Automotive rail/frame energy management system

CLAIM OF BENEFIT OF FILING DATE

The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/333,273 filed Nov. 14, 2001.

FIELD OF THE INVENTION

The present invention relates generally to an energy management system for placement in different portions or structural cavities of an occupant transportation vehicle for the management, direction, and absorption of energy. More particularly, the present invention relates to a reinforcing energy management structure for use in an automotive rail, such as a frame, front rail, or other chosen portion of an automotive vehicle, which can be selectively tuned or targeted to help absorb, direct, and/or transfer energy in the vehicle body.

BACKGROUND OF THE INVENTION

For many years the transportation industry has been concerned with designing structural members that do not add significantly to the weight of a vehicle. At the same time, automotive applications require structural members capable of providing reinforcement to targeted portions of the vehicle and permit ingress and egress to the passenger compartment in the event of a collision or other impact event. While the devices found in the prior art may be advantageous in many applications, the prior art methods typically require the use of additional manufacturing processes and steps in either a supplier facility, a pre-production manufacturer stamping facility, or the final vehicle assembly planet which often increases labor demand, cycle time, capital expense, and/or required maintenance clean-up. Accordingly, there is needed a simple, low cost structure or system for reinforcing vehicle rails, such as a front rail or frame member, which reinforces the vehicle, enhances structural integrity, and can be efficiently incorporated into the vehicle manufacturing process. In addition, there is also a need for a relatively low cost system or structure which provides reinforcement and inhibits distortion to the frame or front rail structures in a vehicle, and which can serve to manage energy in a frontal/offset impact to the vehicle by reinforcing the frame member or front rail to help target applied loads and help redirect or tune energy management of deformation.

SUMMARY OF THE INVENTION

The object of the present invention is to redirect applied loads and manage impact energy by placing a reinforcement system in targeted areas of an automotive rail, frame member, or other portion of a vehicle. The system generally employs at least one member or insert, which is attached or adhered to the chosen portion of the vehicle such as a frame or rail or any other portion of an automotive vehicle selected to inhibit deformation in the event of impact to the vehicle. The member may also comprise a plurality of members suitable for receiving an application of an expandable or non-expandable reinforcing material coated, disposed, or placed over at least a portion of an exterior surface of the member or members. The reinforcing material disposed on the member is capable of activation when exposed to heat typically encountered in an automotive paint operation, such as e-coat and other paint cycles in a vehicle assembly plant. It is contemplated that the reinforcing material disclosed in the present invention, activates, optionally expands, and then adheres, cures, or bonds thereby structurally reinforcing and enhancing the strength and stiffness of the frame or front rail to redirect applied loads and energy. In one embodiment, the material is heat expandable and at least partially fills a cavity defined by the rail, frame, or selected portion of the vehicle by structurally adhering the rail and the frame depending upon the size and shape of the cavity, during the e-coat bake operation. In another embodiment, the reinforcing material is a melt flowable material comprising one or more components, which upon the application of heat will spread over a surface. The selected reinforcing material may also provide a variety of characteristics including structural reinforcement, stress-strain reduction, vibrational damping, noise reduction, or any combination thereof. In an alternative embodiment, the reinforcing material may be non-expandable or otherwise suitable for filling a defined volume or space within the selected insert or member.

In a particular preferred embodiment, the present invention further serves to manage crash energy typically encountered during frontal impact testing of an automotive vehicle. More specifically, the member or insert of the present invention may contain at least one and preferably a plurality of triggers consisting of notches, holes, or any other form of step change or alteration to the geometry of an internal or inner portion or portions of the member. The internal triggers of the present invention effectively target and direct axial bending to selected portions of the system and allow management of crash energy typically encountered during front offset testing. The system of the present invention further comprises a reinforcing or bonding material disposed over at least a portion of the member which can be extruded, molded, or “mini-application” bonded onto the member in either a pre-production setting, such as a stamping facility, or during the final assembly operation. The member, and the selected bonding or expandable material, is installed in the selected frame or rail prior to the e-coat or paint operation processing. Hence, the present invention provides flexibility in the manufacturing process since it can be utilized by either the frame or front rail manufacturer/supplier or the final vehicle manufacturer with reduced labor, capitol expense, maintenance requirements, and floor space demand. Once the reinfocing material bonds and cures to the selected rail or frame portion of the vehicle, distortion of the frame or front rail may be inhibited or managed during a frontal/offset impact event or any other application of impact energy to the exterior of the vehicle. By absorbing and/or transferring certain impact energy and providing reinforcement to the frame or rail portion of the vehicle, the present invention provides a system for managing deformation to the vehicle in the event of a frontal/offset impact.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims and drawings, of which the following is a brief description:

<figref idref="DRAWINGS">FIG. 1</figref> is an isometric view of a partially exploded automotive frame rail showing the energy management enhancement system in accordance with the teachings of the present invention.

<figref idref="DRAWINGS">FIG. 1</figref>(<i>a</i>) is an exposed view of a portion of a reinforcement system typically found in the prior art depicting the three crush zones typically associated with frontal energy management structures in the automotive industry and further depicting the use of external triggers disposed on the exterior portion of a member known in the art.

