Patent Application
20080012364
The present disclosure generally relates to an improved vehicle bumper assembly and more particularly relates to a vehicle bumper assembly including a hollow tubular corrugated absorber. In one embodiment, the vehicle bumper assembly includes a bumper beam extending laterally across a front or rear of the vehicle connecting frame rails of the vehicle and further includes a hollow tubular corrugated absorber secured to the bumper beam on an opposite side relative to the frame rails, e.g., between the bumper beam and a fascia or wall defining the body of the vehicle. The improved vehicle bumper assembly will be described with a particular reference to this embodiment, but it is to be appreciated that the vehicle bumper assembly is also amenable to like applications.
Prior art bumper assemblies are known to include a rigid bumper beam extending laterally across the vehicle in which the bumper assembly is deployed. The bumper beam is usually provided at either a forward end of the vehicle to absorb a front end collision or a rearward end of the vehicle to absorb a rear end collision. Typically, the bumper beam is held in its forward or rearward position by the vehicle's longitudinally extending frame rails. Aluminum, including extruded aluminum, and steel are favored materials for use in forming bumper beams, and one favored shape for a bumper beam is a hollow, closed-profile B-shape.
Many bumper assemblies further include a shock absorber secured or mounted to the bumper beam on an outside surface or side thereof. For example, the absorber is positioned forward of a front bumper beam and rearward of a rear bumper beam (in either case, the absorber is usually positioned on an opposite side of the bumper than the frame rails). Shock absorbers can be included for the purpose of absorbing energy otherwise imparted to a pedestrian during a vehicle/pedestrian collision, which is sometimes required for a vehicle to meet pedestrian lower leg requirements. Many such absorbers are formed of a polymer or foam having a solid or uniform profile. A body member or bumper fascia can be employed to cover the bumper assembly.
One drawback of these types of absorbers is the high manufacturing costs associated with forming the molded absorber and/or installing the molded absorber on a vehicle. For example, the molding process can be costly and mounting the molded absorber to the bumper beam can be difficult. There is also the potential for density inconsistencies or imperfections resulting from the molding process which can adversely impact the performance of the absorber, particularly along the length of the absorber. Another drawback associated with polymer or foam absorbers is that performance of the absorber can be hindered when extreme temperature conditions are encountered. Another general concern with any bumper assembly is its overall weight and any reduction thereof that can be achieved without comprising safety is considered desirable.
According to one aspect, a vehicle bumper assembly is provided. More particularly, in accordance with this aspect, the vehicle bumper assembly includes a bumper beam extending laterally across a vehicle at one end of the vehicle and a tubular absorber having a closed hollow profile including at least one wall formed of a corrugated layer. The tubular absorber is mounted to and extends along the bumper beam on an outer side thereof.
According to another aspect, a vehicle bumper assembly is provided. More particularly, in accordance with this aspect, the vehicle bumper assembly includes a bumper beam connected to one end of a pair of spaced apart vehicle frame rails. A corrugated tubular absorber has a closed hollow profile and extends longitudinally adjacent and along the bumper beam. The absorber has at least a corrugated metal foil layer.
According to still another aspect, a vehicle bumper assembly mounted to frame rails of a vehicle on the front or rear end of the vehicle is provided. More particularly, in accordance with this aspect, the bumper assembly includes a bumper beam extending laterally across the vehicle and an energy absorbing tube disposed on an outer face of the bumper beam for absorbing energy when the tube is deformed due to an impact force. The energy absorbing tube has a longitudinal length that extends longitudinally along the outer face of the bumper beam and includes a corrugated metal foil layer.
Referring now the drawings wherein the showings are for the purposes of showing one or more exemplary embodiments,
More particularly, in the illustrated prior art bumper assembly 10, the bumper beam 12 has a tubular design and is formed generally with a “B” shape. For purposes of limiting injury to pedestrians in the event of a collision with the vehicle V, a shock-absorber 16 is positioned forward of the bumper beam 12 and frame rails 14 and is secured to the bumper beam 12 for absorbing energy otherwise imparted to the pedestrian in the event of a pedestrian accident. As is well known to those skilled in the art, the absorber 16 can be formed of a polymer or foam, or any other suitable cushioning material. The absorber 16 can have a generally solid or uniform profile or can be a partially hollow plastic injection molded part. As illustrated, the shock-absorber 16 can be specifically positioned between the bumper beam 12 and a bumper fascia 18 provided on an exterior of the vehicle immediately below vehicle air intake or grill 20 which is disposed adjacent a forward end of hood 22.
