JP3120658B2 - Car hood structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hood structure of a motor vehicle, and more particularly to a structure for alleviating an impact received in a test in which a head impactor (head impactor) is hit on an upper surface of the hood.

[0002]

2. Description of the Related Art A conventional hood structure of this kind of automobile is shown in FIGS. 17 to 20 (see Japanese Utility Model Application Laid-Open No. 61-26682). FIG. 17 is a perspective view showing a conventional automobile having a hood structure, FIG. 18 is an enlarged view of a main part of FIG. 17, and FIG.
FIG. 5 is a sectional view taken along line V-V of FIG.

[0003] As shown in FIG. 17, an inner panel 7 is provided below the outer panel 3 of the hood 1 (on the engine room 5 side). The inner panel 7 includes a frame 9 and
Inner rib 1 located inside frame 9 to reinforce frame 9
One. Both sides of the frame 9 at the rear of the vehicle body are rotatably supported by the vehicle body via hood hinges 13. The engine 15 is arranged in the engine room 5,
As shown in FIG. 18, a flat plate portion 17 is provided between the inner ribs 11 located above the engine 15. Flat plate part 1
7 is provided with a plurality of cut and raised pieces 19 cut and raised so as to face the engine 15. As shown in FIG. 19, each cut-and-raised piece 19 is formed in a substantially arc-shaped cross section.
Both ends 21 are continuous with the flat plate portion 17.

According to such a hood structure, when the head impactor (head impactor) hits the outer surface of the outer panel 3, the outer panel 3 and the inner rib 11 are deformed so as to protrude toward the engine room 5 and further cut and raised.
9 is pressed against the engine and crushed and deformed. In other words, the amount of energy absorption of the hood 1 above the vehicle body of the engine 15 is increased by cutting and raising the piece 19, and the moving distance of the hood 1 is reduced to secure a necessary amount of energy absorption.

[0005]

However, even if the amount of energy absorbed by the hood 1 is secured in this way, the hood 1
Is not always mitigated.

Experimental data on head impact resistance includes a WSTC (Wayne State Tolerace Curve) shown in FIG.
ve) is known ("Automobile Engineering Handbook <Part 3>" issued by the Japan Society of Automotive Engineers of Japan (September 3, 1983)
(0st edition, first edition), page 2-30, and "Automotive Engineering, Vol. 16, Automobile Safety", published by Sankaido Co., Ltd. (March 20, 1980, first edition, page 201-203).

The effective acceleration used as a parameter of the WSTC is the average acceleration (the integral value of the acceleration waveform divided by the operation time), and corresponds to the average reaction force received by the head impactor at the time of collision. ing.

According to the WSTC, even if the average reaction force received by the head impactor is small to some extent (effective acceleration = G1
), If the duration becomes longer (duration> T1), the danger area is reached, and conversely, even if the average reaction force is large (effective acceleration =
G2), if the duration is extremely short (duration <T2), it does not reach the danger zone and belongs to the safety zone.

That is, head impact resistance is determined by both factors of acceleration and action time. If the amount of energy absorption is large, head impact resistance is not necessarily lowered, and the initial reaction force at impact is reduced. In some cases, a sudden rise to some extent within a predetermined period of time may lower the head impact value than maintain a not so high reaction force for a long time.

Further, WSTC is experimental data under linear acceleration, and the actual impact received when the head impactor (head impactor) collides with the hood 1 shows not a linear acceleration but a complicated acceleration waveform. WST on actual impact
C cannot be applied directly. For this reason, HIC, which is one of the failure reference values, is used as a method for evaluating safety based on the WSTC based on the results of impact experiments using an impactor.
A method using a value (Head Injury Criterion) is known.

The HIC value is calculated by the following equation.

(Equation 1)

(Equation 2) Is calculated according to T1 and t2 in both equations are 0 <t1 <
t2 is an arbitrary time during the acceleration action, and a (t) is the acceleration at the center of gravity of the head of the impactor. As for the HIC value, the smaller the value is, the higher the security is. Generally, HIC = 1000
Is considered a safety limit.

According to the equation, HIC values, the average acceleration a ₁₂ at the working time from any t1 to t2 2.5
It is calculated as the maximum value of the value obtained by multiplying the power value by the operation time (t2-t1). That, HIC value in principle if the impact behavior (acceleration waveform) differences also differ, an average acceleration a ₁₂ and its action time (t2 -t1) is a factor that determines the magnitude of the HIC value. The relationship between the average acceleration a ₁₂ and its action time (t2 -t1) can be replaced with the relationship of the reaction force and the movement distance of the hood 1 of the hood 1, the reaction force of the hood 1 and also by the movement distance , HIC values are determined.

