates of increase in energy absorption can be controlled and more accurately adjusted while “tweaking” and fine-tuning the energy absorber102. Substitution of different material blends in the energy absorber102also can help.

In particular, it is noted that the end sections180and181of the present energy absorber102form integral box-shaped sections that provide a very consistent and strong corner impact strength. The honeycomb shape formed by ribs160-163and ribs153and182along with the crescent-shaped flange183and the interaction of the end sections180-181with the J-shaped section110of the mounting bracket107and108and the end of the tube sections104and105of the bumper beam101are important aspects of the present invention. Also, an important inventive aspect is the concept of fine-tuning the energy absorber102by changing wall thicknesses and providing apertures of different sizes to optimize a bumper system.

Yet another important feature of the present illustrated design of the energy absorber102is shown by the offset163A in lower wall163, which connects the front and rear portions163B and163C of wall163. During impact, the front portion163B telescopes overlappingly onto the rear portion163C, with the offset163A wrapping back upon itself and between the portions163B and163C. This “wrapping” action provides high energy absorption and a very consistent and predictable collapse, which is very desirable in energy absorbers.

It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise. Further, it is to be understood that methods related to the above concepts are believed to be within a scope of the present invention.