<figref idref="DRAWINGS">FIG. 2</figref> is an exposed view of a portion of the present invention depicted in an automotive space frame architecture or body-in-white design showing the position of the at least one member with the reinforcing material in the uncured state attached to rail of an automotive vehicle.

<figref idref="DRAWINGS">FIG. 3</figref> is a portion of the system described in <figref idref="DRAWINGS">FIG. 1</figref>, showing an alternative embodiment of the at least one member of the present invention with the reinforcinge material in the uncured state prior to attachment to the frame or rail of an automotive vehicle and further showing the attachment means of the present invention in the form of a clip assembly.

<figref idref="DRAWINGS">FIG. 4</figref> is a portion of the system described in <figref idref="DRAWINGS">FIG. 1</figref>, showing an alternative embodiment of the at least one member of the present invention with the reinforcing material in the uncured state prior to attachment to the frame or rail of an automotive vehicle.

<figref idref="DRAWINGS">FIG. 5</figref> is a portion of the system described in <figref idref="DRAWINGS">FIG. 1</figref>, showing an alternative embodiment of the at least one member of the present invention with the reinforcing material in the uncured state prior to attachment to the frame or rail of an automotive vehicle.

<figref idref="DRAWINGS">FIG. 6</figref> is a portion of the system described in <figref idref="DRAWINGS">FIG. 1</figref>, showing an alternative embodiment of the at least one member of the present invention with the reinforcing material in the uncured state prior to attachment to the frame or rail of an automotive vehicle.

<figref idref="DRAWINGS">FIG. 7</figref> is an exploded perspective view of the present invention, showing an alternative embodiment of the system disposed within a closed form wherein the plurality of members are inter-locking and retained by a third member also incorporating a self-locking mechanism and the trigger of the present invention is depicted as a hole extending through the interior portion of the member.

<figref idref="DRAWINGS">FIG. 8</figref> is an exploded perspective view of the automotive rail reinforcement system of the present invention prior to the impact of energy typically encountered in frontal impact testing of an automotive vehicle.

<figref idref="DRAWINGS">FIG. 9</figref> is an exploded perspective view of the automotive rail reinforcement system of the present invention after the impact of energy typically encountered in frontal impact testing of an automotive vehicle and the effect of axial bending to the system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to methods and systems for managing energy and reducing impact deformation characteristics of automotive vehicles in the event of a frontal/offset impact event to the vehicle. More particularly, the present invention relates to a system for reinforcing, directing impact energy, and tuning the management of said impact energy to portions of an automotive vehicle, such as a frame or rail, which effectuates the reduction and inhibition of physical deformation or structural movement to the occupant compartment in the event of an impact to the exterior of the vehicle from another object. The system absorbs, dissipates and/or transfers the impact energy to reduce and inhibit the resulting deformation to the automotive vehicle. A reduction in impact deformation to the vehicle may serve to allow continued passenger ingress and egress to the vehicle after an impact event and reduce repair time and costs.

The automotive industry generally utilizes two primary modes for frontal impact testing of vehicles: full and offset. Full frontal impact testing is utilized in the United States for both federal compliance and assessment testing. While these tests are typically performed at different speeds (i.e. approximately 30 mph for compliance and 35 mph for assessment), they both relate to impact of a barrier utilizing the full width of the front end structure of the tested vehicle. The primary goal of these tests is to assess occupant responses (femur loads, head injury criteria, chest deceleration, etc.) and validate the vehicle restraint systems (seatbelts, airbags, etc.). The offset impact test is typically performed at 40 mph with typically only 40% of the front end of the tested vehicle impacting the barrier. One of the primary goals of the offset impact test is to assess the structural integrity of the vehicle structure itself.

Design for frontal crash energy management is a multidisciplinary process. Crash energy management is typically performed through a combination of the vehicle structure and restraint systems. Many automotive manufacturers seek vehicle structures that can be designed to absorb energy. Structural efficiency, defined as the ability to optimize energy management as a vehicle structure deforms upon impact, depends upon the configuration of the design. For purposes of frontal impact testing, the severe crush loads created by the impact of energy managing structures tend to decelerate the occupant compartment. The ability of the energy managing structures to transfer manageable loads to an occupant compartment, coupled with the ability of the restraint system(s) to effectively dissipate such loads, may help dictate how well the occupant compartment responds to extreme loading, as well as how the compartment sustains minimal deformation and intrusion under certain conditions. For these reasons, the prior art focuses on at least two major considerations in the design of vehicle structures for crash energy management: (1) the absorption of kinetic energy of the vehicle, and (2) the crash resistance or strength needed to sustain the crush process inherent to the testing process and maintain passenger compartment integrity.

