# Patent

## Title
Elastically deformable energy management assembly and method of managing energy absorption

## Abstract

An elastically deformable energy management assembly includes a first component. Also included is at least one protrusion extending from the first component, the at least one protrusion having an outer surface. Further included is a second component comprising at least one aperture defined by an aperture wall, the aperture wall in slideable engagement with the outer surface of the at least one protrusion, wherein at least one of the protrusion and the aperture wall comprises an elastically deformable material.

## Background
FIELD OF THE INVENTION
The invention relates to energy management arrangements for managing energy absorption in response to a load and, more particularly, to an elastically deformable energy management assembly, as well as a method of managing energy absorption with the elastically deformable energy management assembly.
BACKGROUND
Efforts to manage or absorb energy are widespread in numerous industries. A vehicle zone is an example of an application in which energy absorption is emphasized. Currently, components may be disposed in close proximity with an energy absorbing component in an attempt to absorb energy. The components may be mated to each other in a manufacturing process and are subject to positional variation based on the mating arrangements between the components. The arrangement may include components mutually located with respect to each other by 2-way and/or 4-way male alignment features; typically undersized structures which are received into corresponding oversized female alignment features such as apertures in the form of openings and/or slots. There may be a clearance between at least a portion of the alignment features which is predetermined to match anticipated size and positional variation tolerances of the mating features as a result of manufacturing (or fabrication) variances. As a result, poor fit may occur, thereby leading to less efficient energy absorption upon being impacted by an object.
SUMMARY OF THE INVENTION
In one exemplary embodiment, an elastically deformable energy management assembly includes a first component. Also included is at least one protrusion extending from the first component, the at least one protrusion having an outer surface. Further included is a second component comprising at least one aperture defined by an aperture wall, the aperture wall in slideable engagement with the outer surface of the at least one protrusion, wherein at least one of the protrusion and the aperture wall comprises an elastically deformable material.
In another exemplary embodiment, a method of managing energy absorption with an elastically deformable energy management assembly is provided. The method includes engaging an outer surface of a protrusion of a first component with an aperture wall of a second component, the protrusion disposed within an aperture defined by the aperture wall. The method also includes elastically deforming at least one of the aperture wall and the protrusion upon engagement with the second component. The method further includes transferring energy between the protrusion and the aperture wall during imposition of a load condition on the elastically deformable energy management assembly.
In yet another exemplary embodiment, an energy management assembly for a vehicle zone includes a potential contact zone component. Also included is at least one protrusion extending from the potential contact zone component, the at least one protrusion having an outer surface. Further included is a mated component comprising at least one aperture defined by an aperture wall, the aperture wall in slideable engagement with the outer surface of the at least one protrusion, wherein at least one of the protrusion and the aperture wall comprises an elastically deformable material.
The above features and advantages and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
Other features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which:
FIG. 1 is a side, elevational schematic view of an elastically deformable energy management assembly;
FIG. 2 is a schematic view of an aperture and protrusion arrangement of the elastically deformable energy management assembly;
FIG. 3 is a side, elevational schematic view of the elastically deformable energy management assembly in a first position according to another aspect of the invention;
FIG. 4 is a side elevational schematic view of the elastically deformable energy management assembly in a second position according to another aspect of the invention; and
FIG. 5 is a flow diagram illustrating a method of managing energy absorption with the elastically deformable energy management assembly.