With reference now to
More particularly, the illustrated bumper beam 32 has a closed cross-section having an upper wall 32a, a middle wall 32b, and a bottom wall 32c. The walls 32a-c are spaced apart from one another in generally horizontal planes, generally parallel to the direction in which the frame rails 34, 36 extend. The bumper beam 32 further includes walls 32d and 32e which are spaced apart from one another in generally vertical planes and are attached to ends of the walls 32a-c to give the bumper beam 32 its B-shape. With brief reference to
Returning reference to
In the illustrated vehicle bumper assembly 30, the absorber 40 is secured or mounted to the bumper beam 32 by a plurality of fasteners 44 (only one shown in
More particularly, with additional reference to
The walls 40a and 40b of the absorber 40 are spaced apart from and opposite one another. Additional walls 40c,40d connect ends of walls 40a,40b to one another to form a generally hollow quadrilateral profile as shown (rectangular in the illustrated embodiment). Alternatively, the walls 40a-d can be referred to as wall portions because, as illustrated, the walls 40a-d of tube 40 form a generally continuous single wall having the aforementioned rectangular profile. The hollow profile of the absorber 40 forms the absorber as a rectangular tubular structure (i.e., not solid or uniform in thickness) along the outer side of the bumper beam 32. The absorber 40 can have a curvature generally matching that of the bumper beam 32. More particularly, the absorber 40 can have a slightly curved structure or curvature, matching that of the bumper beam 32, which includes center portion 40e disposed between the frame rails 34,36 spaced forwardly relative to end portions 40f,40g, which are formed outwardly relative to the frame rails.
At least one wall of the absorber is formed of a corrugated layer. In the illustrated embodiment, the at least one wall includes a first flexible material layer, a second flexible material layer spaced apart from the first layer, and the corrugated layer disposed between the first and second flexible material layers. More particularly, in the illustrated embodiment, each of the walls 40a-d is corrugated and has a corrugated metal foil layer flanked by flexible material layers to provide improved deflection characteristics upon occurrence of a force bearing collision. Since the walls 40a-d are generally alike, only wall 40b is further described herein. Particularly, with specific reference to
The outer and inner layers 54, 58 can be formed of a lightweight, flexible (but environmentally stable) sheet material that is generally water resistant. Examples of suitable sheet materials for the layers 54,58 include those sold under the trademarks Nomex® and Mylar®, but can also include any similar material able to handle general environmental conditions, including temperature, moisture, etc., that an exterior vehicle component is likely to encounter. The corrugated layer 60 can be a corrugated metal foil (e.g., aluminum or steel foil). In one embodiment, the thickness of the inner and outer layers 54, 58 can be approximately 2 mm and the thickness of the corrugated layer 60 can be approximately 5 mm. In the illustrated embodiment of
In one alternate arrangement (not shown), the corrugations of layer 60 could be oriented generally vertically such that ribs of the foil layer are generally parallel to the height of the Vehicle V. In another alternate arrangement, with reference to
In the event of a vehicle collision, particularly where the impact force is not overwhelming, such as in a collision between a pedestrian and vehicle V having the bumper assembly 30 with the hollow tubular absorber 40 (or the absorber 40′), the absorber will crush without significantly impacting the bumper beam 30. In particular, the absorber 40 or 40′ can absorb all or at least a significant portion of a relatively small impact force (e.g., an impact force resulting from a low speed collision with a pedestrian) through deformation or collapsing of the absorber. The specific crush dynamics of the absorber are largely dependent upon the precise configuration of the tubular absorber (including the corrugated layer) and the materials employed to manufacture the absorber (particularly the materials used to form the corrugated layer). In any case, the tubular absorber 40 or 40′ provides a bumper assembly 30 that is very flexible in design. For example, the stiffness properties of the absorber, and therefore the overall bumper assembly 30, can easily be modified with minimal process changes (i.e., no expensive tooling changes).