[0013] As a result, the fact that the amount of impact energy absorbed is large does not mean that the HIC value is uniformly reduced, but there are many cases where the HIC value differs even if the energy absorption amount is the same. Further, even if the HIC value at a certain point of the hood 1 becomes a low value, the HIC value may show a high value at another point outside the one point.

Therefore, in the conventional hood structure as shown in FIG. 17, the rise of the crushing reaction force of the cut-and-raised piece 19 formed in a substantially arc-shaped cross section is delayed, and a relatively high reaction force is maintained until a long time has elapsed. In order to reduce the impact on the head, it is necessary to reduce the crush reaction force of the cut-and-raised piece 19 to increase the stroke.

Therefore, the present invention is to reduce the moving distance of the hood to ensure sufficient energy absorption,
It is an object of the present invention to provide a hood structure capable of efficiently lowering the C value and reducing head impact.

[0016]

According to the first aspect of the present invention,
A hood structure of a motor vehicle for absorbing shocks to the outer panel for closing the engine compartment upper surface, said Autapane
A bottom plate provided substantially parallel to the bottom plate, and bending from both sides of the bottom plate.
Bent between opposing side walls and a tip of the side wall
It was allowed to cross each other a plurality of in-<br/> Naribu to deform to absorb the impact has an opening, provided on the lower surface side of the outer panel of the deployed shock interferents above the engine room, the cross In the part, the side walls that cross each other are curved
And at the part deviating from the intersection,
A straight line portion that is straight when viewed from the lower side of the touch panel,
The linear portion is provided with a reinforce for closing the opening and forming a closed cross section in the inner rib.

According to a second aspect of the present invention, there is provided the vehicle hood structure according to the first aspect, wherein the inner rib is line-joined to a lower surface of the outer panel.

[0018] According to a third aspect of the invention, a hood structure of the self <br/> Dosha according to claim 2, said In'naribu, at the periphery of the opening on the lower surface side of the A <br/> Utapaneru Wire joined
And features.

According to a fourth aspect of the present invention, there is provided a hood structure for an automobile according to the third aspect , wherein both side walls of the inner rib are provided.
It is bent in the opposite direction from the tip, and the outer panel
A substantially parallel flange portion is provided, and
A surface is line-bonded to the lower surface of the outer panel.

According to a fifth aspect of the present invention, there is provided an automobile hood structure for absorbing an impact on an outer panel closing an upper surface of an engine room, wherein the inner rib having an opening and absorbing and deforming the impact is provided on the engine. provided arranged shock interferer above the outer panel to the room, is fitted on the surface of the In'naribu, the predetermined reaction force to interfere with the upper surface of the impact interferents prior to In'naribu during deformation subduction of the outer panel Cracked and caused the inner ribs
Characterized in that a hard and brittle member Ru to cause a deformation collapse due to interference between the impact interferer.

According to a sixth aspect of the present invention, there is provided the hood structure for an automobile according to the fifth aspect, wherein the inner rib is allowed to crush and deform the inner rib after the hard brittle member is cracked, thereby reducing the reaction force of the inner rib. It is characterized in that an easy-to-deform portion for reducing is provided.

According to a seventh aspect of the present invention, there is provided the hood structure for an automobile according to the fifth or sixth aspect, wherein a closed cross section is provided in the inner rib.

According to an eighth aspect of the present invention, there is provided an automobile hood structure according to the fifth, sixth or seventh aspect,
A gap between the inner rib and the impact interference body is set to a predetermined interval.

[0024]

According to the first aspect of the present invention, the side wall is removed when the outer panel is submerged and deformed after the outer panel is locally deformed due to the movement of the hood.
A straight line where the secondary reaction force tends to decrease against the intersection because it opens to the side
The secondary reaction force from the inner rib also increases in the portion. Therefore, for a structure where the reaction force of the hood cannot be obtained sufficiently when the outer panel sinks and deforms, the reaction force from the inner rib can be set to an appropriate magnitude, and the relationship between the reaction force of the hood and the travel distance can be determined. An ideal state can be achieved. Thus, the moving distance of the hood can be kept small to ensure sufficient energy absorption, and the HIC value can be efficiently reduced to reduce head impact.

