JP2008247095A - Engine hood for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine hood for an automobile having light weight and high rigidity and capable of alleviating head damage of pedestrians at the time of a traffic accident. <P>SOLUTION: The engine hood 10 for the automobile is constituted by cutting and raising inner panel members between pairs of parallel slits 18, 18 extended to an advancing direction of the automobile so as to protrude the inner panel members to an outer panel 12 side and forming cut and raised parts 16 so that their width B is ≥10 mm and ≤50 mm; and by adhering outer contact parts 22 which are upper end parts of the cut and raised parts 16 to the outer panel 12 by an adhesive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automobile engine hood, and more particularly to an automobile engine hood that can cope with pedestrian protection in the event of a collision with a pedestrian and is lightweight and highly rigid.

  In general, an engine hood of an automobile is provided so as to be superimposed on an inner surface side of the outer panel as an outer panel and a reinforcing member of the outer panel, and forms a skeleton of the engine hood to ensure the rigidity of the engine hood. It consists of an inner panel.

  In the engine hood having such a configuration, in order to obtain a highly rigid engine hood, as a configuration of an inner panel that can reinforce the engine hood most effectively, a plurality of reinforcing beams are arranged in a lattice shape. A structure is conceivable.

  However, in recent years, in situations where there is a strong demand for pedestrian protection in traffic accidents, when a car collides with a pedestrian, the pedestrian's head often collides with the engine hood, which can be fatal. It is recognized that there is a risk of becoming. For this reason, when the inner panel has a structure in which a plurality of reinforcing beams are arranged in a lattice shape as described above, the intersection of the plurality of reinforcing beams is more rigid than other parts of the engine hood. Therefore, when the automobile collides with a pedestrian, a problem that the pedestrian is more likely to receive a strong impact at the intersection is caused.

  Therefore, in order to deal with such a problem, in Japanese Patent Laid-Open No. 2001-151159 (Patent Document 1), a large number of beads are arranged on a reinforcing panel to be joined to an outer panel, and the bending rigidity is changed from an edge portion to a central portion. In the case of a head collision with any part of the engine hood, the same impact is always obtained. The engine hood that has been made to receive is clarified.

  In addition, in International Publication No. WO02 / 47961 (Patent Document 2), a panel structure in which an outer and an inner are joined in a closed cross-sectional structure through a space, and the inner panel extends over the entire inner surface. A waveform having a waveform shape in which a plurality of waveform beads are provided substantially in parallel, and the cross-sectional shape of which is a sine curve, sine n-th power curve, or spline curve having a wavelength close to the head outer diameter. The engine hood, which has a hood structure, has been clarified. According to such an engine hood, it is supposed that uniform and excellent head collision resistance can be realized irrespective of the position of the collision with the engine hood, and that the stiffness and the like can be increased.

  However, from the standpoint of protecting automobile occupants, the engine hood needs to have high rigidity, and from the viewpoint of environmental protection, there is a demand for improvement in fuel consumption, so that a lightweight one is required. Therefore, there is a need for an automobile engine hood that is lightweight and highly rigid, and that can also protect pedestrians in the event of a collision.

JP 2001-151159 A International publication: WO02 / 47961

  Here, the present invention has been made in the background of such circumstances, and the solution is to reduce the pedestrian's head injury during a traffic accident while being lightweight and highly rigid. It is also possible to provide an automobile engine hood that can be used.

  And in the present invention, in order to solve such a problem, it was made as a result of earnestly studying the structure of the inner panel of the engine hood of the automobile by simulation, and the gist In the engine hood of an automobile composed of an outer panel and an inner panel, the inner panel includes a plurality of a pair of parallel slits extending in the traveling direction of the automobile and an inner panel portion between the pair of slits on the outer panel side. And the upper end of the cut and raised portion is bonded to the outer panel, while the width of the cut and raised portion: W is 10 mm or more and less than 50 mm. It is in the engine hood of an automobile.

  According to one of the desirable aspects of the engine hood according to the present invention, the cut-and-raised portion formed on the inner panel is composed of a cut-and-raised inclined portion and an outer panel contact portion. Become.

  In another desirable aspect of the engine hood according to the present invention, the cut-and-raised portion formed on the inner panel includes a pair of cut and raised inclined portions and a flat outer panel contact portion. It will become the cross-sectional trapezoid shape.

  Furthermore, according to one of the preferable aspects of the present invention, the pair of slits are disposed at an angle of 0 to 20 ° with respect to the traveling direction of the automobile.

  Furthermore, in another preferable aspect of the present invention, the cut-and-raised portions formed on the inner panel are arranged in parallel or staggered with respect to the traveling direction of the automobile.