Traditional frontal energy management structures of automotive vehicles generally consist of three distinct crush zones. First, there will be a soft zone, typically the bumper area or other exterior fascia, followed by two stiffer zones moving inwardly towards the occupant compartment. As defined and discussed herein, the two stiffer zones shall be referred to as primary and secondary. The primary crush zone is traditionally located immediately behind or adjacent to the soft crush zone, such as the bumper system of a vehicle, but in front of the powertrain compartment of a vehicle. The secondary crush zone is typically defined as the region bridging or tying the primary crush zone to the occupant compartment of the vehicle. For framed vehicles, such as trucks and larger automobiles, the secondary crush zone typically extends to the front body mount, as shown in <figref idref="DRAWINGS">FIG. 1</figref><i>a</i>. For smaller vehicles, the frame can be integrated into the body-in-white design. This type of design is known in the art as space-frame architecture as shown in <figref idref="DRAWINGS">FIG. 2</figref>. In the case of space-frame vehicle structures, the secondary crush zone extends rearward bridging or tying the primary crush zone to the vehicle firewall and toe-board areas of the occupant compartment. Due to the proximity of the secondary crush zone to the occupant compartment of the vehicle, design requirements and energy management control techniques need to be utilized to minimize potential intrusion into the occupant compartment.

Accordingly, a main goal of the crush zone technology known in the art, is to manage the maximum amount of energy without compromising the integrity of the occupant compartment. The present invention addresses these needs through an energy management system and structure which provides a stable platform or system for the progressive collapsing of the primary crush zone. Namely, as shown at <figref idref="DRAWINGS">FIGS. 8 and 9</figref>, the present invention provides stability to the secondary crush zone which inhibits buckling or deformation while the primary crush zone is being crushed so that the overall structure is progressively collapsed in a predetermined and managed manner. As depicted in <figref idref="DRAWINGS">FIGS. 8 and 9</figref>, the present invention may comprise a plurality of triggers to effectuate axial collapse by creating opposing or dual bending modes. The system or structure of the present invention further serves to manage crash energy by attempting to control the deformation characteristics of either or both of the primary and secondary crush zones in such a way to minimize occupant compartment intrusion.

As is well known in the art, energy management structures deform (collapse) in a combination of axial and bending modes. Many existing energy management systems utilize the bending mode which results in lower energy management capabilities. For instance, since the bending mode is less efficient from an energy management standpoint, it typically requires much heavier designs or reinforcement configurations to manage the same amount and type of energy as an axially collapsing design. In most designs where weight is a criteria in vehicle design and performance, the axial mode is the preferred method of energy management. The bending mode, which involves the formation of localized hinge mechanisms and linkage type kinematics, is also a lower energy mode. For example, a structure will have a tendency to collapse in a bending mode due to the lower energy mode. Based upon this, even a structure specifically designed for axial collapse will default to the bending mode unless other structural features are provided in the design to enhance stability and resistance to off-angle loading.

Axial folding is also considered to be the most effective mechanism of energy absorption. It is also the most difficult to achieve due to potential instability and the lower energy default to the bending mode. The energy management system or structure of the present invention seeks to maximize axial collapse of portions of an automotive vehicle, while minimizing bending, through the use of at least one, and preferably a plurality of triggers designed within targeted portions of either or both of the primary and secondary crush zones. The trigger or triggers of the present invention are defined as a change or discontinuity in the part geometry of either or both of the primary and secondary crush zones forming the structure of the present invention designed to create stress risers to cause localized bending. A plurality of triggers, or combinations of different geometrically designed triggers, are utilized in the present invention to initiate folds in the structure inducing axial collapse in targeted portions of at least one of the three distinct crush zones of the frontal energy management structure shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>. The triggers of the present invention are sized and designed to ensure that axial collapse of the structure shown at <figref idref="DRAWINGS">FIGS. 1 and 2</figref> can occur at sufficiently high loads in order to maximize the amount of energy managed by the structure or the amount of energy typically encountered in frontal impact testing.

Triggers currently found in the prior art have generally been modifications to the exterior portions of metal structural reinforcement members or inserts used to reinforce a chosen body portion or cavity of an automotive vehicle, such as a rail, pillar, cross-member, etc., as well as any other area immediately adjacent to the occupant compartment of an automotive vehicle. These prior art triggers typically consist of holes or part contours to the exterior portion of the structural reinforcement member or insert. However, through modifications to the internal or inner portions of a member or insert, the present invention provides at least one, and preferably a plurality of internal triggers for use in managing energy typically encountered by an automotive vehicle during frontal impact testing. The internal triggers of the present invention effectively target and direct axial bending to selected portions of the structure and can comprise notches, holes, or any other form of step change or alteration to the geometry of an inner portion or portions of the structural reinforcement member or insert. For example, the structural reinforcement member or insert of the present invention, serves a plurality of purposes and provides a method for managing impact energy. First, the member or insert acts as a stabilizer which reinforces the secondary crush zone thereby allowing the primary crush zone to maximize axial crush. Once the primary crush zone has achieved maximum ability to absorb impact energy, the secondary crush zone of the structure of the present invention must be designed to absorb some additional energy as a means to reduce deformation to the occupant compartment of the vehicle. The structure of the present invention, utilizing a plurality of triggers such as notches or a cut-away section of the member or insert, serves to initiate bending of the structure based upon its existing geometry.