According to the second aspect of the present invention, the first aspect of the present invention is provided.
In addition to the effect of
The inner rib with the closed section
The outer panel at the straight section
The secondary reaction force from the inner rib is
Can be increased.

According to the third aspect of the present invention, the second aspect of the present invention is provided.
Submersion of the outer panel at the straight part of the inner rib
The secondary reaction force from the inner rib is significantly increased during deformation
Can be great.

According to the fourth aspect of the present invention, the second aspect of the present invention is provided.
Submersion of the outer panel at the straight part of the inner rib
The secondary reaction force from the inner rib is significantly increased during deformation
Can be great.

According to the fifth aspect of the present invention , the outer panel is provided on the surface of the inner rib so that the inner panel is formed when the outer panel sinks and deforms.
Since the hard brittle member that breaks by interfering with the upper surface of the impact interference body before the narib is provided, a reaction force due to the rigidity of the hard brittle member is generated before and after the interference of the hard brittle member before and after the outer panel sinks. Further, after the interference of the hard brittle member at the time of sinking of the outer panel, a secondary reaction force is generated when the hard brittle member interferes with the upper surface of the impact interference body,
The hard brittle member is cracked, and a reaction force is generated due to the crush deformation of the inner rib. That is, the reaction force at the time of submerging deformation of the outer panel can be set relatively arbitrarily. Therefore, in the case where the inner rib is caused to interfere with the impact interfering body by suppressing the moving distance of the hood to a small value, the relationship between the reaction force of the hood and the moving distance can be set to an ideal state, while securing sufficient energy absorption. , HIC value can be efficiently reduced, and head impact can be reduced.

According to the sixth aspect of the present invention, since the easily deformable portion is provided on the inner rib, the reaction force due to the crushing deformation of the inner rib after the hard brittle member is broken can be arbitrarily set. That is, the reaction force can be arbitrarily set for a structure in which the reaction force due to the crushing deformation of the inner rib after the hard brittle member is cracked is too large. Therefore, in a case where the inner rib interferes with the impact interfering body while keeping the movement distance of the hood small, the relationship between the reaction force of the hood and the movement distance can be made more ideal, and sufficient energy absorption can be secured. At the same time, the head impact can be reduced by effectively lowering the HIC value.

According to the seventh aspect of the present invention, since the closed cross section is provided in the inner rib, it is possible to more reliably obtain the reaction force of the hard brittle member before the hard brittle member interferes with the impact interference body. That is, the reaction force can be reliably increased for a structure in which the reaction force of the hard brittle member is small before the hard brittle member interferes with the impact interference body. Therefore, in the case where the inner rib interferes with the impact interfering body while keeping the movement distance of the hood small, the relationship between the reaction force of the hood and the movement distance can be more reliably set in an ideal state, and a sufficient energy absorption amount can be obtained. As well as H
The IC value can be efficiently reduced, and the head impact can be reduced.

In the eighth aspect of the present invention, since the gap between the inner rib and the impact interference body is set to a predetermined distance, the moving distance of the hood until the hard brittle member interferes with the impact interference body is uniform, and the hard brittle member is The reaction force from the hard brittle member and the inner rib after interfering with the impact interference body can be obtained with an optimum moving distance. That is, for a structure in which the distance between the outer panel and the impact interfering body is changed, a reaction force after the hard brittle member interferes with the impact interfering body can be obtained with an optimum moving distance. Therefore, when the inner rib interferes with the impact interfering body by suppressing the moving distance of the hood to a small value, the relationship between the reaction force of the hood and the moving distance can be made more ideal, and a sufficient amount of energy absorption can be secured. At the same time, the HIC value can be efficiently reduced, and the head impact can be reduced.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments according to the present invention will be described with respect to each position of a hood of an automobile whose travel distance is limited.
By adopting a structure for efficiently lowering the C value, head impact resistance is reduced.

Specifically, the moving distance of the hood and the HIC
The waveform (ideal waveform) indicating the ideal relationship between the reaction force of the hood and the amount of movement of the hood, which can keep both values small, is calculated based on the amount of energy absorption required at the time of impact and the derivation formula (1).
By calculating in advance based on (2) and performing an impact experiment at a predetermined position of the hood to determine the actual reaction force waveform (basic waveform), the hood structure is such that the basic waveform approaches the ideal waveform. The HIC value is efficiently and reliably reduced with a small moving distance. The effective structure for bringing the basic waveform closer to the ideal waveform depends on various conditions such as the shape of the basic waveform, the hood structure (foundation structure) on which the experiment was performed, and the allowable moving distance of the hood. Thus, each embodiment of the present invention shows an effective structure under different conditions.