  Therefore, according to the engine hood configured in accordance with the present invention as described above, the plurality of slits formed in the inner panel are respectively cut and raised so as to protrude toward the outer panel, and the upper end portion of the cut and raised portion. Can be bonded to the outer panel, and the width of the cut-and-raised part: W is 10 mm or more and less than 50 mm, so it has high rigidity and can absorb impact efficiently. Thus, it is possible to provide a lightweight engine hood that can advantageously reduce the pedestrian's head injury value in the event of a traffic accident.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows an embodiment of an automobile engine hood according to the present invention in a bottom view, in other words, in a plan view viewed from the inner panel side. The engine hood 10 has an outer panel 12 on the outside of the vehicle body, an inner side of the vehicle body, and an upper side and a lower side in the vertical direction in the figure corresponding to the longitudinal direction of the automobile. In other words, the inner panel 14 on the engine room side is overlapped, and the end of the inner panel 14 is joined to the outer peripheral edge of the outer panel 12 using a known joining method such as hemming. Has been. In addition, between the inner surface of the outer panel 12 and the inner panel 14, a plurality of (here, 18) cut-and-raised portions 16 provided on the inner panel 14 are partially bonded by an adhesive. Is also bound by.

  More specifically, the inner panel 14 that is superimposed on the outer panel 12 and reinforces the outer panel 12 is formed of an aluminum alloy plate, a high-tensile steel plate, or the like. As shown, a plurality of cut-and-raised portions 16 rising to the outer panel 12 side are provided so as to be spaced apart from each other by a predetermined interval. Here, the cut-and-raised portions 16 having a strip shape, in other words, an elongated belt-like shape, are provided. , Aligned and formed to extend a predetermined length in the traveling direction F of the automobile. That is, a plurality (18 in this case) of the cut-and-raised portions 16 are arranged in two rows with two rows. The number of the cut and raised portions 16 is appropriately adjusted according to the size and shape of the engine hood, and is not limited to 18.

  The cut-and-raised portion 16 is directed to the traveling direction F of the automobile formed on the inner panel 14 as shown in FIG. 2 in which the portion A in FIG. 1 is enlarged and the cross-sectional views in FIGS. The inner panel part between the pair of parallelly extending slits 18 and 18 is processed and formed so as to protrude to the outer panel 12 side. That is, here, the cut-and-raised portion 16 is composed of a pair of sloped and raised portions 20 and 20 and a flat outer contact portion 22 that comes into contact with the outer panel 12, and is a plane parallel to the slit 18. The cut cross-sectional shape is configured to exhibit a trapezoidal shape (see FIG. 4). And such an outer contact part 22 is adhere | attached on the inner surface of the outer panel 12 via the adhesive agent b.

  In this way, a large number of cut-and-raised portions 16 are formed on the inner panel 14, and the outer panel 12 and the outer panel 12 are bonded to each other at the outer contact portion 22 of the cut-and-raised portion 16. And the inner panel 14 are uniformly bonded over the entire surface thereof, so that the rigidity of the engine hood 10 can be uniformly increased over the entire surface.

  The length L1 of the outer contact portion 22 in the cut and raised portion 16 formed on the inner panel 14 is generally preferably 50 mm or more and 300 mm or less. This is because, when the length (L1) of the outer contact portion 22 is less than 50 mm, the deformation area when the impactor collides with the engine hood 10 is reduced, so that the shock absorption capacity is reduced. This is because the effect as a shock absorber is reduced. In addition, when the length is larger than 300 mm, the torsional rigidity of the engine hood 10 is lowered since the length L3 of the slit 18 in the cut and raised portion 16 is substantially larger than 300 mm. is there.

  Moreover, it is preferable that the length L3 of the slit 18 corresponding to the full length (in plan view) of the cut and raised portion 16 is 50 mm or more and 300 mm or less. This is because, when the length (L3) is less than 50 mm, the length of the outer contact portion 22 in the cut-and-raised portion 16 is substantially smaller than 50 mm. This is because the deformation area is reduced and the shock absorption capacity is reduced. On the other hand, when it is larger than 300 mm, the torsional rigidity of the hood inner (inner panel 14) is lowered.

  Furthermore, the length L1 of the outer contact portion 22 is preferably L1> L3 × 0.5. This is because, when L1 ≦ L3 × 0.5, the deformation region at the time of impactor collision is reduced, so that the shock absorption capability is lowered and the effect as a shock absorbing material is reduced.

  Furthermore, the length L2 of the inclined portion 20 preferably satisfies the relationship [(2 × L2) + L1] /L3≦1.35. This is because, when [(2 × L2) + L1] / L3> 1.35, when the inner panel is formed, the amount of strain of the cut and raised portion 16 becomes too large, so that the constriction or breakage occurs. This is because a molding defect such as the above may occur.