In one embodiment of the present invention, at least one insert or member <b>12</b> is placed within, attached, affixed, or adhered to at least a portion of a frame or rail of an automotive vehicle wherein at least one member <b>12</b> includes an expandable or reinforcing material <b>14</b> supported by, and disposed along portions of the member <b>12</b>. The member <b>12</b> has an interior and an exterior portion and may be configured in any shape, design, or thickness corresponding to the dimensions of the selected frame or rail of the vehicle and may further comprise a plurality of triggers <b>20</b> integrated within an interior portion of the member <b>12</b>, which are designed and incorporated to specifically tune or target impact energy for either absorption or redirection to other portions of the vehicle. The reinforcing material <b>14</b> extends along at least a portion of the length of the exterior portion of the member <b>12</b>, and may fill at least a portion of a cavity or space defined within the frame or rail <b>16</b>. It is contemplated that the triggers <b>20</b> of the present invention may comprise a notch or cut-away portion of the selected member <b>12</b> that may or may not have an amount of reinforcing material <b>14</b> disposed over trigger or triggers <b>20</b>.

The system <b>10</b> generally employs at least one member <b>12</b> adapted for stiffening the structure to be reinforced, such as a frame or front rail <b>16</b> found in automotive vehicles, and helping to better manage impact energy typically encountered in a frontal/offset impact to the vehicle. In use, the member or members <b>12</b> are disposed within or mechanically attached, snap-fit, affixed, or adhered by an adhesive or other adhering material onto at least a portion of the chosen frame or front rail <b>16</b> with the reinforcing material <b>14</b> serving as a load transferring, energy absorbing medium disposed along at least one exterior surface of the member <b>12</b>. In one embodiment, the member or members <b>12</b> are comprised of a molded polymeric carrier, an injection molded polymer, graphite, carbon, or a molded metal such as aluminum, magnesium, or titanium as well as an alloy derived from the materials or a foam derived from the materials or other metallic foam and is at least partially coated with a reinforcing material <b>14</b> on at least one of its sides, and in some instances on four or more sides.

In addition, it is contemplated that the member <b>12</b> could comprise a nylon or other polymeric material as set forth in commonly owned U.S. Pat. No. 6,103,341, expressly incorporated by reference herein, as well as injection molded, extruded, die cast, or machined member comprising materials such as polysulfone, polyamides (e.g.), nylon, PBI, or PEI. The member or members <b>12</b> may also be selected from materials consisting of aluminum, extruded aluminum, aluminum foam, magnesium, magnesium alloys, molded magnesium alloys, titanium, titanium alloys, molded titanium alloys, polyurethanes, polyurethane composites, low density solid fillers, and formed SMC and BMC. Still further, the member <b>12</b> adapted for stiffening the structure to be reinforced could comprise a stamped and formed cold-rolled steel, a stamped and formed high strength low alloy steel, a roll formed cold rolled steel, or a roll formed high strength low alloy steel.

Still further, it will be appreciated that the insert or member <b>12</b> used in the present invention, as well as the material forming the geometric step-changes or triggers <b>20</b> found in the member <b>12</b> of the present invention, may comprise a reactive or non-reactive material, which yields high compressive strength and moduli and may either form the carrier or member itself or be capable of filling or coating the insert or member <b>12</b>. Generally speaking, the member <b>12</b> may be composed of a material which exhibits such higher compressive strength and moduli may be selected from the group consisting of a syntactic foam, syntactic-type foams with low density or reinforcing fillers (e.g., carbon fillers, carbon fibers, carbon powder, and materials sold under the trade name KEVLAR), spheres, hollow spheres, ceramic spheres, aluminum pellets, and fibers, such as glass fibers, wood fibers, or other space filling fibrous materials, including pelletized and extruded formulations thereof. In addition, the insert or member <b>12</b> may comprise a concrete foam, syntactic foam, aluminum foam, aluminum foam pellets, or other metallic foam, as well as alloys thereof. An example of such materials include commonly assigned U.S. Provisional Patent Application Ser. No. 60/398,411 for “Composite Metal Foam Damping/Reinforcement Structure” filed Jul. 25, 2002 and hereby incorporated by reference. Other materials suitable for use as the insert or member <b>12</b> in the present invention include polysulfone, aluminum, aluminum foam, and other metals or metallic foams, concrete, polyurethane, epoxy, phenolic resin, thermoplastics, PET, SMC, and carbon materials sold under the trade name KEVLAR. In addition, it is also contemplated that the insert or member <b>12</b> of the present invention, or portions or volumes defined by the insert or member <b>12</b> of the present invention, may utilize or comprise a material sold under the trade name ISOTRUSS, as described and set forth in U.S. Pat. No. 5,921,048 for a Three-Dimensional Iso-Truss Structure issued Jul. 13, 1999, WO/0210535 for Iso-Truss Structure published by the World Intellectual Property Organization on Feb. 7, 2002, and a pending U.S. provisional patent application before the U.S. Patent &amp; Trademark Office entitled: Method And Apparatus For Fabricating Complex, Composite Structures From Continuous Fibers, all of which have been commonly-assigned to Brigham Young University and are hereby incorporated by reference herein.