DESCRIPTION OF THE EMBODIMENTS
Referring to FIG. 1, illustrated is an elastically deformable energy management assembly 10. The elastically deformable energy management assembly 10 comprises matable components, such as a first component 12 and a second component 14 that may be disposed in a mated configuration with respect to each other. In one embodiment, the elastically deformable energy management assembly 10 is employed in a vehicle application, however, it is to be understood that the components may be associated with numerous other applications and industries that benefit from energy management, such as home appliance and aerospace applications, for example. In an exemplary embodiment, energy management refers to absorption of energy in response to a load or contact, directly or indirectly, on the second component 14. In a vehicle application, the elastically deformable energy management assembly 10 may be disposed proximate a potential contact zone to absorb energy. A contact zone may refer to any location that is susceptible to being contacted by an object, such as areas proximate an occupant's knees or head, for example. However, it is to be appreciated that a contact zone does not require occupant contact, as contact may occur between vehicle components.
The elastically deformable energy management assembly 10 is illustrated in distinct conditions which will be described in detail below. In the illustrated embodiment, the first component 12 comprises a main portion 16 that includes a first surface 18. Extending from the main portion 16, and more specifically from the first surface 18, is a protrusion 20. The protrusion 20 may be formed in numerous alternate geometries, such as in the illustrated substantially circular geometry. In one embodiment, the protrusion 20 comprises a tubular member that includes a hollow portion, which increases the deformability of the protrusion 20, the deformability of which is described in greater detail below. Irrespective of the precise geometry, the protrusion 20 includes an outer surface 22 (FIG. 2) that forms a perimeter and a protrusion diameter in the case of a circular protrusion.
The second component 14 is configured to engage in a tight, mated relationship with the protrusion 20 of the first component 12. To ensure a fitted engagement between the second component 14 and the outer surface 22 of the protrusion 20, the protrusion 20 is disposed within an aperture 24 defined by an aperture wall 26 of the second component 14. The aperture 24 defined by the aperture wall 26 may be a molded-in feature of the second component 14 or may be a bracket configured to be inserted into and secured to the second component 14. The aperture wall 26 comprises an aperture width or perimeter that is smaller than the respective perimeter or diameter of the protrusion 20. The aperture 24 extends through the second component 14 and may be referred to herein as a slot. The tight, mated arrangement of the first component 12 and the second component 14 is facilitated by the elastically deformable nature of either or both of the protrusion 20 and the aperture wall 26, which accounts for positional variation of the components that is inherently present due to manufacturing processes.
Referring to FIG. 2, in conjunction with FIG. 1, the protrusion 20 and the aperture 24 are shown in various positions. As shown, the aperture wall 26 may be shaped to include a detent region 28 configured to facilitate initial insertion and retaining of the protrusion 20. In one embodiment, the detent region 28 may be disposed proximate a central or mid-portion of the aperture 24, with respect to a longitudinal direction 30 of the aperture 24. The protrusion 20 and the aperture 24 are configured to move relative to each other. In one embodiment, the first component 12, and therefore the protrusion 20, is fixed in a stationary position, with the second component 14 configured to move relative to the first component 12 upon the imposition of a load on the second component 14. The relative movement of the first component 12 may be translation, rotation, or a combination thereof. It is also contemplated that the first component 12 is moveable.
The elastically deformable material of the protrusion 20 and/or the aperture wall 26 provides malleability of the protrusion 20 and/or aperture wall 26, thereby allowing the protrusion 20 to slide relative to the aperture wall 26 of the second component 14. In this way, the second component 14 is in slideable engagement with the outer surface 22 of the protrusion 20. Specifically, the second component 14, and more particularly the aperture wall 26, remains in constant, tight contact with the outer surface 22 of the protrusion 20 during relative translation between the first component 12 and the second component 14. Additionally, the deformable nature of the material(s) that are in contact provides an energy absorptive quality to the elastically deformable energy management assembly 10.
In operation, the second component 14 is configured to translate upon application of a force (e.g., contact of an object). In one embodiment, the load is introduced proximate a load surface 32. As one can appreciate, in some embodiments, the load proximate to the surface 32 would only be a vector of the total load. This may be advantageously achieved based on the rotational aspect of the second component 14, as opposed to straight translation, as described in detail below. Energy associated with the contact is transferred to, and absorbed by, the first component 12, and more particularly the protrusion 20, that is in contact with the aperture wall 26. As the second component 14 moves from a first position 40 to a second position 42, the aperture 24 moves relative to the protrusion 20, thereby resulting in relative displacement of the protrusion 20 within the aperture 24. It is to be appreciated that the distance displaced by the aperture 24 relative to the protrusion 20 will vary and is determined by the force applied on the load surface 32 of the second component 14.
Referring to FIGS. 3 and 4, illustrated is an alternative embodiment of the elastically deformable energy management assembly 10. The embodiment is similar in many respects to the embodiments described in detail above, such that duplicative description of several features of the elastically deformable energy management assembly 10 is not necessary. Additionally, similar reference numerals are employed, where applicable. The alternative embodiment depicts a pivot element 50 disposed proximate a rear surface 52 of the second component 14. The pivot element 50 is operatively coupled to the second component 14 and is configured to facilitate rotation of the second component 14. It is to be appreciated that the pivot element 50 comprises a fastener, a snap-in feature, or the like, and may comprise a flexible or elastically deformable material. It is further contemplated that the pivot element 50 may be a rigid fastener retained by a retainer 54 that is configured to flexibly provide torsional movement, thereby facilitating rotation of the second component 14.
