Energy absorber with double-acting crush lobes

• US 8,602,183 B2
• Filed: 06/24/2010
• Issued: 12/10/2013
• Est. Priority Date: 06/24/2009
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated), Shape
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated), Shape
• Inventors: VandenBerge, Thomas C., Wilde, Scott D., Cormier, Joel M., Mills, Geoffrey A., Zecchin, David
• Primary Examiner(s): IRVIN, THOMAS W
• Application Number:
  US12/822,310
• Publication Number:
  US 20100326782A1
• Time in Patent Office: 1,265 Days
• Field of Search: 188/371, 188/372, 188/377, 296/187.03, 296/187.05, 296/187.06, 296/187.09, 267/64.27
• US Class Current: 188/377
• CPC Class Codes: B60R 2021/0273 automatically movable to an operative position, e.g. in case of collision or impending collision
• CPC Class Codes: B60R 21/02 Occupant safety arrangements or fittings , e.g. crash pads seat belts with crash pads B60R22/14; removable children's seats having a front guard or barrier B60N2/2839
• CPC Class Codes: B60R 21/38 using means for lifting bonnets
• CPC Class Codes: F16F 7/128 characterised by the members, e.g. a flat strap, yielding through stretching, pulling apart

Abstract

An energy absorber includes opposing aligned crush lobes expandable in opposite directions, and when expanded, potentially collapse with different energy-absorbing rates and stroke distances. The energy absorber forms a subassembly design that is adaptable and easily modified for predetermined energy absorption crush curves and specific energy-absorbing circumstances, such that it can be used inside a vehicle passenger compartment or outside a vehicle in different locations, such as for a knee bolster on the instrument panel, or on a door inner panel, or on an under-knee seat component, or on a headliner or A-pillar cover, or hood-lifter for pedestrian safety. One version of the energy absorber includes formed sheets bonded along a perimeter to define two cavities and an inflator-holding pocket connected to the cavities by integrally-formed tunnels.

Claims

1. An energy absorber construction comprising:

first and second separately-formed polymeric panel members with opposing walls connected together, the opposing walls having inner and outer stiff wall sections that extend generally parallel a direction of expansion and that are sufficiently stiff to maintain their shape before and during expansion and also to absorb energy during an impact stroke, the opposing walls each defining at least one pair of crush lobes that define at least one cavity therebetween, with each crush lobe being movable between a collapsed position where the crush lobes are collapsed toward each other with the opposing walls at least partially interfitting and having adjacent interior cavities that combine to define an open space between the opposing walls with the opposing walls being adapted to undergo expansion without kinking, and an expanded position where the crush lobes are expanded in generally opposite directions; and

a gas-producing inflator connected to the cavity and constructed to expand the crush lobes prior to an impact.

2. The construction defined in claim 1, wherein the first and second panel members are molded separately and are attached by one of mechanically attached, adhesively bonded, thermally bonded, or welded.

3. The construction defined in claim 1, wherein the first and second panel members are molded simultaneously by one of blow molding or injection molding.

4. The construction defined in claim 1, wherein the inflator provides gas for expanding the at least one pair of crush lobes from the retracted position to the expanded position, whereby each of the at least one pair of crush lobes provide a shorter crush stroke when in the retracted position and a longer crush stroke when in the expanded position.

5. The construction defined in claim 1, wherein the at least one pair of crush lobes are constructed to expand sequentially.

6. The construction defined in claim 1, wherein the at least one pair of crush lobes are constructed to expand simultaneously.

7. The construction defined in claim 1, wherein, upon impact, the at least one pair of crush lobes collapse simultaneously.

8. The construction defined in claim 1, wherein the at least one pair of crush lobes each provide a different level of energy absorption.

9. The construction defined in claim 1, wherein the at least one pair of crush lobes include an offset in their sidewalls constructed to unroll during extension and to roll to absorb added energy during an impact.

10. The construction defined in claim 1, wherein at least one of the panel members includes a mechanical fuse that controls exhaust of fluid from the cavity during an impact.

11. The construction defined in claim 1, wherein the inflator comprises one of a container of gas or container holding a gas generating substance.

12. The construction defined in claim 1, wherein the first and second panel members are thermoformed members.

13. The construction defined in claim 1, wherein the at least one pair of crush lobes include first and second crush lobes that are aligned, with one of the first and second crush lobes being larger than the other, and at least one of the first and second crush lobes including material extending nested into the other crush lobe when in the collapsed position.

14. The construction defined in claim 1, wherein the at least one pair of crush lobes include first and second pairs of crush lobes on right-hand and left-hand sides of the panel members.

15. The construction defined in claim 1, wherein the at least one pair of crush lobe includes first and second crush lobes on each of the first and second panel members and also an air feed tunnel defined therebetween.

