JP2003191865A - Bonnet structure for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bonnet structure capable of realizing light weight, high rigidity and low damage value, and tuning the damage value and admission volume to ideal values. <P>SOLUTION: A bonnet 1 is arranged in a manner for covering an engine room of a vehicle and mainly constituted with an outer panel 2 and an inner panel 3. A first frame part 4 of an approximately closed cross section shape formed by the outer panel 2 and the inner panel 3 is formed along the outer peripheral edge. A plurality of dimples 6 of an approximately conical trapezoidal shape recessed from the inner panel 3 towards the rear face of the outer panel 2 are formed to the inner panel 3, and a plurality of through-holes 7 are formed around the dimples 6 of the inner panel 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile bonnet structure mainly composed of an outer panel and an inner panel.

[0002]

2. Description of the Related Art A vehicle bonnet is lightweight and highly rigid, and has an injury value (an index representing damage to a pedestrian in a collision. Details will be described later) at the time of collision with a pedestrian.
Is desired, and the amount of entry (the amount of deformation of the bonnet toward the engine room due to a collision) is also desired to be small.

As an automobile bonnet structure mainly composed of an outer panel and an inner panel, for example, Japanese Unexamined Patent Publication No. 2000-168622 and US Pat.
It is known that a plurality of dimples are formed on the inner panel to make the inner panel lighter and more rigid, such as 745.

[0004]

However, in the above-mentioned conventional structure, since the inner panel is provided with only a plurality of dimples, it is difficult to partially adjust the balance between the injury value and the entry amount, and it is not enough. There was a problem that it was difficult to obtain various design freedom.

In view of such circumstances, the present invention realizes lightweight, high rigidity and low injury value, and further, it is easy to optimally design the bonnet so that the injury value and the entry amount are in an ideal balance. It provides the structure.

[0006]

According to a first aspect of the present invention, there is provided a bonnet which is arranged so as to cover an engine room of a vehicle and which is mainly composed of an outer panel and an inner panel. The outer panel and the inner panel form a first frame portion having a substantially closed cross-sectional shape, and the inner panel has a plurality of substantially frustoconical dimples that are recessed from the inner panel toward the back surface of the outer panel. In addition, a plurality of through holes are provided around the dimples of the inner panel.

According to the present invention, since the inner panel is provided with the dimples and a plurality of through holes are provided around the dimples, the bonnet has a lightweight and highly rigid structure, and a pedestrian can hit any part of the bonnet. It has the effect that there is no large bias in the injury value. At this time, by forming the first frame portion along the outer peripheral edge of the inner panel, it is possible to prevent a decrease in rigidity due to the through hole.

Further, by adjusting the diameter and arrangement of the through holes, it becomes easy to optimally design the through hole so that the injury value and the penetration amount are in an ideal balance.

According to a second aspect of the present invention, in the bonnet structure according to the first aspect, the plurality of dimples and the plurality of through-holes have adjacent dimples and dimples in a region where at least three of them are distributed. The intervals are substantially equal, the intervals between adjacent through holes are substantially equal, and the intervals between adjacent dimples and through holes are approximately equal.

According to the present invention, since the dimples and the through holes are substantially evenly distributed, the rigidity of the bonnet is made more uniform, and the effect of preventing a large obstacle value locally at the collision site is enhanced. You can

According to a third aspect of the present invention, in the bonnet structure according to the first or second aspect, the second frame extends from the front portion of the inner panel toward the vehicle rear side in the vehicle width direction central portion of the bonnet. It is characterized in that a portion is formed.

According to the present invention, by providing the second frame portion in the central portion of the bonnet, it is possible to supplement the rigidity of the central portion of the bonnet where the rigidity tends to be low, and to make the rigidity of the entire bonnet more uniform. I can.

According to a fourth aspect of the present invention, in the bonnet structure according to the third aspect, the width dimension of the second frame portion is formed so as to increase toward the rear of the vehicle.

