Bumper energy absorber with foam and non-foam pieces

Abstract

A bumper system includes a bumper beam having a face and ends, and an energy absorber mounted on the face. The energy absorber has a foam piece engaging the face and an injection-molded end piece securely attached to each end of the foam piece and also engaging the face. By this arrangement, the energy absorber is a single unit that can be handled and attached to the bumper beam, and also can include different end pieces while still using the same foam piece. In one form, the energy absorber also includes a center injection-molded piece and, in another form, includes a long injection-molded piece having foam sections molded onto it.

Description

BACKGROUND

The present invention relates to vehicle bumper systems having an energy absorber on a bumper beam, and more particularly relates to a bumper system having an energy absorber on the beam that is adapted to provide different levels of energy absorption in selected areas but further adapted to take maximum advantage of mass production.

Vehicle bumper systems often include a bumper beam for strength and a mounted energy absorber to help absorb energy and distribute stress across the bumper beam during impact. However, each different model vehicle requires a slightly different shape or different energy absorption profile, such that each different model vehicle requires a different mold for the energy absorber. Each additional mold is expensive, because they are relatively large and long. Further, it takes time and labor to change molds, and requires downtime of the molding machine.

Accordingly, a bumper system is desired that includes an energy absorber solving the aforementioned problems and having the aforementioned advantages.

SUMMARY OF THE PRESENT INVENTION

In one aspect of the present invention, a bumper system includes a bumper beam having a face and ends, and an energy absorber mounted on the face. The energy absorber has a foam piece engaging the face and an injection-molded end piece securely attached to an end of the foam piece and also engaging the face.

In another aspect of the present invention, a bumper system includes a bumper beam having a face and ends, and an energy absorber mounted on the face. The energy absorber has at least one foam piece engaging the face and at least one non-foam plastic piece securely attached to an end of the foam piece and also engaging the face. The foam piece and the non-foam piece form a single member that can be handled and attached as a unit to the bumper beam.

In another aspect of the present invention, a method comprises steps of molding a non-foam plastic component. The method further includes molding a foam component and attaching the non-foam plastic component to the foam component to form a unitary member that can be handled as a unit. The method still further includes engaging the unitary member against a face of a bumper beam.

In another aspect of the present invention, a bumper system includes a bumper beam having a face surface, and an energy absorber engaging the face surface. The energy absorber has an elongated non-foam injection-molded component with at least three longitudinally-spaced enlarged sections and further has a plurality of foam sections attached to the molded components between the enlarged sections.

These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a fragmentary perspective view of a bumper system including a bumper beam and a face-mounted energy absorber;

FIGS. 2-3 are cross sections taken along the lines II—II and III—III in FIG. 1 ;

FIG. 4 is a front perspective view of a second bumper system including a bumper beam and a modified face-mounted energy absorber;

FIG. 5 is a rear perspective view of the energy absorber shown in FIG. 4 ;

FIG. 6 is a top view of FIG. 4 ;

FIG. 7 is a rear view of FIG. 5 ;

FIGS. 8-9 are front and top views of a third bumper system;

FIGS. 10-11 are front and rear perspective view of the energy absorber shown in FIG. 8 ; and

FIG. 12 is a front perspective view of an injection molded solid plastic component of the energy absorber shown in FIGS. 10 — 11 .

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A bumper system 8 ( FIG. 1 ) includes a bumper beam 16 having a face and ends, and an energy absorber 10 mounted on the face. The energy absorber has a center-located foam piece 11 engaging the face and an injection-molded end piece 12 securely attached to each end of the foam piece and also engaging the face. By this arrangement, the energy absorber is a single unit that can be handled and attached to the bumper beam, and also the energy absorber can include different end pieces while still using the same foam piece.