16. The construction defined in claim 1, wherein the inflator is positioned between the panel members.

17. The construction defined in claim 1, wherein the at least one pair of crush lobes include first and second crush lobes that define a first dimension when in the collapsed position and a second dimension at least twice the first dimension when in the expanded position.

18. The construction defined in claim 17, wherein the second dimension is at least four times the first dimension when in the expanded position.

19. The construction defined in claim 1, wherein the inflator comprises a micro gas generator.

20. The construction defined in claim 1, wherein the inflator comprises a micro gas generator, and wherein the micro gas generator includes a diffuser.

21. An energy absorber construction comprising:

first and second separately-formed panel members with opposing walls, the opposing walls having inner and outer stiff wall sections that extend generally parallel a direction of expansion and that are sufficiently stiff to maintain their shape before and during expansion and also to absorb energy upon impact, the panels members being attached together, the opposing walls defining at least one set of aligned crush lobes extending in opposite directions and defining a sealed cavity therebetween and that are each movable between a collapsed position where the crush lobes are collapsed toward each other with the opposing walls at least partially interfitting and having adjacent interior cavities that combine to define an open space between the opposing walls, and an expanded position where the crush lobes are expanded in opposite directions, at least one of the crush lobes including sidewalls having an offset ring section defining an S-shaped cross section with arcuate portions forming opposing concavities such that the offset ring section does not include wall sections folded flat against each other, the offset ring section being adapted to unroll when the crush lobe is expanded and later roll and collapse when the crush lobe is compressed from the expanded position toward the retracted position;

whereby, when the crush lobes are in the expanded position and the construction is impacted, energy is absorbed both by the offset ring section of the sidewalls rolling and also by compressed fluid in the sealed cavity.

22. The construction defined in claim 21, including an inflator connected to the cavity of the crush lobes and constructed to expand the crush lobes.

23. The construction defined in claim 21, including a mechanical fuse in one of the panel members constructed to provide an escape outlet for pressurized gas in the cavity.

24. The construction defined in claim 21, wherein the opposing walls include at least one attachment flange for securing the construction to a support.

25. An energy absorber construction comprising:

a two-direction expandable energy absorber including opposing walls of preformed polymeric material forming crush lobes sealed together to define at least two cavities and a passage connecting a center region to the two cavities, the opposing walls each including at least one of the crush lobes with the crush lobe being configured to move from an outward expanded position toward a collapsed retracted position during an impact, the opposing walls each having shallow channels combining to form the passage and also having deflector walls on one edge of the center region, and the opposing walls including inner and outer stiff wall sections that are spaced apart and extend generally parallel a direction of expansion and that maintain their shape during expansion; and

an inflator located in the center region and mounted to the center region and connected to the passage at a second edge of the center region opposite the deflector walls, with the deflector walls being configured to split and direct inflator gases from the center region toward the two cavities for expanding the crush lobes from the retracted position to the expanded position.

26. The construction defined in claim 25, wherein the inflator includes a fast acting gas generating material.

27. The construction defined in claim 25, wherein the crush lobes of each panel member are aligned with another one of the crush lobes.

28. The construction defined in claim 27, wherein the aligned crush lobes interfit at least partially into each other.

29. The construction defined in claim 25, including a cover attached to one of the crush lobes having an aesthetic first surface for covering the assembly.

30. The construction defined in claim 29, wherein the support member includes a mounting bracket adapted to be attached under an instrument panel and which positions the construction to engage the passenger'"'"'s knees during a vehicle impact.

31. The construction defined in claim 29, wherein the crush lobes each include a cross section with a sidewall defining at least one offset ring section with a first radii that is between about 1 and 10 mm and wall thickness between about 0.5 and 5 mm so that upon rapid movement from the retracted position to the expanded position, a stiff portion of the sidewalls causes the offset ring section to unroll without kinking, but during movement from the expanded position to the retracted position causes the offset ring section to roll in a manner absorbing energy.

32. The construction defined in claim 31, wherein the ring sections are non-circular and elongated.

33. An energy absorber construction comprising:

an energy absorber having adjacent panels forming at least one pair of aligned crush lobes configured to move between a collapsed position adjacent each other and an extended position away from each other, the crush lobes each including an outer wall section extending from the associated panel, an intermediate wall section extending from the outer wall section, the intermediate wall section defining an S-shaped cross section having arcuate portions forming opposing concavities such that the intermediate wall section does not include wall sections folded flat against each other, the arcuate portions defining first and second radii of between about 1-10 mm to provide rolling material movement during expansion and contraction of the crush lobes, and an inner wall section extending from the intermediate wall section, the intermediate wall section being a thinner thickness than the inner and outer wall sections and being more flexible than the inner and outer wall sections and also the inner and outer wall sections being sufficiently stiff to maintain their shape during expansion and being spaced from the intermediate wall section, so that during extension from the collapsed position to the extended position, ends of the intermediate wall section roll into general alignment with the inner and outer wall sections, and during collapse from the extended position toward the collapsed position, the ends of the intermediate wall section roll toward and re-align with the intermediate wall section; and

a gas-generating inflator connected to the energy absorber to cause extension of the crush lobes from the collapsed position to the extended position.