  In addition, the width W of the cut and raised portion 16 is set to 10 mm or more and less than 50 mm according to the present invention. This is because, when such a width is less than 10 mm, the deformation region at the time of impactor collision is reduced, so that the shock absorption capability is reduced and the effect as a shock absorber is reduced. . On the other hand, if it is larger than 50 mm, the torsional rigidity of the hood inner (inner panel 16) is lowered.

  The height H of the cut-and-raised portion 16 is preferably 10 mm or more and 50 mm or less. The height H of the cut-and-raised portion 3 is extremely thin because the adhesive b layer is extremely thin. 3, the distance between the outer panel 12 and the inner panel 14 is substantially the same, and it is desirable that this distance be within such a range. The distance between the outer panel 12 and the inner panel 14 depends on the design of the automobile, but if it is less than 10 mm, the torsional rigidity decreases. If it is greater than 50 mm, the distance between the outer panel 12 and the inner panel 14 can be reduced. This is because the contact of this becomes a problem.

  Thus, according to the engine hood 10 of the automobile according to the present invention, since the rigidity in each part is uniform, the pedestrian obstacle value at the time of a traffic accident can be reduced, and the light weight structure is provided. It can also be done. In addition, since it is relatively easy to form the cut and raised portion 16 with respect to the inner panel 14, for example, even if a material having high yield strength among aluminum alloys is used, the forming height can be increased. Accordingly, it is possible to mold the engine hood 10 having high rigidity and high shock absorption.

  As mentioned above, one of the representative embodiments of the present invention and the manufacturing method thereof have been described in detail. However, these are merely examples, and the present invention is specific to such embodiments. It should be understood that the description is not to be construed as limiting in any way.

  For example, in the above-described embodiment, the cut-and-raised portions 16 formed on the inner panel 14 are aligned and arranged so that the long sides of the elongated substantially rectangular shape are parallel to the traveling direction F of the automobile. However, as shown in FIG. 5, the cut and raised portion 16 may be disposed in an oblique direction with an angle (α) of 0 to 20 ° with respect to the traveling direction F of the automobile. Furthermore, as shown in FIG. 6, it is of course possible to arrange the cut and raised portions 16 in a staggered manner.

  Further, it is not necessary to provide R at the corner of the cut and raised portion 16, that is, at the connecting portion between the inner panel 14 and the inclined portion 20, or at the connecting portion between the inclined portion 20 and the outer contact portion 22, When it is difficult, it is possible to provide R of 5 mm or less.

  In addition, although not listed one by one, the present invention is implemented in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the invention.

  In the following, one of the representative embodiments of the present invention will be shown to clarify the features of the present invention. However, the present invention is not restricted by the description of such embodiments. It goes without saying that it is not a thing.

  In order to execute a simulation using commercially available FEM analysis software, first, a mesh model of an inner panel and an outer panel of an engine hood was produced. At that time, assuming that an aluminum alloy plate (AA 6009 equivalent, tempered T4) is used for the engine hood, the material properties after the paint baking process are set for the purpose of carrying out the simulation under conditions closer to the actual hood. Input to the analysis model.

  Furthermore, in the mesh model, a plurality of cut and raised portions 16 as shown in FIGS. 2 to 4 are formed, and these cut and raised portions 16 are connected to FIG. 1 and FIG. It arranged in the form as shown in FIG. In FIG. 7, the cut-and-raised portions 16 are arranged in six rows and four stages so as to extend in a direction orthogonal to the traveling direction of the automobile. In any example, the cut-and-raised portion 16 is provided on the entire inner panel 14 except for the outer peripheral edge portion of the engine hood 10, the vehicle body front portion (lock mechanism mounting portion), and the driver seat side end portion (hinge mounting portion). The outer contact portion 22 is formed on the cut and raised portion 16, and the outer contact portion 22 is assumed to be bonded to the inner side surface of the aluminum outer panel 12.

  Here, the arrangement and shape of the cut-and-raised portions 16 are in accordance with the present invention. 1-No. Six types of mesh models of the engine hood 10 of 6 were prepared, and these were used as examples of the present invention, and their arrangement and shape are shown in Table 1 below. As a comparative example, the arrangement and shape are out of the scope of the present invention. 7-No. Six types of 12 were prepared, and their arrangement and shape are shown in Table 2 below.

  Then, a simulation in which the mesh model impactor collides with the mesh model engine hood in the same manner was performed. At that time, as the analysis condition, a condition corresponding to the collision condition of the child's head in Euro NCAP (European New Car Assessment Program) was input. Specifically, using an impactor having a weight of 2.5 kg and an outer diameter of 130 mm, such an impactor is allowed to collide with several places on the engine hood at a speed of 40 km / h and a collision angle of 50 °. The head disorder value according to the present invention was calculated in Table 1, and the head disorder value in the comparative example was also shown in Table 2. As is well known, the pedestrian head injury value (HIC) is calculated by the following equation (1).