Hereinafter, a first embodiment according to claims 1 and 2 of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a main part of a hood structure of an automobile according to a first embodiment, and FIG.
FIG. 3 is a cross-sectional view, and FIG. 3 shows a hood structure (basic structure) as a basis of the present embodiment in the same cross section as FIG.

As shown in FIG. 1, an outer panel 33 of the hood 31 closes an upper surface of an engine room 35, and an inner panel 37 is provided on a lower surface 33a of the outer panel 33 which is a lower side of the vehicle body (the engine room 35 side). I have. The inner panel 37 has a plurality of inner ribs 39 having a hat-shaped cross section that project downward from the vehicle body, intersect with each other, and absorb and deform the impact on the outer panel 33. Each inner rib 3
9 is a bottom plate 4 provided substantially parallel to the outer panel 33.
1, a side wall 43 bent from both sides of the bottom plate 41 to the outer panel 33 side, and an opening 44 formed between the front ends of the side walls 43, and substantially parallel to the outer panel 33 and opposed from the front ends of the side walls 43. It has a flange part 45 bent in the direction. At the crossing portion 47 where the inner ribs 39 cross each other, each bottom plate 41 and the flange portion 45 are formed on the same surface so as to be continuous with the bottom plate 41 and the flange portion 45 crossing the bottom plate 41 and the flange portion 45, and the side wall 43a of the crossing portion 47 is curved. Is formed. Intersection 47 of inner rib 39
A straight portion 49 that is linear when viewed from the lower surface 33a side of the outer panel 33 is provided in a portion deviated from the outer panel 33. That is, the side wall 43b of the straight portion 49 is
Are substantially linearly extended when viewed from the lower surface 33a side.

The straight portion 49 of the inner panel 37 is connected to the upper surface 45a of the flange portion 45 and
A flat reinforcement 51 forming a closed cross section N is provided in the inner rib 39 between the three. Flange part 4
5 and the upper surfaces 45a, 51a of the reinforcement 51 are attached to the lower surface 33a of the outer panel 33 at predetermined intervals.
Thus, the inner rib 39 is joined to the outer panel 33. As the resin 57, an elastic mastic sealer or the like is used.

Further, as shown in FIG.
An engine 53 as an impact interferer is disposed in a central portion of the inside. The inner rib 39 is separated from the upper surface 53a of the engine 53 so as not to interfere with the engine 53 after the deformation due to the shock absorption. The distance L1 between the upper surface 53a of the engine 53 and the lower surface 39b of the inner rib 39 is the ideal waveform Cm shown in FIG. Is set to be longer than the moving distance S0.

Next, the operation will be described.

In this embodiment, the inner rib 39 is connected to the engine 5
In order to reduce the impact of the head of the hood 31 immediately above the inner rib 39 without interfering with the inner rib 39, the HIC value is reduced at such a position. In this structure, a waveform similar to the ideal waveform (reaction force (F) of the hood-moving distance due to the deformation of the hood) that can be reduced to a minimum value can be obtained.

FIG. 3 shows the basic structure on which the impact test was performed.
FIG. 4 shows the basic waveforms C1 and C2 and the ideal waveform Cm obtained as a result of the impact experiment.

The hood 59 of the basic structure as shown in FIG. 3 has substantially the same structure as that of FIGS. 1 and 2 except that the reinforcement 51 is not provided.
are bonded to the lower surface 33a of the outer panel 33 by a resin 57 at predetermined intervals.

In the impact test on the basic structure, the impactor 55 was applied to the upper side of the crossing portion 47 (position P in the drawing) and the upper side of the linear portion 49 (position Q in the drawing) of the inner rib 39, and the moving distance of the impactor 55 And by measuring the acceleration. The moving distance and acceleration of the impactor 55 correspond to the moving distance (moving distance of the outer panel 33) due to the deformation of the hood 59 shown on the horizontal axis in the figure and the reaction force of the hood 59 shown on the vertical axis in the figure, respectively. Thus, the basic waveform C1 shown in FIG.
C2 is obtained. In the figure, the basic waveforms C1 and C2 have a schematic shape, and the dashed line indicates the basic waveform C
1 and the dotted line shows the basic waveform C2 at the Q position.