More specifically, the energy absorber 10 is adapted to advantageously use a common center piece 11 made of foam, and any one of a variety of different injection-molded end pieces attached to the foam. The illustrated end piece 12 includes loops or attachment flanges 13 and is insert-molded onto an end of the foam piece 11 when forming the foam piece 11 . The end piece 12 includes a front surface 14 angled to match the corner of its particular vehicle, and a notched back surface 15 shaped to mateably receive an end of the bumper beam 16 that it rides on. It is contemplated that different attachment means can be used to attach pieces 11 and 12 together, including adhesive, mechanical attachment, different tabs for insert-molding into the foam, and barb-like tabs that can be poked into the foam, etc. Since the same center piece is used for a number of different models, the overall cost of molding dies is greatly reduced. Restated, the cost of several small injection-molding dies for molding a variety of different end pieces and one large die for the foam center piece is much lower than the cost of making a multitude of different huge dies.

A second energy absorber 10 A ( FIGS. 4-7 ) is mounted to a face of a bumper beam 8 and includes a center-located injection-molded non-foam plastic center piece 20 , foam pieces 11 attached to each end of the center piece 20 , and injection-molded non-foam end pieces 12 attached to outer ends of each of the foam pieces 11 . The pieces 11 , 12 , and 20 are each molded for optimal localized energy absorption (i.e. for an optimal force versus deflection curve, as well as for total energy absorption based on localized/area-specific impacts and based on particular types of impacts). For example, the injection-molded pieces 12 and 20 include a plurality of interconnected webs forming a honeycomb structure capable of substantial energy absorption prior to deflection of the bumper beam itself.

A modified bumper system ( FIGS. 8-9 ) includes a roll-formed B-shaped bumper beam 16 and a modified energy absorber 30 B abutted against its face surface. The energy absorber 30 B ( FIGS. 10-11 ) includes an injection-molded piece 31 B, and multiple foam pieces 11 B molded onto the injection-molded piece 31 B. The injection-molded piece 31 B ( FIG. 12 ) is molded of a non-foamed “solid” polymer and includes molded end sections 32 B (similar to end pieces 12 ), and molded center and intermediate sections 33 B and 34 B, all interconnected by longitudinal straps 35 B. The end sections 32 B each include a triangular outer portion 36 B and a triangular inner portion 37 B forming a rearwardly-swept angled front surface 38 B and a stepped back surface 39 B with a pocket 40 B shaped to receive the end of the beam 16 . The outer portion 36 B includes four parallel walls 41 B that extend parallel a length of the beam 16 , and that combine with angled walls 42 B and 43 B to define a honeycomb-like structure in the form of three forwardly open pockets 44 B. The inner portion 37 B has four parallel walls 45 B that combine with angled walls 46 B and 47 B to define a rigid structure on the face of the end of the bumper beam 16 . The honeycomb-like structure of the outer portion 36 B and the inner portion 37 B combine to provide optimal energy absorption at ends of the bumper beam 16 for optimal corner impact resistance and crush characteristics. The walls 41 B and 45 B are generally parallel and aligned with each other and extend in a horizontal plane (when in a car-mounted position), such that good corner impact strength is provided. It is noted that the inner and outer portions 36 B and 37 B are configured to allow a simple molding die, without the need for making undercuts, blind surfaces, and without the need for complex die pulls and slides.

The center and intermediate sections 33 B and 34 B each comprise rearwardly-open box-shaped sections formed by side walls 50 B, a top wall 51 B, a bottom wall 52 B and a front wall 53 B. An opening 54 B is formed in each of the front walls 53 B, and a centered tubular “crush tower” of material 55 B extends rearwardly from the marginal material forming the opening 54 B to a rear of the energy absorber. The box-like shape of walls 50 B/ 51 B/ 52 B/ 53 B along with the crush tower 55 B adds considerably to the impact strength of the energy absorber 30 B and adds to control over the crush sequence and characteristics of impact and bumper system crush stroke versus energy absorption. If the crush tower 55 B ends short of the bumper beam 16 , then the crush sequence has a stepped function, where the initial crush strength is a little lower, and when energy absorber 30 B crushes to the point where the crush tower 55 B hits the bumper beam 16 , the impact strength suddenly increases for additional crush stroke distances. Also, the top and bottom walls 51 B and 52 B are wavy or undulated to provide increased impact strength.

