Front hood, vehicle with such front hood as well as method for producing the same

Abstract

A front lid for a vehicle, especially a motor vehicle, which front lid includes an outer panel, where, in a predetermined region or in the entire area of the front lid below the outer panel, at least one inertia mass is arranged, and the inertia mass is formed of a flexible heavy layer.

Claims

1. A front lid for a motor vehicle, comprising: an outer panel; and an inertia mass arranged in a predetermined region or in the entire area of the front lid below the outer panel; wherein said inertia mass is formed of a flexible heavy layer.

2. The front lid according to claim 1, wherein the inertia mass in the form of the heavy layer is formed as a matt-like built-on or built-in partmass pad, or wherein the inertia mass in the form of the heavy layer is injected into a cavity formed between the outer panel and an internal structure that is attached to the outer panel to provide stiffening hardening.

3. The front lid according to claim 1, wherein the inertia mass in the form of the heavy layer contains a bituminous composition.

4. The front lid according to claim 3, wherein the heavy layer has a density of 2.0 to 2.6 g/cm.sup.3.

5. The front lid according to claim 3, wherein the bituminous composition contains plastics.

6. The front lid according to claim 1, wherein the inertia mass in the form of the heavy layer contains a flexible rubber-based plastic composition.

7. The front lid according to claim 6, wherein the heavy layer has a density of 2.0 to 2.2 g/cm.sup.3.

8. The front lid according to claim 7, wherein the plastic composition furthermore contains foreign plastics.

9. The front lid according to claim 5, wherein the heavy layer, as a matt-like built-on or built-in componentmass pad, on its backside comprises a planar element for stabilizing the bituminous composition or plastic composition and/or, at least on its top side, comprises adhesive means for attaching the heavy layer to the backside of the outer panel.

10. The front lid according to claim, wherein at least the outer panel comprises aluminum or an aluminum alloy, magnesium, plastics, fiber-reinforced plastic or another suitable light-weight construction material.

11. A motor vehicle, having a front lid according to claim 1.

12. A method for manufacturing of a front lid for a motor vehicle, which front lid comprises an outer panel, wherein in a predetermined region or in the entire area of the front lid below the outer panel at least one inertia mass is arranged, wherein a flexible heavy layer is used as an inertia mass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the following, exemplary embodiments of the inventions of the disclosure are explained in more details by way of the working examples, schematically represented in the drawings. However, it is not limited thereto, but encompasses all configurations as set forth in the claims. In the drawings:

[0016] FIG. 1, very schematically, shows a side view of a vehicle including a front lid formed according to the invention;

[0017] FIG. 2 shows a schematic sectional view of the front lid of FIG. 1, representing an inventive inertia mass of the front lid according to a first variant of the invention in the form of a mass pad (line, I-I in FIG. 3);

[0018] FIG. 3 shows a back layer of the front lid of FIG. 2;

[0019] FIG. 4 shows an inertia mass modified in relation to FIG. 2 and formed as a mass pad;

[0020] FIG. 5 shows a second variant of the invention;

[0021] FIG. 6 shows a diagram including three acceleration (a) time (t) curves A, B, C, which curve A relates to a front lid panel of steel and the curves B and C each relate to a front lid panel of a specified aluminum alloy having an inventive inertia mass, and

[0022] FIG. 7 shows a diagram having three acceleration (a) time (t) curves A, B, C, which curve A relates to a front lid panel of steel and the curves B and C each relate to a front lid panel of a specified aluminum alloy lacking an inertia mass (prior art).

DETAILED DESCRIPTION

[0023] FIG. 1 shows a vehicle 1, which, in the present disclosure, is a passenger car, having a front lid 2, which, according to this embodiment, is manufactured of aluminum alloy sheet. However, the invention is not limited to aluminum or said aluminum alloy as a material, but also encompasses any suitable light-weight construction material, such as for example magnesium, plastics or even fiber-reinforced plastics. According to FIGS. 2 to 4, the front lid 2, in the closed state thereof, has an outer top panel 3 as well as an underlying internal structure 4 firmly bonded to the outer panel 3. The outer panel 3 and the internal structure 4 are firmly bonded to each other in selected regions, for example are glued to each other. Said internal structure 4 essentially is for stiffening the front lid 2. The internal structure 4 may be formed as a closed planar element, eventually including stiffening ribs (not shown in the drawings) or the like. Alternatively, it may have at least one recess 9 in predetermined regions (FIG. 3). Moreover, the internal structure 4, in predetermined regions, is arranged spaced apart from the outer panel 3. The predetermined regions, formed of said recess(es) 9 in the internal structure 4 and/or said spacing(s), are provided, among others, at locations, which, in case of an eventual collision of the vehicle 1 with a pedestrian, the same would presumably hit with his head, as it has been revealed as a result of extensive trials.