According to the present invention, in the central portion of the bonnet,
By providing the second frame part so that the width becomes wider toward the rear of the vehicle, the rigidity at the rear of the central part of the bonnet, which tends to be low in rigidity, can be supplemented, and the rigidity of the entire bonnet can be made more uniform. .

According to a fifth aspect of the present invention, in the bonnet structure according to the third or fourth aspect, in the inner panel, a non-perforated region where the through hole is not provided is provided in a predetermined range around the second frame portion. It is characterized by

According to the present invention, the rigidity of the central portion of the bonnet, which tends to be low in rigidity, can be further supplemented, and the rigidity of the entire bonnet can be made more uniform.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description, the center means the center in the left-right direction, and the center means the center in the front-rear, left-right direction in the bonnet body.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the bonnet 1.
The outer panel 2 is an outer plate of the hood 1 and is a part of the exterior of the vehicle.

FIG. 2 is a bottom view of the bonnet 1.

The bonnet 1 mainly comprises an outer panel 2 and an inner panel 3, and the inner panel 3 is joined to the outer panel 2 with an adhesive or the like. The outer panel 2 and the inner panel 3 maintain a substantially constant interval, but the inner panel front part 31 which is the front side of the inner panel 3 has a bulge toward the inside of the vehicle, and the interval between the outer panel 2 and the outer panel 2 becomes wider. There is.

The inner panel 3 is provided with a plurality of dimples 6 (21 locations in FIG. 2). Dimple 6
Is a substantially frustoconical (mortar-shaped) depression.

Further, the inner panel 3 is provided with a plurality of through holes 7 (34 locations in FIG. 2).

As shown in FIG. 2, the dimples 6 and the through holes 7 are regularly arranged. The dimple 6 is provided at each vertex of the equilateral triangle on the side a1 in the arrangement area. The through hole 7 is provided at the center of gravity of the equilateral triangle on the side a1. Therefore, the distance between each dimple 6 and the through hole 7 and the distance between the adjacent through holes 7 are both a2, and the relationship between a1 and a2 is a1 = √3 × a2
Becomes

A first frame portion 4 is provided along the left, right and rear edges of the bonnet 1. The first frame portion 4 has a frame shape of a trapezoidal cross section formed by the outer panel 2 and the inner panel 3 bent in a U shape. The front end of the first frame portion 4 is connected to the inner panel front portion 31.

The outer panel 2 and the inner panel 3 are intermittently adhered to each other at the side portions of the first frame portion 4. The bonded portion has a completely closed cross section, while the non-bonded portion has a substantially closed cross section with a slight gap.

FIG. 3 is a Q-Q sectional view of FIG. 2, and FIG. 4 is a RR sectional view of FIG. FIG. 5 is a cutaway perspective view showing a part of the outer panel and the inner panel.

As shown in FIGS. 3 to 5, the portion of each dimple 6 corresponding to the bottom of the mortar is bonded to the outer panel 2 with an adhesive 8.

Due to the above structure, the bonnet 1
The first frame portion 4 has the highest rigidity in the vicinity of the outer peripheral edge, and has relatively low rigidity in the central portion and the central portion. Further, locally, the portion where the dimple 6 is located has higher rigidity than the surroundings, and the portion where the through hole 7 is located is less rigid than the surroundings.

When the bonnet 1 collides with a pedestrian, particularly when the pedestrian collides with a local portion such as the head, the dimples 6 are present even in the relatively low rigidity portion of the central portion of the bonnet. It is also possible that the load may be concentrated on one point at relatively high rigidity. Even in such a case, the load is dispersed and transmitted along the dimple shape (the conical trapezoidal slope), so that the shock absorption amount is large. That is,
The dimple 6 has an effect of mitigating local unevenness of rigidity of the bonnet 1 and avoiding a large difference in injury value even if the collision position is slightly different.

Further, in addition to reducing the weight, the through hole 7 has a hole diameter,
By appropriately adjusting the number, it is possible to adjust the rigidity and establish a compatibility point between the injury value and the entry amount.