As shown, the rotational aspect of the second component 14 induces relative movement between the protrusion 20 and the aperture wall 26, similar to that described above with respect to previously described embodiments. The second component 14 is shown in a first position 60 (FIG. 3) and a second position 62 (FIG. 4).
Any suitable elastically deformable material may be used for the protrusion 20 and/or the aperture wall 26. The term “elastically deformable” refers to components, or portions of components, including component features, comprising materials having a generally elastic deformation characteristic, wherein the material is configured to undergo a resiliently reversible change in its shape, size, or both, in response to application of a force. The force causing the resiliently reversible or elastic deformation of the material may include a tensile, compressive, shear, bending or torsional force, or various combinations of these forces. The elastically deformable materials may exhibit linear elastic deformation, for example that described according to Hooke's law, or non-linear elastic deformation.
Numerous examples of materials that may at least partially form the components include various metals, polymers, ceramics, inorganic materials or glasses, or composites of any of the aforementioned materials, or any other combinations thereof. Many composite materials are envisioned, including various filled polymers, including glass, ceramic, metal and inorganic material filled polymers, particularly glass, metal, ceramic, inorganic or carbon fiber filled polymers. Any suitable filler morphology may be employed, including all shapes and sizes of particulates or fibers. More particularly any suitable type of fiber may be used, including continuous and discontinuous fibers, woven and unwoven cloths, felts or tows, or a combination thereof. Any suitable metal may be used, including various grades and alloys of steel, cast iron, aluminum, magnesium or titanium, or composites thereof, or any other combinations thereof. Polymers may include both thermoplastic polymers or thermoset polymers, or composites thereof, or any other combinations thereof, including a wide variety of co-polymers and polymer blends. In one embodiment, a preferred plastic material is one having elastic properties so as to deform elastically without fracture, as for example, a material comprising an acrylonitrile butadiene styrene (ABS) polymer, and more particularly a polycarbonate ABS polymer blend (PC/ABS), such as an ABS acrylic. The material may be in any form and formed or manufactured by any suitable process, including stamped or formed metal, composite or other sheets, forgings, extruded parts, pressed parts, castings, or molded parts and the like, to include the deformable features described herein. The material, or materials, may be selected to provide a predetermined elastic response characteristic of the protrusion 20 and/or the aperture wall 26. The predetermined elastic response characteristic may include, for example, a predetermined elastic modulus.
Each of the embodiments described above may include elastic deformation of the protrusion 20 and/or the aperture wall 26. The elastic deformation occurs predominantly proximate a location of engagement between the outer surface 22 of the protrusion 20 and the aperture wall 26 of the second component 14. This elastic deformation may be elastically averaged to account for any positional errors of the first component 12 and the second component 14. In other words, gaps and/or misalignment that would otherwise be present due to positional errors associated with portions or segments of the first component 12 and the second component 14, particularly locating and retaining features. Specifically, the positional variance of regions of the portion engaged with the aperture wall 26 is offset by the remainder of the engagement portion. In other words, the deformation along the outer surface 22 and/or the aperture wall 26 is averaged in aggregate.
Elastic averaging provides elastic deformation of the interface(s) between mated components, wherein the average deformation provides a precise alignment, the manufacturing positional variance being minimized to Xmin, defined by Xmin=X/√N, wherein X is the manufacturing positional variance of the locating features of the mated components and N is the number of features inserted. To obtain elastic averaging, an elastically deformable component is configured to have at least one feature and its contact surface(s) that is over-constrained and provides an interference fit with a mating feature of another component and its contact surface(s). The over-constrained condition and interference fit resiliently reversibly (elastically) deforms at least one of the at least one feature or the mating feature, or both features. The resiliently reversible nature of these features of the components allows repeatable insertion and withdrawal of the components that facilitates their assembly and disassembly. Positional variance of the components may result in varying forces being applied over regions of the contact surfaces that are over-constrained and engaged during insertion of the component in an interference condition. It is to be appreciated that a single inserted component may be elastically averaged with respect to a length of the perimeter of the component. The principles of elastic averaging are described in detail in commonly owned, co-pending U.S. patent application Ser. No. 13/187,675, the disclosure of which is incorporated by reference herein in its entirety. The embodiments disclosed above provide the ability to convert an existing component that is not compatible with the above-described elastic averaging principles to an assembly that does facilitate elastic averaging and the benefits associated therewith.
In one embodiment the elastically deformable energy management assembly 10 includes a plurality of protrusions configured to engage a plurality of apertures defined by a plurality of aperture walls. In such an embodiment, the elastic deformation of each of the plurality of protrusions and/or the plurality of aperture walls is averaged in aggregate relative to each other, in accordance with the principles referenced above.
A method of managing energy absorption 100 is also provided, as illustrated in FIG. 5, and with reference to FIGS. 1-4. The elastically deformable energy management assembly 10, and more specifically the elastically deformable nature of the protrusion 20 and/or the aperture wall 26, has been previously described and specific structural components need not be described in further detail. The method 100 includes engaging 102 the outer surface 22 of the protrusion 20 with the aperture wall 26 of the second component 14, the protrusion 20 disposed within the aperture 24 defined by the aperture wall 26. At least one of the aperture wall 26 and the protrusion 20 is elastically deformed 104 upon engagement. The method also includes transferring energy 106 between the protrusion 20 and the aperture wall 26 during imposition of a load condition on the elastically deformable energy management assembly 10.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the application.