[0024] In order to at least effectively minimize the harmful effects of this collision for the respective pedestrian, at least one inertia mass 5 is arranged at least in said predetermined regions below the outer panel 3 on the same. In the present invention, the inertia mass 5 is formed of a flexible heavy layer 5a, 5b.

[0025] Variant 1 (FIGS. 2 to 4):

[0026] According to the FIGS. 2 and 3, the flexible heavy layer 5a is formed as a matt-like built-on componentmass padand, on its top side, having an adhesive means 6 or being provided with such to become attached in the region of the recess 9 to the backside of the outer panel 3. In FIG. 3, only two recesses 9 are shown as an example, wherein, in each of which, a mass pad of the heavy layer 5a is arranged. The adhesive means 6 is for example formed of a self-adhesive acrylate adhesive.

[0027] Contrary to this, FIG. 4 shows a flexible heavy layer 5a in the form of a mass pad, which is introduced or inserted, respectively, as a matt-like mounting component into a cavity 8 formed between the outer panel 3 and the internal structure 4. According to this working example, gluing the mass pads to each other was omitted, but may of course be provided, if this is considered as being suitable.

[0028] According to a preferred first embodiment of this first variant, the heavy layer 5a contains a bituminous composition having a density of 2.0 to 2.6 g/cm.sup.3. However, the invention is not limited to that specified density, but also encompasses density values different therefrom, preferably those that are correspondingly higher. For conferring advantageous characteristics to the bituminous composition, especially suppressing hardening or embrittling of the bituminous composition, as well as setting a specific elasticity or flexibility, the bituminous composition preferably comprises a plastic material. That plastic material, for example, may be formed by a copolymer, such as for example polypropylene.

[0029] For stabilizing the bituminous composition in the form of the matt-like built-on partsmass padsespecially at high temperatures during introduction of the same into the vehicle shell, it is preferably provided that the composition, at least at its backside, contains or comprises a planar element 7. Said planar element 7 may, for example, be formed of a batt or nonwoven web of synthetic or natural fibers, such as a batt or nonwoven web of glass fiber, which batt or nonwoven web will then be impregnated with the bitumen (FIGS. 2 and 4). Alternatively, one or more sheets of paper or the like may be provided as a lower end of the heavy layer 5a sein (not shown in the drawings).

[0030] Of course, it is understood by the person skilled in the art and is as well encompassed by the invention that not only one sheet of mass pads may be provided, but, at least in certain regions, also two or more sheets be arranged one over the other to allow optimal adjustment of the mass inertia of front lids 2 (not shown in the drawings) in view of a smallest possible H1C value.

[0031] In trials concerning the disclosure, the following exemplary composition for the above described mass pad having bituminous composition has been proven successfully:

TABLE-US-00001 mixture of bitumen 8-20% thermoplastic polymers 15-20% rubbers 2-6% mineral fillers 5-10% heavy fillers, such as ferrous oxide 38-50% modifiers and stabilizers 8-12%

[0032] The above-described composition allows manufacture of a mass pad especially having the following parameters: [0033] density: 2.0-2.6 g/cm.sup.3 [0034] thickness: 2-6 mm [0035] basis weight: 4-16 Kg/m.sup.2 [0036] thermal stability 210 C. in perpendicular as well as overhead position during 45 min [0037] high cold flexibility [0038] resistance against aqueous and alcoholic solutions, diluted acids and baseslong term functional insulation and damping characteristics

[0039] Thus, such a bitumen-based mass pad, after having been modified by polymeric portions, appropriate fillers and functional additives, shows good flexibility, thermal stability as well as long-term corrosion protection performance. By the use of a high quality pressure sensitive adhesive based on said acrylate, good adhesion even on lubricated or oiled aluminum sheet is possible.