The straps 35 B ( FIG. 12 ) extend between and interconnect each of the sections 32 B, 33 B, and 34 B. Their cross sections define a rearwardly-facing U-shape, and are formed by front wall 57 B, and top and bottom walls 58 B and 59 B. The straps 35 B permit flexing movement, until the foam sections 11 B are molded onto the pieces 31 B, at which time the energy absorber 30 B becomes stiff enough to easily handle and assemble onto the bumper beam 16 .

It is noted that the entire illustrated energy absorber 30 B is configured so that it can be molded by a relatively simple molding die, where the die does not include draws, slides, and other moving complex components for making blind and/or hidden surfaces. This greatly simplifies and improve tooling, and reduces costs of making the die and keeping the die maintained and operational.

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

Claims

1. A bumper system comprising:a bumper beam having a face and ends; and an energy absorber mounted on the face, the energy absorber having a foam piece engaging the face and an injection-molded end piece securely attached to an end of the foam piece and also engaging the face.

2. The bumper system defined in claim 1, wherein the injection-molded end piece includes attachment flanges that extend into the foam piece and anchor the injection-molded end piece in the foam piece.

3. The bumper system defined in claim 1, wherein the injection-molded end piece is insert-molded into the foam piece during the process of molding the foam piece.

4. The bumper system defined in claim 1, including a second injection-molded piece securely attached to a second end of the foam piece.

5. The bumper system defined in claim 4, wherein the second injection-molded piece comprises a second injection-molded end piece.

6. The bumper system defined in claim 5, including a second foam piece and a center-located third injection-molded piece, the first and second foam pieces being securely attached to ends of the center-located third injection-molded piece, and the first and second end pieces being attached to outer ends of the first and second foam pieces, respectively.

7. A bumper system comprising:a bumper beam having a face and ends; and an energy absorber mounted on the face, the energy absorber having at least one foam piece engaging the face and at least one non-foam plastic piece securely attached to an end of the foam piece and also engaging the face, the foam piece and the non-foam piece forming a single member that can be handled and attached as a unit to the bumper beam.

8. A bumper system comprising:a bumper beam having a face surface; and an energy absorber engaging the face surface, the energy absorber having an elongated non-foam component with at least three longitudinally-spaced enlarged sections and a plurality of foam sections attached to the non-foam component between the enlarged sections, at least one of the enlarged sections including a front wall with marginal material forming an opening therein.

9. The bumper system defined in claim 8, wherein the foam sections each fill a space defined between sides of the adjacent enlarged sections.

10. The bumper system defined in claim 8, wherein the enlarged sections are each box-shaped and have a hollow interior space.

11. A bumper system comprising:a bumper beam having a face surface; and an energy absorber engaging the face surface, the energy absorber having an elongated non-foam injection-molded component with at least three longitudinally-spaced enlarged sections and a plurality of foam sections attached to the molded component between the enlarged sections; wherein the enlarged sections are each box-shaped and have a hollow interior space, and further wherein the enlarged sections each include a front wall with marginal material forming an opening therein.

12. The bumper system defined in claim 11, including a crush tower tube that extends from the marginal material rearwardly toward the bumper beam.

13. The bumper system defined in claim 8, wherein the non-foam component is one-piece and the enlarged sections are interconnected by connecting straps.

14. The bumper system defined in claim 8, wherein the non-foam component includes end piece sections and wherein the enlarged sections include at least one centered box-shaped section.

15. The bumper system defined in claim 8, wherein a front surface of the energy absorber includes first areas defined by the non-foam component, and further includes second areas defined by the foamed sections.

16. The bumper system defined in claim 8, wherein the non-foam component includes end sections each having a pocket shaped to receive an end of the bumper beam.