The ideal waveform Cm is an ideal reaction force waveform that can suppress both the moving amount of the hood 59 and the HIC value in the basic structure, and the energy absorption amount required at the time of impact and the formula for deriving the HIC. Is obtained by calculation based on. The internal area A1 defined by the ideal waveform Cm and the moving distance S on the horizontal axis in the drawing is the absorbed energy U, and the internal area A1 is set so as to have the required amount of energy absorption. The energy absorption required at the time of impact is obtained by an impact experiment, calculation, or the like.

In the ideal waveform Cm, the initial reaction force suddenly increases in the initial stage of deformation where the moving distance S is small, reaches the maximum reaction force F1 at the moving distance S1 (p _{m in the} figure), and becomes the reaction force during the moving distance S2. Although but decreases rapidly to F2, the deformation late after moving distance S2, shoulder secondary reaction force is relaxed the proportion of the reaction force decrease acts (figure q _m) is manifested, further movement distance S3 Then, the reaction force suddenly decreases again, and at the moving distance S0, the impact energy is completely absorbed, and the reaction force reaches almost zero.

In the basic waveform C 1 at the position P, the outer panel 33 locally deforms along the outer shape of the impactor 55 in the initial stage of the deformation immediately after the collision, and mainly the outer panel 33
The initial reaction force, which depends on the tension of
There maximum reaction force (approximately F1) is obtained in a state where a substantially S1 (figure p _1). After obtaining the maximum reaction force, the outer panel 33
Starts sinking in a wide range due to the inertial force received from the impactor 55, and the reaction force F suddenly decreases as the moving distance S increases, and the moving distance S reaches approximately S2, and the reaction force substantially decreases. It drops to F2. Deformation late after moving distance S2 is generated secondary reaction force starts to deform collapse large In'naribu 39, shoulder portions reduction rate of the reaction force F is relieved (in the figure q ₁₎
Appears. And when the inner rib 39 is sufficiently crushed,
The impact energy is completely absorbed before the inner rib 39 interferes with the engine 53, and the reaction force F sharply decreases again to almost zero. Thus, at the P position, the ideal waveform C
A waveform similar to m is obtained.

On the other hand, the basic waveform C2 at the Q position indicates that the initial reaction force by the outer panel 33 suddenly increases immediately after the collision to reach the maximum reaction force (approximately F1), and then the reaction force F decreases until the reaction force F suddenly decreases. It is almost the same as the basic waveform C1, and is close to the ideal waveform Cm.

However, in the basic waveform C2, when the outer panel 33 sinks in the latter stage of the deformation, the reaction force F becomes F2.
After that, the reaction force further decreases, and the rate of decrease of the reaction force F is alleviated thereafter, which greatly differs from the ideal waveform Cm. That is, basic waveform C2 is a shoulder portion (in the figure q ₂₎ is in the lower than the ideal waveform Cm.

The reason why such a difference occurs between the P position and the Q position is that the deformation state of the side wall 43 when the outer panel 33 sinks in both positions is different.
That is, at the P position, the intersecting side walls 43 are curved, so that the side walls 43 do not open outward due to the deformation at the time of impact, and the inner ribs 39 are securely crushed and deformed, so that a high secondary reaction force is obtained. . On the other hand, in the Q position, the inner panel 37
Since the side wall 43 is formed linearly, the side wall 43 is opened outward and crushing deformation is insufficient, and the secondary reaction force is reduced.

When the secondary reaction force is insufficient and the shoulder portion is lower than the ideal waveform Cm, the internal area of the basic waveform C2 becomes small and sufficient absorption energy cannot be secured. 39a is the engine 53
The inner ribs 39 are crushed and deformed by hitting the upper surface 53a of the, and as a result, absorbed energy is secured. Therefore, the reaction force F after a long time has passed since the start of the impact
Rises (r2 in the figure).

On the other hand, the hood 31 according to the present embodiment
Since the closed section N is formed by providing the linear portion 49 of the inner rib 39 with the reinforcement 51 as shown in FIG. 2, the side wall 43b does not open outward due to the deformation of the hood 31 in the linear portion 49. Then, the inner rib 39 is reliably crushed and deformed. As a result, a secondary reaction force of a desired size is generated, and a shoulder portion of an appropriate size appears, the inner rib 39 is sufficiently crushed, and the impact energy is completely absorbed before the inner rib 39 interferes with the engine 53. Thus, a waveform approximating the ideal waveform Cm is obtained.