It is further contemplated that any number of the suitable materials disclosed and set forth herein for use as the insert or member <b>12</b> of the present invention may be formed, delivered, or placed into a targeted or selected portion of a transportation vehicle (i.e. land, rail, marine, or aerospace vehicle) through a variety of delivery mechanisms and systems that are known in the art. For example, the material may be poured, pumped, stamped, extruded, casted, or molded into any number of desired shapes or geometry depending upon the selected application or area to be reinforced. From a processing or manufacturing standpoint, the selected member <b>12</b> may be injection molded, compression molded, transfer molded, injection-compression molded, blowmolded, reaction injection molded, or thixomolded. Further, the material comprising the member <b>12</b> may be reactive, non-reactive, expandable, or non-expandable and may be further utilized, incorporated, or filled into a hollow core, shell, or blow-molded carrier for later placement within a selected portion of the vehicle during any phase of the pre-manufacturing or manufacturing process.

A number of structural reinforcing foams are known in the art and may be used to produce the reinforcing material <b>14</b> of the present invention. A typical reinforcing material <b>14</b> includes a polymeric base material, such as an epoxy resin or ethylene-based polymer which, when compounded with appropriate ingredients (typically a blowing agent, a curing agent, and perhaps a filler), typically expands and cures in a reliable and predictable manner upon the application of heat or another activation stimulus. The resulting material has a low density and sufficient stiffness to impart desired rigidity to a supported article. From a chemical standpoint for a thermally-activated material, the reinforcing material <b>14</b> is initially processed as a thermoplastic material before curing. After curing, the reinforcing material <b>14</b> typically becomes a thermoset material that is fixed and incapable of flowing.

The reinforcing material <b>14</b> is generally a thermoset material, and preferably a heat-activated epoxy-based resin having foamable characteristics upon activation through the use of heat typically encountered in an e-coat or other automotive paint oven operation. As the reinforcing material <b>14</b> is exposed to heat energy or other energy source, it expands, cross-links, and structurally bonds to adjacent surfaces. An example of a preferred formulation is an epoxy-based material that may include polymer modificis such as an ethylene copolymer or terpolymer that is commercially available from L&amp;L Products, Inc. of Romeo, Mich., under the designations L-5204, L-5206, L-5207, L-5208, L-5209, L-5214, and L-5222. One advantage of the preferred reinforcing material <b>14</b> over prior art materials is the preferred material <b>14</b> can be processed in several ways. Possible processing techniques for the preferred materials include injection molding, blow molding, thermoforming, direct deposition of pelletized materials, extrusion or extrusion with a mini-applicator extruder. This enables the creation of part designs that exceed the design flexibility capability of most prior art materials. In essence, any reinforcing material <b>14</b> that imparts structural reinforcement characteristics may be used in conjunction with the present invention. The choice of the reinforcing material <b>14</b> used will be dictated by performance requirements and economics of the specific application and requirements. Generally speaking, these automotive vehicle applications and selected areas to be reinforced may utilize technology and processes such as those disclosed in U.S. Pat. Nos. 4,922,596, 4,978,562, 5,124,186, and 5,884,960 and commonly assigned U.S. Pat. Nos. 6,467,834, 6,474,723, 6,474,722, 6,471,285, 6,419,305, 6,383,610, 6,358,584, 6,321,793, 6,311,452, 6,296,298, 6,263,635, 6,131,897, as well as commonly-assigned U.S. Application Ser. Nos. 09/524,961 filed Mar. 14, 2000, 60/223,667 filed Aug. 7, 2000, 60/225,126 filed Aug. 14, 2000, Ser. No. 09/676,725 filed Sep. 29, 2000, Ser. No. 10/008,505 for Structural Foam published by the U.S. Patent &amp; Trademark Office on Oct. 31, 2002, and Ser. No. 09/459,756 filed Dec. 10, 1999, all of which are expressly incorporated by reference.

Additional expandable or reinforcing materials <b>14</b> that could be utilized in the present invention include other materials which are suitable as bonding, energy absorbing, or acoustic media and which may be heat activated foams which generally activate and expand to fill a desired cavity or occupy a desired space or function when exposed to temperatures typically encountered in automotive e-coat curing ovens and other paint operation ovens. Though other heat-activated materials are possible, a preferred heat activated material is an expandable or flowable polymeric formulation, and preferably one that can activate to foam, flow, adhere, or otherwise change states when exposed to the heating operation of a typical automotive assembly painting operation. For example, without limitation, in one embodiment, the polymeric foamable material may comprise an ethylene copolymer or terpolymer that may possess an alpha-olefin. As a copolymer or terpolymer, the polymer is composed of two or three different monomers, i.e., small molecules with high chemical reactivity that are capable of linking up with similar molecules. Examples of particularly preferred polymers include ethylene vinyl acetate, EPDM, or a mixture thereof. Without limitation, other examples of preferred foamable formulations commercially available include polymer-based materials available from L&amp;L Products, Inc. of Romeo, Mich., under the designations as L-2018, L-2105, L-2100, L-7005, L-7101, L-7102, L-2411, L-2420, L-4141, etc. and may comprise either open or closed cell polymeric base material.