With reference now to
The primary difference between the absorbers 40 and 72 is that absorber 72 has a hollow trapezoidal profile. That is, rear or mounting wall 72a, which is secured to the bumper beam 32, has a length different than that of spaced apart front or forward wall 72b. In the illustrated absorber 70, the mounting wall 72a has a length or height greater than that of wall 72b. Walls 72c,72d continue to connect ends of walls 72a,72b to one another but, due to the shorter length of wall 72b and its positioning relative to wall 72a, at least one of the walls 72c,72d (both in the illustrated embodiment) extends at an acute angle from wall 72a in connecting to wall 72b. Stated alternatively, at least one of the walls 72c,72d (both walls in the illustrated embodiment) extends at an obtuse angle from front wall 72b in connecting to wall 72a. All of the walls 72a-d can be formed as described in reference to wall 40b (i.e., having a corrugated metal foil layer interposed between flexible material layers) and can be formed as a single or unitary wall structure, as illustrated. Alternatively, the absorber 70 can have its walls formed as described in connection with absorber 40′ and wall 40b′.
The trapezoidal shape of absorber 72, particularly the illustrated trapezoidal shape, may provide a more compact design for better fitting within a space between the fascia 42 and the bumper beam 32 and/or may provide more desirable crush characteristics in the event of a vehicle collision wherein a force is imparted to the bumper assembly 70. Like the absorber 40, the absorber 70 can include a curvature that generally matches that of the bumper beam 32 and the walls 72a-d can be formed by spaced apart material layers with a corrugated layer positioned therebetween.
With reference to
In most respects, except as described herein, the absorbers 84,86 can be the same or similar to the absorber 40. More particularly, like the absorber 40, each of the absorbers 84,86 has a generally hollow rectangular profile, though the profiles for absorbers 84,86 are narrower than that of the absorber 40 in the respective illustrated embodiments. As shown, the absorber 84 has a mounting wall 84a which can be mounted against the bumper beam 32 and a forward wall 84b spaced apart from the wall 84a. The wall 84b can be spaced apart from the mounting wall 84a a fixed distance along the elongated length of the absorber 84 and together the walls 84a,84b can define a curvature that generally matches that of the bumper beam 32. Relatively short connecting walls 84c,84d connect ends of the walls 84a,84b to one another. All of the walls 84a-d can be formed like wall 40b with a flexible material layer spaced apart from another flexible material layer and a corrugated foil layer disposed between the flexible material layers. The absorber 86 can be the same as the absorber 84, but mounted against absorber 84 rather than bumper beam 32. Thus, the absorber 86 can include vertical walls 86a,86b and connecting walls 86c,86d, wherein all walls 86a-d can be formed like wall 40b of
With reference to
More particularly, absorber 98 is wrapped about and adjacent absorber 96 and absorber 96 is wrapped about and adjacent absorber 94. The walls of the absorbers 94,96,98 can be constructed as described in reference to wall 40b. That is, the walls forming the absorbers 94,96,98 can each include a corrugated foil layer having flexible material layers disposed on both sides of the foil layer. In most other respects, the absorber 92 is the same or similar as the absorber 40, including its mounting to bumper beam 32 and its radius or curvature matching the bumper beam 32. Alternatively, one or more of the absorbers 94,96,98 can be formed like the absorber 40′ and have walls like wall 40b′. In one alternate embodiment (not shown), the absorber 92 can be formed of a continuous wall that forms first absorber 94, then wraps therearound to form absorber 96 before wrapping around again to form absorber 98. In another alternate embodiment (not shown), the absorber 92 can be formed as only two absorbers (e.g., absorber 98 stacked on absorber 96 without the use of absorber 94 and/or absorber 92 formed of a continuous wall that only forms two absorbers, e.g., absorbers 96 and 98).
With reference to
The absorber assembly 102 can generally have a curvature matching bumper beam 32 and can be mounted or secured to the bumper beam on a side (the outer side) of the bumper beam opposite the frame rails 34,36 and between the bumper beam 32 and the fascia 42. The attachment of the absorber assembly 102 can be as described in relation to any of the above-described embodiments and/or as generally understood by those skilled in the art. For example, though not shown in the illustrated embodiment, the absorbers 104,106 can be housed within the frame absorber 108 and leg portions 108a,108b can be secured to the bumper beam 32. In one alternate embodiment, frame absorber 108 can be employed with only tubular corrugated absorber 104 received therein. In another alternate embodiment, the absorbers 104,106 can be mounted to the bumper beam 32 without the use of U-shaped absorber 108.