That is, when an impact experiment is performed on the linear portion 49 (the Q position) of the hood 31 according to the present embodiment, the outer panel 33 initially undergoes local deformation along the outer shape of the impactor 55 in the initial stage of deformation. Reaction force increases sharply and travel distance S is almost
In the state of S1 , a maximum reaction force (approximately F1) is obtained. After obtaining the maximum reaction force, the outer panel 33 starts sinking in a wide range due to the inertial force received from the impactor 55, and the reaction force F Suddenly decreases, and when the moving distance S reaches approximately S2, the reaction force decreases to approximately F2. Thereafter, the inner rib 39 is greatly collapsed and starts to be deformed by the action of the reinforce 51.
When the desired secondary reaction force occurs and an accurate shoulder portion appears, and the inner rib 39 is sufficiently crushed, the impact energy is completely absorbed before the inner rib 39 interferes with the engine 53, and the reaction force F sharply decreases again. And it becomes almost zero. Therefore, according to the present embodiment, a waveform similar to the ideal waveform Cm can be obtained, and the HIC value can be effectively reduced with a short moving distance, and the head impact can be reduced.

On the other hand, regarding the crossing portion 47 (P position),
Since it has the same configuration as the hood 59 relating to the basic structure,
A waveform similar to the ideal waveform Cm is obtained.

As described above, in the present embodiment, the inner rib 39
Above the portion where the side wall 43a of the inner panel 37 is curved, such as the crossover portion 47, the ideal waveform Cm
And a low HIC value can be obtained.
9, the secondary reaction force is low and the shoulder portion (q in FIG. 4)
₂ ) With respect to the structure having a low level, only the secondary reaction force can be accurately increased to obtain a waveform similar to the ideal waveform Cm, and the head impact at an arbitrary position above the inner rib 39 can be reduced. Can be achieved.

Next, a second embodiment according to claims 1, 3 and 4 of the present invention will be described with reference to the drawings.

In this embodiment, the inner rib 39 is connected to the engine 5
The third embodiment is similar to the first embodiment in that the head impact immediately above the inner rib 39 is alleviated without causing interference with the inner rib 39, but is different from the first embodiment in that the secondary reaction force is greatly increased. Is what you do.

FIG. 5 is a perspective view showing a main part of the hood structure of the automobile according to the present embodiment, FIG. 6 is a sectional view taken along the line II of FIG. 5, and FIG. FIG. 7 shows the structure (basic structure) in the same cross section as FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 5 and 6, the hood 61 according to this embodiment includes a flange 45 which is a peripheral edge of the opening 44.
Is bonded to the lower surface 33a of the outer panel 33 by a resin 63, and the inner rib 39 is wire-bonded to the outer panel 33, thereby forming the inner rib 39.
A closed section N is provided therein. As the resin 63, an elastic mastic sealer or the like is used as in the first embodiment.

Further, an engine 53 as an impact interference body is arranged in a central portion in the engine room 35.
After the inner rib 39 is deformed due to shock absorption, the engine 5
The distance L1 between the upper surface 53a of the engine 53 and the lower surface 39b of the inner rib 39 is set to be equal to the ideal waveform Cm shown in FIG.
Is set to be longer than the moving distance S0.

Next, the operation will be described.

The hood 61 according to the present embodiment has a structure similar to the first embodiment, in which a waveform similar to an ideal waveform can be obtained in an impact test.

FIG. 7 shows a basic structure on which an impact test was performed.
FIG. 8 shows a basic waveform C3 and an ideal waveform Cm obtained as a result of the impact test.

As shown in FIG. 7, the hood 62 of the basic structure is the same in structure as the basic structure of the first embodiment, but the structures and materials of the outer panel 33 and the inner panel 37, and the materials and dimensions of the inner rib 39. Because the shape etc. are different, the first
The result of the impact test performed in the same manner as in the embodiment is different. As a result of the impact test, a basic waveform C3 indicated by a chain line in FIG. 8 is obtained. In the figure, the basic waveform C3 has a schematic shape, and the ideal waveform Cm is the same as in the first embodiment.

[0064] In basic waveform C3, after reached the maximum reaction force initial resistance by the outer panel 33 to deform the initial stage with rapid increase (figure p _3), to the point where the reaction force F decreases suddenly, the ideal waveform Cm Is approximated.