Further, it is contemplated that the reinforcing material <b>14</b> of the present invention may comprise acoustical damping properties which, when activated through the application of heat, can also assist in the reduction of vibration and noise in the overall automotive frame, rail, and/or body of the vehicle. In this regard, the now reinforced and vibrationally damped frame or front rail <b>16</b> will have increased stiffness which will reduce natural frequencies, that resonate through the automotive chassis thereby reducing transmission, blocking or absorbing noise through the use of the conjunctive acoustic product. By increasing the stiffness and rigidity of the frame or front rail, the amplitude and frequency of the overall noise/vibration that occurs from the operation of the vehicle and is transmitted through the vehicle can be reduced. Although the use of such impact absorbing materials and members are directed to an automotive frame, it is contemplated that the present invention can be utilized in other areas of an automotive vehicles that are used to ensure ingress and egress capability to the vehicle by both passengers as well as cargo, such as closures, fenders, roof systems, and body-in-white (BIW) applications which are well known in the art.

In addition to the use of an acoustically damping material along the member <b>12</b>, the present invention could comprise the use of a combination of an acoustically damping material and a reinforcing material <b>14</b> along different portions or zones of the member <b>12</b> depending upon the requirements of the desired application. Use of acoustic expandable materials in conjunction with a reinforcing material <b>14</b> may provide additional structural improvement but primarily would be incorporated to improve NVH characteristics.

While several materials for fabricating the impact absorbing or reinforcing material <b>14</b> have been disclosed, the material <b>14</b> can be formed of other selected materials that are heat-activated or otherwise activated by an ambient condition (e.g. conductive materials, welding applications, moisture, pressure, time or the like) and expand in a predictable and reliable manner under appropriate conditions for the selected application. One such material is the epoxy based resin disclosed in commonly-assigned U.S. Pat. No. 6,131,897 for Structural Reinforcements, the teachings of which are incorporated herein by reference. Some other possible materials include, but are not limited to, polyolefin materials, copolymers and terpolymers with at least one monomer type an alpha-olefin, phenol/formaldehyde materials, phenoxy materials, polyurethane materials with high glass transition temperatures, and mixtures or composites that may include even metallic foams such as an aluminum foam composition. See also, U.S. Pat. Nos. 5,766,719; 5,755,486; 5,575,526; 5,932,680 (incorporated herein by reference). In general, the desired characteristics of the reinforcing material <b>14</b> include high stiffness, high strength, high glass transition temperature (typically greater than 70 degrees Celsius), and good adhesion retention, particularly in the presence of corrosive or high humidity environments.

In applications where a heat activated, thermally expanding material is employed, an important consideration involved with the selection and formulation of the material comprising the structural foam is the temperature at which a material reaction or expansion, and possibly curing, will take place. In most applications, it is undesirable for the material to activate at room temperature or the ambient temperature in a production line environment. More typically, the structural foam becomes reactive at higher processing temperatures, such as those encountered in an automobile assembly plant, when the foam is processed along with the automobile components at elevated temperatures. While temperatures encountered in an automobile assembly body shop ovens may be in the range of 148.89° C. to 204.44° C. (300° F. to 400° F.), and paint shop oven temps are commonly about 93.33° C. (215° F.) or higher. If needed, various blowing agents activators can be incorporated into the composition to cause expansion at different temperatures outside the above ranges. Generally, prior art expandable foams have a range of expansion ranging from approximately 100 to over 1000 percent. The level of expansion of the material may be increased to as high as 1500 percent or more, but is typically between 0% and 300%. In general, higher expansion will produce materials with lower strength and stiffness properties.

It is also contemplated that the reinforcing material <b>14</b> could be delivered and placed into contact with the member through a variety of delivery systems which include, but are not limited to, a mechanical snap fit assembly, extrusion techniques commonly known in the art as well as a mini-applicator technique as in accordance with the teachings of commonly owned U.S. Pat. No. 5,358,397 (“Apparatus For Extruding Flowable Materials”), hereby expressly incorporated by reference. In another embodiment, the reinforcing material <b>14</b> is provided in an encapsulated or partially encapsulated form, which may comprise a pellet, which includes an expandable foamable material encapsulated or partially encapsulated in an adhesive shell, which could then be attached to the member in a desired configuration. An example of one such system is disclosed in commonly assigned U.S. Pat. No. 6,422,575 for an “Expandable Pre-Formed Plug” issued Jul. 23, 2002, hereby incorporated by reference. In addition, preformed patterns may also be employed such as those made by extruding a sheet (having a flat or contoured surface) and then die cut in accordance with a predetermined configuration.

The present invention is graphically represented in <figref idref="DRAWINGS">FIG. 1</figref> and includes of an automotive frame or rail energy management enhancement system <b>10</b> formed in accordance with the teachings of the present invention. The system <b>10</b> imparts an increased capability redirect applied loads and impact energies to a preferred portion of an automotive vehicle and, thus, may be used in a variety of applications and areas of an automotive or other moving vehicle, such as land, marine, rail, and aerospace vehicles. For instance, the energy management enhancement system <b>10</b> may be used to inhibit deformation and distortion to targeted portions of an automotive vehicle, including the frame, rail, door, or other structural members used in vehicles, in the event of an impact to the exterior of the vehicle by an outside body. The system <b>10</b> serves to target, tune, or manage energy for absorption and/or transfer to other portions of the vehicle. As shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, the present invention comprises at least one member <b>12</b> having an interior portion and an exterior portion capable of receiving and supporting a suitable amount of a reinforcing material <b>14</b> molded or bonded on its sides which can be placed, geometrically constrained, attached, or adhered to at least a portion of an automotive structural rail or frame <b>16</b> through an attachment means <b>18</b> used to place the member <b>12</b> within the rail or frame <b>16</b>. The attachment means <b>18</b> may consist of a self-interlocking assembly, gravity/geometrically constrained placement, adhesive, a molded in metal fastener assembly such as a clip, push pins or snaps, integrated molded fasteners such as a clip, push pins, or snaps as well as a snap-fit assembly which is well known in the art. As shown in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the attachment means <b>18</b> may consist of a clip. The automotive frame or rail <b>16</b> imparts structural integrity to the vehicle and may serve as the carrier of certain body panels of the automotive vehicle which may be viewable, and capable of receiving impact energy, from the exterior of the vehicle. By attaching the member <b>12</b> having the reinforcing material <b>14</b> to the frame or rail <b>16</b>, additional structural reinforcement is imparted to the targeted portion of the frame or rail <b>16</b> where the member <b>12</b> is attached.