但し、∫はｔ₁ からｔ₂ までの積分値であり、Ａは頭部重心における３軸合成加速度、ｔ₁ ，ｔ₂ は０＜ｔ₁ ＜ｔ₂ となる時刻で、ＨＩＣが最大となる作用時間で、（ｔ₂ −ｔ₁ ）は１５ｍｓｅｃ以下とする。 [formula]

Where ∫ is an integral value from t ₁ to t ₂ , A is a three-axis composite acceleration at the center of gravity of the head, and t ₁ and t ₂ are the time when 0 <t ₁ <t _2, and the HIC is maximized. In terms of action time, (t ₂ -t ₁ ) is 15 msec or less.

  Furthermore, using these mesh models, simulation was performed to restrain the engine hood at the two rear ends, and to give a forced displacement that would twist the entire engine hood, and torsional rigidity of the engine hood was evaluated. At that time, the higher the generated load, the better the torsional rigidity. However, there is no clear criterion for torsional rigidity, and as a conventional engine hood there are several A mesh model of an engine hood using an inner panel in which reinforcing beams of No. 1 are arranged in a lattice shape is produced. 1-No. A simulation was performed in the same manner as for the 12 mesh models, and a relative comparison with the results was performed. And each comparison result was evaluated in three steps of (circle), (triangle | delta), and x, and those evaluation results were combined with the following Table 1 and Table 2, and were shown.

  As is clear from the results of Tables 1 and 2, the test material No. It is recognized that all of Nos. 1 to 6 have excellent head obstacle values in all parts of the engine hood and have sufficient torsional rigidity.

  In contrast, test material No. Since the length L1 of the outer contact part in the cut-and-raised part 7 is short, the impact absorbing effect is small. No. No. 8 has inferior torsional rigidity because the length L1 of the outer contact portion in the cut and raised portion is too long. Furthermore, the test material No. 9 is L1 ≦ L3 × 0.5, and the length L1 of the outer contact portion is shorter than the length L3 of the slit portion, so that the impact absorption effect is small. Furthermore, the test material No. In No. 10, the width W of the cut-and-raised portion is small, and the impact absorbing ability is small due to the decrease in the rigidity against collision. In addition, test material No. No. 11 has inferior torsional rigidity because the width W of the cut and raised portion is too large. In addition, test material No. No. 12, the cut-and-raised portion is disposed at right angles to the vehicle body traveling direction, and the impact-raising effect is reduced because the cut-and-raised portion does not deform uniformly when the impactor collides. The test material No. No. 13 uses a conventional inner panel in which a plurality of reinforcing beams are arranged in a lattice shape on a steel plate, and the rigidity against collision is not uniform and the head impact value is inferior.

  Thus, the test material No. 7 to 13 are all test materials No. Compared with 1-6, the head impact value or torsional rigidity is inferior.

It is lower surface explanatory drawing which shows an example of the engine hood according to this invention. It is explanatory drawing which expands and shows the A section in FIG. It is explanatory drawing which expands and shows the XX cross section in FIG. It is explanatory drawing which expands and shows the YY cross section in FIG. It is lower surface explanatory drawing which shows another example of the engine hood according to this invention. It is lower surface explanatory drawing which shows another example of the engine hood according to this invention. It is lower surface explanatory drawing which shows the arrangement | positioning form of the cut-and-raised part different from this invention examined in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine hood 12 Outer panel 14 Inner panel 16 Cut and raised part 18 Slit 20 Inclined part 22 Outer contact part

Claims (5)

  In an engine hood of an automobile comprising an outer panel and an inner panel, the inner panel projects a plurality of a pair of parallel slits extending in the direction of travel of the automobile and an inner panel portion between the pair of slits toward the outer panel. The cut and raised portion is formed, the upper end of the cut and raised portion is bonded to the outer panel, and the width of the cut and raised portion: W is 10 mm or more and less than 50 mm. Car engine hood.   2. The engine hood for an automobile according to claim 1, wherein the cut-and-raised portion formed on the inner panel includes a cut-and-raised inclined portion and an outer panel contact portion.   The cut-and-raised portion formed in the inner panel has a trapezoidal cross-section made up of a pair of cut and raised inclined portions and a flat outer panel contact portion. The car engine hood as described.   The automobile engine according to any one of claims 1 to 3, wherein the pair of slits are arranged at an angle of 0 to 20 ° with respect to a traveling direction of the automobile. hood. The automobile engine according to any one of claims 1 to 4, wherein the cut-and-raised portions formed on the inner panel are arranged in parallel or in a staggered manner in the traveling direction of the automobile. hood.

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