The bonnet 1 is a dimple 6 as described above.
Since the through holes 7 are evenly arranged at equal intervals, the injury value and the invasion amount are highly uniform.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second and subsequent embodiments, the same parts as those in the first embodiment are designated by the same reference numerals, and their duplicate description will be omitted.

FIG. 6 (a) is a bottom view of the bonnet 1 of the second embodiment, and FIG. 6 (b) is S of FIG. 6 (a).
It is a -S sectional view.

The second embodiment differs from the first embodiment only in that the second frame portion 5 is provided, and the other structures are the same.

The second frame portion 5 is a frame that extends rearward from the inner panel front portion 31 in the central portion of the bonnet 1, and has a rib shape of a width L1 that projects from the inner panel 3 in the outer panel 2 direction. A gap P is provided between the second frame portion 5 and the outer panel 2.

The central portion of the bonnet is a portion where the bending rigidity tends to be small, but by providing the second frame portion 5, the rigidity of the central portion of the bonnet is supplemented and the rigidity of the entire bonnet is made more uniform. be able to.

Further, due to the gap P between the second frame portion 5 and the outer panel 2, the bonnet 1 in this portion is
After the collision, the deformation of the outer panel 2 reaches the second frame portion 5 at an early stage, and the rigidity increases.

Next, a third embodiment of the present invention will be described with reference to FIG.

FIG. 7 is a bottom view of the bonnet 1 according to the third embodiment. The third embodiment is different from the second embodiment only in that a through hole 7 is not provided and a non-perforated region 9 is provided in a predetermined range shown by a diagonal line around the second frame portion, and the other structures are the same. .

The non-perforated region 9 is set symmetrically along the axis of the second frame portion 5 with a width L2. In the non-perforated region 9, the through holes 7 are not provided even if the through holes 7 are arranged.

Therefore, in the third embodiment, the rigidity of the bonnet central portion is higher than that of the second embodiment, and the rigidity of the bonnet central portion is insufficient even in the second embodiment at the design stage. In this case, by adopting this structure, the rigidity can be supplemented and the rigidity of the entire bonnet can be made more uniform.

Next, a fourth embodiment of the present invention will be described with reference to FIG.

FIG. 8 is a bottom view of the bonnet 1 according to the fourth embodiment.

The width of the second frame portion 51 on the front side is L3,
The width on the rear side is L4, and L4 is set to be larger than L3.

In the fourth embodiment, the second frame portion 5
Only one shape is different from the third embodiment, and the other structures are the same.

As described above, the bending rigidity of the central part of the bonnet tends to be small, but since the bonnet has a shape in which the width dimension is widened to the rear side, the bending rigidity particularly in the rear part of the central part tends to be small.

Therefore, in the fourth embodiment, the rigidity of the rear side of the central portion of the bonnet is made particularly high as compared with the second frame portion having the same width. Therefore, even when the rigidity at the rear of the central portion of the bonnet is insufficient even in the third embodiment at the design stage, the rigidity is compensated by adopting this structure, and the rigidity of the entire bonnet is made more uniform. be able to.

The bonnets of the first to fourth embodiments as described above each have their own characteristics of injury value and penetration amount. The theory and simulation results are shown below.

The injury value (HIC) is defined by the following equation (Equation 1).

[0051]

[Equation 1]

In (Equation 1), assuming that the head of a pedestrian collides with the bonnet, a is a synthetic acceleration of the head at the time of collision (m / s ² ), t is time (ms), t1 and t2. Represents an arbitrary time (ms) in the collision process, and t2>t1>
0 and t2-t1 ≦ 15 ms.

That is, of all the time segments of 15 ms or less in the collision process, the time segment that maximizes the value in the braces on the right side of (Equation 1) is (t1, t2). The value within is defined as the injury value HIC.

The smaller the injury value HIC, the smaller the damage to the pedestrian.

On the other hand, when the injury value HIC is reduced, the deformation amount of the bonnet generally increases and the amount of entry into the vehicle tends to increase. Therefore, it is necessary to formulate a structure that reduces the entry amount while reducing the injury value HIC.