With reference to
The primary difference between the absorbers 40 and 112 is that the absorber 112 has a hollow trapezoidal profile. That is, rear or mounting wall 112a, which is secured to the bumper beam, has a length different than that of spaced apart front or forward wall 112b. In the illustrated absorber 112, the mounting wall 112a has a length or height less than that of wall 112b. Walls 112c,112d continue to connect ends of walls 112a,112b to one another but, due to the longer length of wall 112b and its positioning relative to wall 112a, at least on of the walls 112c, 112d extends at an obtuse angle from wall 112a in connecting to wall 112b. Stated alternatively, at least one of the walls 112c, 112d extends at an acute angle from the front wall 112b to wall 112a. As illustrated, one of the connecting walls, e.g., wall 112d in the illustrated embodiment, can extend at an angle approximately normal relative to walls 112a, 112b. All of the walls 112a-d can be formed as described in reference to 40b (i.e., having a corrugated metal foil layer interposed between flexible material layers or at least having a corrugated metal foil layer) and can be formed as a single or unitary wall structure, as illustrated. Alternatively, the absorber 112 can be formed like the absorber 40′ with its corrugated walls (such as wall 40b′)
With reference to
The primary difference between the absorbers 40 and 122 is that the absorber 122 has a hollow trapezoidal-like profile and has an opposite wall 122b that has a vertical curvature generally matching a vertical curvature of the vehicle fascia 42. More particularly, rear or mounting wall 122a, which is secured to the bumper beam 32, has a length different than that of spaced apart opposite wall 122b. In the illustrated absorber 122, the mounting wall 122a has a length or height less than that of wall 122b. Walls 122c,122d continue to connect ends of walls 122a,122b to one another but, due to the shorter length of wall 122a and its positioning relative to 122b, at least one of the walls 122c,122d extends at an obtuse angle from wall 122a (both walls 122c,122d extend at obtuse angles relative to wall 122a in the illustrated embodiment). As illustrated, the opposite wall can be positioned closely adjacent (or can even be in engagement with) the vehicle fascia 42. All of the walls 122a-d can be formed as described in reference to the wall 40b (i.e., having a corrugated metal foil layer interposed between flexible material layers) and can be formed as a single or unitary wall structure, as illustrated. Alternatively, instead of being formed like absorber 40, the absorber 122 can be formed like the absorber 40′ having corrugated walls (such as wall 40b′)
With reference to
The primary difference between the absorbers 40 and 132 is that the absorber 132 has an opposite wall 132b that has a vertical curvature generally matching a vertical curvature of the vehicle fascia 42. Like the absorber 40, the absorber 132 includes a rear or mounting wall 132a that is secured to the bumper beam 32. The opposite wall 132b, which has a curvature generally matching that of the fascia 42, is spaced apart from the mounting wall 132a and connected therewith by a pair of connecting walls 132c,132d, both of which extend from the mounting wall 132a in a direction approximately normal relative to the mounting wall 132a. As illustrated, the opposite wall 132b can be positioned closely adjacent (or can even be in engagement with) the vehicle fascia 42. All of the walls 132a-d can be formed as described in reference to the wall 40b (i.e., having a corrugated metal foil layer interposed between flexible material layers) and can be formed as a single or unitary wall structure, as illustrated. Alternatively, the absorber 132 can be formed similar to the absorber 40′ having corrugated walls (such as wall 40b′).
With reference to
With reference to
With respect to any of the absorbers disclosed herein, it is to be appreciated by those skilled in the art that any of such absorbers (e.g., absorbers 40 and 40′) can be provided with only one of the inner and outer layers or without both of the inner and outer layers. In one alternate embodiment (not shown), the corrugated wall or walls of the absorber are formed without one or both of the flexible material layers. In another alternate embodiment (not shown) the corrugated wall or walls of the absorber are formed with one or both of the flexible material layers, but one or both of the flexible material layers formed with the corrugated wall or walls are peeled off or from the absorber subsequent to forming absorber (i.e., post-forming).
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