The present invention serves to place this targeted reinforcement in selected areas of a frame or rail <b>16</b> and provides the capability to absorb, direct, or manage impact energy typically encountered during an impact event from an external source or body, such as that typically encountered during a frontal/offset impact or collision. It is contemplated that the member <b>12</b> and the reinforcing material <b>14</b>, after activation, create a composite structure whereby the overall system <b>10</b> strength and stiffness are greater than the sum of the individual components. In the event of an impact to the exterior of the vehicle, the impact energy is managed by either energy absorption/dissipation or targeted direction of the energy to specific areas of the vehicle.

The energy management features of the present invention utilizes targeted placement of a plurality of triggers <b>20</b> incorporated within the interior or inner portion of the member <b>12</b> or the exterior or outer portion of the member <b>12</b> along the frame or rail <b>16</b>, as shown in <figref idref="DRAWINGS">FIG. 1</figref>. The triggers <b>20</b> are targeted or otherwise tuned for placement along either or both of selected areas of the members <b>12</b> or, alternatively, the frame or rail <b>16</b> itself, to direct the placement of energy to targeted areas of the vehicle during an impact and initiate folds in the structure inducing axial collapse. As shown in <figref idref="DRAWINGS">FIGS. 2-6</figref>, the system <b>10</b> of the present invention can be integrated within vehicle cavities utilizing a plurality of members <b>12</b> in a variety of predetermined shapes, forms, and thicknesses corresponding to the size, shape, and form of the cavity of the specific automotive application selected for energy management without compromising the visual appearance, functionality, or aesthetic quality of the exterior portions and paintable surfaces of the vehicle. In a preferred embodiment, the trigger or plurality of triggers <b>20</b> are incorporated and integrated within an interior portion of the member <b>12</b> and designed as notches, holes, or any other step change in the geometry of the interior portion of the member. However, the present invention also contemplates the use of pre-formed triggers <b>20</b> in the rail <b>16</b> or along selected portions of either or both of the inner and outer portions of the member <b>12</b>. In some cases the triggers <b>20</b> may simply consist of a segment of the interior portion of the member that is specifically not coated with an expandable material as shown in <figref idref="DRAWINGS">FIG. 2</figref>. In other applications, a plurality of triggers <b>20</b> may be utilized such as a notch as shown in <figref idref="DRAWINGS">FIG. 1</figref> or a cut-out hole of a portion of both the inner and outer member <b>12</b>, as also shown in <figref idref="DRAWINGS">FIG. 1</figref>. As graphically shown in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, a trigger <b>20</b> of the present invention may also comprise a hole or other step change in the geometry of member <b>12</b> comprising a varying wall thickness of the trigger <b>20</b> with or without application if the reinforcing material <b>14</b>.

The reinforcing material <b>14</b> includes an impact energy absorbing, structural reinforcing material, which results in either a rigid or semi-rigid attachment to at least one member <b>12</b> having at least one trigger <b>20</b>. It is contemplated that the reinforcing material <b>14</b> could be applied to at least one member <b>12</b> in a variety of patterns, shapes, and thicknesses to accommodate the particular size, shape, and dimensions of the cavity to be filled by the reinforcing material <b>14</b> after activation. The placement of the member <b>12</b> along the selected frame or rail <b>16</b> as well as placement of the material <b>14</b> along the surfaces of the member <b>12</b> itself, and particularly either or both of the interior portion and exterior portion of the member <b>12</b>, can be applied in a variety of patterns and thicknesses to target or tune energy management enhancement or deformation reduction in selected areas of the vehicle where a reduction or redirection of impact energy would serve to limit damage to the vehicle passenger compartment and permit ingress and egress to the vehicle for passengers. The material <b>14</b> is activated through the application of heat typically encountered in an automotive e-coat oven or other heating operation in the space defined between the member <b>12</b>, now attached to the frame or rail <b>16</b> in either or pre-production facility or the final vehicle assembly operation. The resulting composite structure includes a wall structure formed by the rail or frame <b>16</b> joined to the at least one member <b>12</b> with the aid of the material <b>14</b>. It has been found that structural attachment through the use of the member <b>12</b> and the material <b>14</b> is best achieved when the material <b>14</b> is selected from materials such as those offered under product designations L-5204, L-5205, L-5206, L-5207, L-5208, L-5209, L-5214, and L-5222 sold by L&amp;L Products, Inc. of Romeo, Mich. For semi-structural attachment of the frame or rail <b>16</b> through the use of the member <b>12</b> and the material <b>14</b>, best results were achieved when the material <b>14</b> is selected from materials such as those offered under product designations L-4100, L-4200, L-4000, L-2100, L-1066, L-2106, and L-2108 sold by L&amp;L Products, Inc. of Romeo, Mich.