34. A method comprising steps of:

forming two panels each with at least one crush lobe therein configured to absorb energy during an impact, each crush lobe having inner and outer wall sections of at least 1 mm thickness and extending in a direction of expansion and stiff enough to maintain a shape when the at least one crush lobe is expanded and to cause an intermediate wall section to roll when impacted, the crush lobes of the two panels when mated having a total thickness dimension of at least 15 mm;

attaching the two panels together with the at least one crush lobes aligned to define a sealed cavity and facing in opposite directions, but with the crush lobes in a collapsed position with portions of opposing walls of the crush lobes interfitting and combining to define a continuous open space between the opposing walls; and

connecting a gas-generating inflator to the cavity to extend the crush lobes to an extended position.

35. The method defined in claim 34, wherein, prior to an impact which will crush the crush lobes from the extended position toward the collapsed position, operating the inflator to move the crush lobes to the extended position.

36. The method defined in claim 34, including steps of extending the crush lobes simultaneously from the collapsed position to the extended position.

37. A method comprising steps of:

providing first and second preformed separately-formed polymeric panel members with opposing walls, the opposing walls each having crush lobes defining two spaced-apart cavities with a center region therebetween, at least one of the first and second polymeric panel members having structure forming a preformed permanently-formed passage connecting the two cavities through the center region and forming a deflector wall along one edge of the center region for directing inflation gas from the center region toward the crush lobes, the crush lobes each including inner and outer stiff wall sections that extend generally parallel a direction of expansion and that are sufficiently stiff to maintain their shape during expansion;

attaching the panels members together with the crush lobes aligned, with each crush lobe being movable between a collapsed position where the crush lobes are collapsed toward each other and an expanded position where the crush lobes are expanded in generally opposite directions; and

attaching a gas-generating inflator to a second edge of the center region with the inflator operably connected to the passage and hence to the cavities, and with the crush lobes in the collapsed position, and thereafter expanding the crush lobes immediately prior to or during an impact by generating the gas with the inflator and flowing the gas from the inflator through the passage against the deflector wall and then toward the crush lobes to provide an energy absorbing device.

38. A method comprising steps of:

providing first and second separately-formed panel members with opposing walls attached together, the opposing walls defining at least one set of aligned crush lobes that interfit and that extend in opposite directions, the aligned crush lobes defining a sealed cavity therebetween and each being movable between a collapsed position where the crush lobes are collapsed toward each other and an expanded position where the crush lobes are expanded in opposite directions, at least one of the crush lobes including inner and outer stiff wall sections extending in a direction of expansion and spaced apart and being sufficiently stiff to maintain their shape during expansion, the intermediate wall section having an offset ring section defining an S-shaped cross section having arcuate portions forming opposing concavities such that the offset ring section does not include wall sections folded flat against each other, the arcuate portions when in the collapsed position each defining first and second radii of between about 1-10 mm to provide rolling material movement during expansion and contraction of the crush lobes with the arcuate portions being a thinner wall thickness than other parts of the S-shaped cross section such that the arcuate portions are more flexible; and

expanding the crush lobes from the collapsed position toward the expanded position including unrolling the offset ring section to substantially eliminate the S-shaped cross section when the crush lobes are expanded and later re-rolling the offset ring section when the crush lobes are compressed during an impact from the expanded position toward the retracted position;

whereby, when the crush lobes are in the expanded position and the construction is impacted, energy is absorbed both by the offset ring section of the sidewalls rolling and also by compressed fluid in the sealed cavity.

39. A method comprising steps of:

separately pre-forming two panels of polymeric material, each having walls with a thickness of at least 1 mm and having a non-uniform thickness, the walls having inner and outer wall sections extending in a direction of expansion that are sufficiently stiff to cause a radiused portion of each wall to roll and not kink when expanded and collapsed, each of the panels having at least one extendable crush lobe therein formed in part by the inner and outer wall sections and configured for compact storage but extendable prior to impact to absorb energy during an impact; and

attaching the two panels together with the at least one crush lobe of each of the two panels being aligned to define a sealed cavity and facing in opposite directions, the at least one crush lobe of each of the two panels being expandable, but when in a collapsed position having portions of opposing walls of the at least one crush lobe of each of the two panels interfitting and having internal cavities that combine to define a continuous open space between the opposing walls.