When a certain injury value HIC is fixed, the head synthetic acceleration G (t) that minimizes the amount of entry is theoretically calculated by the following equation (Equation 2).

[0057]

[Equation 2]

(Equation 2) is an expression obtained by assuming that the values in the braces of (Equation 1) are always equal, and the head resultant acceleration G (t) is inversely proportional to the time t raised to the 0.4th power. When set to do so, it indicates that the approach amount becomes the minimum.

The above means that in the bonnet 1, increasing the head synthetic acceleration in the initial stage of the collision and decreasing the head synthetic acceleration in the latter stage of the collision results in minimizing the injury value and the approach amount. ing.

Therefore, it is desirable to have a structure that produces such acceleration while balancing the rigidity, and it is further desirable that there is no particularly large or small portion of rigidity in the surroundings and that the amount of deformation is not biased.

By doing so, it is possible to prevent the injury value from greatly changing even if the collision position is slightly changed.

Further, in view of the engine room layout, if the amount of approach can be adjusted, the degree of freedom in design can be further increased.

FIG. 9 is a simulation result of the injury value and the entry amount.

In FIG. 9, point A, shown in FIG.
The simulation results of the injury value and the entry amount at each point of B are shown. The figure (b) is point A and the figure (c).
Is the result of point B.

In each graph, the vertical axis represents the injury value HIC and the horizontal axis represents the entry amount (mm). T plotted in each
ype-1, 2, 3, 4 are the above-mentioned first, second, third,
This corresponds to each of the fourth embodiments.

In the graph of point A, the damage value and the amount of entry are smaller in type-2 than in type-1, and the effect of the second frame portion 5 is shown. ty
In pe-3 and 4, the injury value is further reduced and the effect is exhibited, while the entry amount is slightly increased.

In the graph of point B, the injury values decrease in the order of type-2, 3, 4 as compared with type-1,
While showing the effect, an increase in the approach volume is also seen.

Such a simulation can be carried out at other points as well, and the final adopted structure can be formulated while considering the injury value and the allowable limit of the approach amount.

In Type-2, 3 and 4, the width dimensions L1, L2, L3 and L4 of the second frame portions 5 and 51 are set.
Since there is a setting element of, the degree of freedom in design is higher.

In addition to the above embodiments, the following (a) to
The embodiment of (e) is also possible.

(A) The arrangement of the dimples 6 may be a polygonal arrangement other than the regular triangular arrangement, another regular arrangement, or a random arrangement.

(B) The arrangement of the through holes 7 may be other regular arrangement or random arrangement.

(C) A structure in which the features of the above embodiments are selectively combined is also possible.

(D) The first frame portion 4 may be entirely joined to the outer panel 2 if necessary.

(E) The second frame portions 5 and 51 may be partially or entirely joined to the outer panel 2 as required.

[0076]

As is apparent from the above description,
According to the invention of claim 1, in a bonnet arranged so as to cover an engine room of a vehicle and mainly composed of an outer panel and an inner panel, the outer panel and the inner panel are substantially closed along an outer peripheral edge of the bonnet. A first frame portion having a cross-sectional shape is formed, the inner panel is formed with a plurality of substantially frustoconical dimples that are recessed from the inner panel toward the back surface of the outer panel, and Since a plurality of through holes are provided around the dimple, the rigidity of the bonnet is improved, and the injury value does not have a large bias regardless of which part of the bonnet the pedestrian hits.

Further, since the inner panel is provided with a plurality of through holes, by adjusting the hole diameter and arrangement,
It becomes easy to optimally design the injury value and the approach amount when a pedestrian collides with the bonnet to have an ideal balance.

According to a second aspect of the present invention, in the bonnet structure according to the first aspect, in the plurality of dimples and the plurality of through holes, in a region where each of them is distributed in at least three or more places, the dimples adjacent to each other have a space between them. It is characterized in that the intervals between adjacent through holes are substantially equal, and the intervals between adjacent through holes are approximately equal, and the intervals between adjacent dimples and through holes are approximately equal, so that the collision sites locally The effect of preventing a large obstacle value can be enhanced.