The properties of the reinforcing material <b>14</b> include structural foam characteristics, which are preferably heat-activated to expand and cure upon heating, typically accomplished by gas release foaming coupled with a cross-linking chemical reaction. The material <b>14</b> is generally applied to the member <b>12</b> in a solid or semi-solid state. The material <b>14</b> may be applied to the outer surface of the member <b>12</b> in a fluid state using commonly known manufacturing techniques, wherein the material <b>14</b> is heated to a temperature that permits the foamable material to flow slightly to aid in substrate wetting. Upon curing the material <b>14</b> hardens and adheres to the outer surface of the member <b>12</b>. Alternatively, the material <b>14</b> may be applied to the member <b>12</b> as precast pellets, which are heated slightly to permit the pellets to bond to the outer surface of the member <b>12</b>. At this stage, the material <b>14</b> is heated just enough to flow slightly, but not enough to cause the material <b>14</b> to thermally expand. Additionally, the material <b>14</b> may also be applied by heat bonding/thermoforming or by co-extrusion. Note that other stimuli activated materials capable of bonding can be used, such as, without limitation, an encapsulated mixture of materials that, when activated by temperature, pressure, chemically, or other by other ambient conditions, will become chemically active. To this end, one aspect of the present invention is to facilitate a streamlined manufacturing process whereby the material <b>14</b> can be placed along the member <b>12</b> in a desired configuration wherein the member <b>12</b> is then attached by the attachment means <b>18</b> or geometrically constrained to the frame or rail <b>16</b> without attachment means at a point before final assembly of the vehicle. As shown in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the attachment means <b>18</b> of the present invention may comprise a clip which is well known in the art. In this regard, the system <b>10</b> of the present invention provides at least one, but possibly a plurality of, members <b>12</b> which are placed along and attached to the selected frame or rail <b>16</b> such that adequate clearance remains for existing and necessary hardware that may be located inside a traditional automotive body cavity to provide window movement, door trim, etc. As shown in <figref idref="DRAWINGS">FIG. 7</figref>, the system <b>10</b> may also be used in hydroform applications wherein a plurality of interlocking members <b>12</b> are shaped for placement within a closed and then restrained by an attachment means <b>18</b> consisting of a self-interlocking retention piece. In the particular hydroform embodiment shown in <figref idref="DRAWINGS">FIG. 7</figref>, the trigger or triggers <b>20</b> of the present invention consists of a hole or deformation extending through the interior portion of the interlocking members <b>12</b> and may further comprise step change in the geometry of the wall thickness of the interlocking members <b>12</b>.

The energy management enhancement system <b>10</b> disclosed in the present invention may be used in a variety of applications where reinforcement is desired to transfer, direct, and/or absorb impact energy that may be applied to structural members of an automotive vehicle through an external source or collision to the vehicle. As shown in <figref idref="DRAWINGS">FIG. 8</figref> in a pre-impact state, the system <b>10</b> may be used to control and direct energy management in frontal impact testing of automotive vehicles through targeted bending, buckling, and collapsing of the system in a progressive manner while still providing some reinforcement stability in the bending process resulting in the system shown in a post-impact state in <figref idref="DRAWINGS">FIG. 9</figref>. Namely, as shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref>, axial collapse may be created by opposing or dual bending modes through the use of a plurality of triggers <b>20</b>. The system <b>10</b> has particular application in automotive frame or rail applications where the overall weight of the structure being reinforced is a critical factor and there is a need for reinforcement and/or inhibition of deformation and distortion resulting from an impact to the vehicle. For instance, the system <b>10</b> may be used to reduce or inhibit structural distortion of portions of automotive vehicles, aircraft, marine vehicles, building structures or other similar objects that may be subject to an impact or other applied structural force through either natural or man-made means. In the embodiment disclosed, the system <b>10</b> is used as part of an automobile frame or rail assembly to inhibit distortion of selected areas of an automobile through the transfer and/or absorption of applied energy, and may also be utilized in conjunction with rockers, cross-members, chassis engine cradles, roof systems, roof bows, lift gates, roof headers, roof rails, fender assemblies, pillar assemblies, radiator/rad supports, bumpers, body panels such as hoods, trunks, hatches, cargo doors, front end structures, and door impact bars in automotive vehicles as well as other portions of an automotive vehicle which may be adjacent to the exterior of the vehicle. The skilled artisan will appreciate that the system may be employed in combination with or as a component of a conventional sound blocking baffle, or a vehicle structural reinforcement system, such as is disclosed in commonly owned co-pending U.S. application Ser. No. 09/524,961 and U.S. Pat. No. 6,467,834, both of which are hereby incorporated by reference.

The preferred embodiment of the present invention has been disclosed. A person of ordinary skill in the art would realize however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.