## Claims

1. An elastically deformable energy management assembly comprising:
a first component;
at least one protrusion extending from the first component in a first direction, the at least one protrusion having an outer surface, the protrusion formed of an elastically deformable material;
a second component comprising at least one aperture defined by an aperture wall, the aperture wall in slideable engagement with the outer surface of the at least one protrusion, the aperture comprising a slot having a first closed end and a second closed end, the protrusion slideable within the slot in a direction perpendicular to the first direction of the at least one protrusion; and
a detent of the slot configured to retain the protrusion in an unloaded condition up to a predetermined force, the detent having a width greater than the width of the remainder of the slot, the protrusion moveable into the remainder of the slot upon application of a force in excess of the predetermined force.

2. The elastically deformable energy management assembly of claim 1, wherein the detent is disposed proximate a mid-portion along a longitudinal direction of the slot.

3. The elastically deformable energy management assembly of claim 1, wherein the slot is molded into the second component.

4. The elastically deformable energy management assembly of claim 1, wherein the slot is formed in a bracket insertable into the second component.

5. The elastically deformable energy management assembly of claim 1, wherein the first component is disposed in a fixed, stationary position, wherein the second component is moveable relative to the first component.

6. The elastically deformable energy management assembly of claim 5, wherein the second component is rotatable relative to the first component.

7. The elastically deformable energy management assembly of claim 6, further comprising a pivot element operatively coupled to the second component.

8. The elastically deformable energy management assembly of claim 1, wherein the second component remains in a contact interference condition with the outer surface of the protrusion over a range of positions of the second component.

9. The elastically deformable energy management assembly of claim 1, further comprising a plurality of protrusions of the first component disposed within a plurality of apertures of the second component.

10. The elastically deformable energy management assembly of claim 9, wherein an amount of deformation of each of the plurality of protrusions is averaged in aggregate.

11. The elastically deformable energy management assembly of claim 1, wherein the elastically deformable energy management assembly is disposed in a vehicle.

12. A method of managing energy absorption with an elastically deformable energy management assembly comprising:
engaging an outer surface of a protrusion of a first component with an aperture wall of a second component upon insertion of the protrusion in a first direction into an aperture defined by the aperture wall, the aperture comprising a slot and the protrusion slideable within the slot in a direction perpendicular to the first direction;
elastically deforming the protrusion upon engagement with the second component;
retaining the protrusion within a detent of the slot in an unloaded condition, the detent having a width greater than the width of the remainder of the slot; and
transferring energy between the protrusion and the aperture wall during imposition of a load condition on the elastically deformable energy management assembly.

13. The method of claim 12, further comprising engaging a plurality of protrusions with a plurality of aperture walls and elastically deforming the plurality of protrusions, wherein the plurality of protrusions comprises an elastically deformable material.

14. The method of claim 13, further comprising performing an elastic averaging of the amount of deformation of each of the plurality of protrusions.

15. The method of claim 12, further comprising engaging a plurality of protrusions with a plurality of aperture walls and elastically deforming the plurality of aperture walls, wherein the plurality of aperture walls comprises an elastically deformable material.

16. The method of claim 15, further comprising performing an elastic averaging of the amount of deformation of each of the plurality of aperture walls.

17. An energy management assembly for a vehicle zone comprising:
a potential contact zone component;
at least one protrusion extending from the potential contact zone component in a first direction, the at least one protrusion having an outer surface, the protrusion formed of an elastically deformable material; and
a mated component comprising at least one aperture defined by an aperture wall, the aperture wall in slideable engagement with the outer surface of the at least one protrusion, the aperture comprising a slot having a first closed end and a second closed end, the protrusion slideable within the slot in a direction perpendicular to the first direction of the at least one protrusion; and
a detent of the slot configured to retain the protrusion in an unloaded condition up to a predetermined force, the detent having a width greater than the width of the remainder of the slot, the protrusion moveable into the remainder of the slot upon application of a force in excess of the predetermined force.

18. The energy management assembly of claim 17, wherein the potential contact zone component is disposed in a vehicle interior.