According to a third aspect of the present invention, in the bonnet structure according to the first or second aspect, the second frame extends from the front portion of the inner panel toward the vehicle rear side in the vehicle width direction central portion of the bonnet. Since the part is formed,
The rigidity of the central part of the bonnet, which tends to be low in rigidity, can be supplemented, and the rigidity of the entire bonnet can be made more uniform.

According to a fourth aspect of the present invention, in the bonnet structure according to the third aspect, since the width dimension of the second frame portion is formed so as to increase toward the rear of the vehicle, the bonnet tends to have low rigidity. The rigidity at the rear of the central part can be supplemented, and the rigidity of the entire bonnet can be made more uniform.

According to a fifth aspect of the present invention, in the bonnet structure according to the third or fourth aspect, in the inner panel, a non-perforated region where the through hole is not provided is provided in a predetermined range around the second frame portion. Therefore, the rigidity of the central portion of the bonnet, which tends to be low in rigidity, can be further supplemented, and the rigidity of the entire bonnet can be made even more uniform.

By properly selecting, combining or tuning the inventions of claims 1 to 5 depending on the size, shape, etc. of the bonnet, light weight, high rigidity and low injury value can be realized, and further injury can be achieved. It is possible to set the value and the approach amount to ideal values.

[Brief description of drawings]

FIG. 1 is a perspective view of a bonnet according to a first embodiment of the present invention.

FIG. 2 is a bottom view of the bonnet according to the first embodiment of the present invention.

3 is a sectional view taken along line QQ of FIG.

FIG. 4 is a sectional view taken along line RR of FIG.

FIG. 5 is a cutaway perspective view showing a part of an outer panel and an inner panel according to the first embodiment of the present invention.

FIG. 6 is a bottom view of the bonnet according to the second embodiment of the present invention.

FIG. 7 is a bottom view of the bonnet according to the third embodiment of the present invention.

FIG. 8 is a bottom view of the bonnet according to the fourth embodiment of the present invention.

FIG. 9 is a simulation result of an injury value and an approach amount according to the first to fourth embodiments of the present invention.

[Explanation of symbols]

1 bonnet 2 outer panel 3 inner panel 4 First frame part 5,51 Second frame part 6 dimples 7 through holes 8 adhesive 9 Non-hole area 31 Inner panel front

Continued front page    (72) Inventor Junichi Kashiwa             2-4-1 Niho, Minami-ku, Hiroshima-shi, Hiroshima Prefecture             Tsuda Sangyo Co., Ltd. F-term (reference) 3D004 AA01 AA04 BA01 CA02

Claims (5)

[Claims] 1. A bonnet arranged to cover an engine compartment of a vehicle and mainly composed of an outer panel and an inner panel, wherein the outer panel and the inner panel have a substantially closed cross-sectional shape along an outer peripheral edge of the bonnet. And a plurality of substantially frustoconical dimples that are recessed from the inner panel toward the back surface of the outer panel are formed on the inner panel, and A vehicle bonnet structure characterized in that a plurality of through holes are provided in the periphery. 2. The plurality of dimples and the plurality of through-holes have a substantially equal spacing between adjacent dimples in a region where they are distributed in at least three or more locations, respectively, The vehicle bonnet structure according to claim 1, wherein the holes are arranged at substantially equal intervals, and the dimples and the through holes which are adjacent to each other are arranged at substantially equal intervals. 3. A second frame portion extending from the front portion of the inner panel toward the vehicle rear side is formed in the vehicle width direction central portion of the bonnet.
Alternatively, the vehicle hood structure described in 2 above. 4. The vehicle bonnet structure according to claim 3, wherein a width dimension of the second frame portion is formed so as to increase toward a vehicle rear side. 5. A predetermined range around the second frame portion,
The vehicle bonnet structure according to claim 3 or 4, further comprising a non-perforated region in which the through hole is not provided.