[0040] According to a previously described alternative second embodiment of said first variant, the heavy layer 5a contains a flexible rubber-based plastic composition. Preferably, it is a butyl rubber, which generally is also referred to as butyl. It is furthermore preferred, that said plastic composition has a density of about 2.0 to about 2.2 g/cm.sup.3. However, the invention is not limited to those density specification concretely described, but also encompasses density values differing therefrom, preferably those that are correspondingly higher. For also conferring advantageous characteristics to that plastic composition, especially suppressing hardening or embrittling of the same, said plastic composition, especially in the form of the butyl rubber, comprises extrinsic plastics. As an extrinsic plastic material, for example thermoplastic elastomers and/or polyamide compounds are suitable. According to the above-described first embodiment, it may be provided that also the plastic composition, on its backside, contains or comprises a planar element 7 of the previously described type for stabilizing the plastic composition.

[0041] In trials concerning the the application, the following exemplary composition has proven to be successful for this mass pad having flexible plastic composition:

TABLE-US-00002 solid thermo-elastic butyl rubber 3-7% oligomeric and low molecular liquid 10-16% butyl compounds thermoplastic elastomers 4-10% thermoplastic polyamide compounds 1-3% plastic resins 4-8% heavy fillers 50-65% stabilizers and pigments 3-5% thixotropic materials 2-5%

[0042] The composition above allows manufacture of a mass pad especially with the following parameters: [0043] density: 2.0-2.2 g/cm.sup.3 [0044] thickness: 2-6 mm [0045] basis weight: 4-13 Kg/m.sup.2 [0046] thermal stability 210 C. in perpendicular position as well as overhead position within 45 min [0047] adhesion to oiled substrates, [0048] resistance against aqueous and alcoholic solutions, diluted acids and bases

[0049] Such a mass pad has self-adhesive as well as thermoplastic characteristics. Following mounting and submission to the standard vehicle manufacturing method the mass pad functions as an elastomer. Essentially, only the effect of the mass as well as insulation effects are to be seen. There are no merely stiffening and attenuating effects to be seen.

[0050] Variant 2 (FIG. 5):

[0051] This variant essentially differs from the above in that, according to FIG. 5, the heavy layer 5b formed by a bitumen- or plastic composition will not be provided as a mass pad, but is injected as a viscous mass into a cavity 8 formed by a spacing between the outer panel 3 and the internal structure 4 and is adhered thereto by adhesion and following this sets to a flexible inertia mass 5. The characteristics thereof may also be broadly adjusted by specific portions of ingredients (see above).

[0052] FIG. 6 only exemplary shows a diagram including three acceleration (a) time (t) curves A, B, C, also referred to as head impactor retardation curves, wherein the curve A relates to a front lid panel of steel (prior art) and the curves B and C each relate to a front lid panel of for example a specific aluminum alloy having at least one inertia mass 5 of the present invention. In comparison to prior art (FIG. 7), it may be seen for the front lid panels of an aluminum alloy having inertia mass(es) 5 of the present invention that a first acceleration peak of the curves B,C in relation to the respective front lid 2 of said aluminum alloy is increased to an optimum level (preferably as high as for a front lid 2 of steel) for the deceleration of the head impactor, and in the present disclosure, even exceeds that level. An optimum acceleration course will result (1st acceleration peak of height and 2nd acceleration peak of height). From this, a better HIC value having shorter deformation path of the front lid 2 than conventionally results for the front lid panels of an aluminum alloy used as an example, having inertia mass 5 of the previously described type. Moreover, it is to be noted that the overall mass set according to the invention, of the aluminum panel including inertia mass 5 (heavy layer 5a, 5b) is significantly lower than a steel reference equally performing in relation to HIC and deformation path.

[0053] As to binding the inertia mass 5 (heavy layer 5a, 5b) formed according to the invention and the front lid 2 of the vehicles 1, in relation to the above-described method step CDC (CDC=cathodic dip coating) and dependent on the specific design of the inertia mass 5 as a heavy layer 5a or as a mass pad or as an injected or molded-on heavy layer 5b, respectively, for example, the following methoding steps may result.

[0054] It may, for example, be provided that the inertia mass 5 is first joined to the outer panel 3 in the form of at least one mass pad (heavy layer 5a), and is preferably glued, and subsequently the internal structure 4 is adhered to the outer panel 3. The mass pad is now located between the outer panel 3 and the internal structure 4 (cf. FIG. 2-4), for example in the region of a recess 9 of the internal structure 4 (FIG. 3). Thereafter, the complete front lid 2 is submitted to the CDC method.

[0055] Contrary to this, it may also be provided that after the front lid 2 having been submitted to a CDC method, injectable inertia mass 5 (heavy layer 5b) is injected into a cavity 8 formed between the outer panel 3 and the internal structure 4 (cf. FIG. 5).