However, in the basic waveform C3, even after the reaction force F becomes F2 in the later stage of the deformation, the reaction force further decreases, and thereafter the reaction force F becomes almost zero without being relaxed. In this point, it is greatly different from the ideal waveform Cm. That is, basic waveform C3, the secondary reaction force hardly appears shoulder portion was hardly obtained (figure q ₃₎ it is seen. This is because a sufficient absorption energy inside area smaller basal waveform C3 is not secured, the inner Li by striking the upper surface 53a of the engine 53
The bump 39 is crushed and deformed (r _{3 in the} figure), and as a result, absorbed energy is secured. For this reason, the reaction force F increases after a long time has elapsed from the start of the impact (r _{3 in the} figure).

Such a difference is caused by the fact that the inner rib 39 does not follow the outer panel 33 which is greatly deformed in the later stage of the deformation in the hood 62 having the basic structure, and the inner rib 39 is hardly crushed and deformed. I have.

On the other hand, the hood 61 according to this embodiment
Since the inner rib 39 is linearly joined to the outer panel 33 to form a closed section N in the inner rib 39 as shown in FIG.
The inner rib 39 does not open outward but the outer panel 3
Following the large deformation of No. 3, the same deformation as that of the outer panel 33 also occurs in the inner rib 39, and the inner rib 39 is reliably crushed and deformed. As a result, a secondary reaction force of a desired size is generated, a shoulder portion of an appropriate size appears, the inner rib 39 is sufficiently crushed, and the inner rib 39 is connected to the engine 5.
The impact energy is completely absorbed before interfering with No. 3, and a waveform approximating the ideal waveform Cm is obtained.

That is, when an impact experiment is performed on the hood 61 according to the present embodiment, the outer panel 33 is initially deformed.
Caused a local deformation along the outer shape of the impactor 55, the initial reaction force increased rapidly, and the maximum reaction force (approximately F1) was obtained when the moving distance S was approximately S1, and the maximum reaction force was obtained. Thereafter, the outer panel 33 starts sinking in a wide range due to the inertial force received from the impactor 55, and the reaction force F suddenly decreases. When the moving distance S reaches approximately S2, the reaction force decreases to approximately F2. Thereafter, the inner rib 39 is largely collapsed and deformed by the action of the wire joining, and a desired secondary reaction force is generated, and an accurate shoulder portion appears. When the inner rib 39 is sufficiently collapsed, the inner rib 39 interferes with the engine 53. Before the impact energy is completely absorbed, the reaction force F sharply decreases again and becomes almost zero. Therefore, according to the present embodiment, a waveform similar to the ideal waveform Cm can be obtained as in the first embodiment, and the HIC value can be effectively reduced with a short moving distance, and the head impact can be reduced. it can.

As described above, in the present embodiment, on the upper side of the inner rib 39 where the gap with the engine 53 is relatively large,
For a structure in which the secondary reaction force is smaller than that of the first embodiment and the shoulder portion (qm in FIG. 8) hardly appears, a waveform approximate to the ideal waveform Cm by appropriately increasing the secondary reaction force. Can be obtained, and the impact on the head above the inner rib 39 can be reduced.

The inner rib 39 is connected to the outer panel 33.
When the secondary reaction force at the crossing portion 47 is sufficient in the state where the secondary reaction force at the intersection portion 47 is insufficient, but when the secondary reaction force at the linear portion 49 is insufficient, the inner rib 39 is attached to the inner rib 39 similarly to the first embodiment. By providing the reinforcement 51 and further connecting the wire to the outer panel 33, only the secondary reaction force can be accurately increased, and a waveform similar to the ideal waveform Cm can be obtained. Can be alleviated.

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

This embodiment is the same as the first embodiment in that the impact on the head immediately above the inner rib 39 is reduced, but the secondary reaction force is increased by causing the inner rib 39 to interfere with the engine 53. This is a difference.

FIG. 9 is a plan view showing the hood structure of the automobile according to this embodiment, FIG. 10 is a JJ sectional view of the hood of FIG. 9, FIG. 11 is a KK sectional view of FIG. Shows a hood structure (basic structure) which is the basis of the present embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS . 9 to 11 , the hood 65 according to the present embodiment relates to the inner rib 39a of the inner rib 39 which extends linearly above the engine 53, and covers the surface of the inner rib 39a. Hard brittle member 67 is provided. The hard brittle member 67 increases the reaction force of the inner rib 39 in the initial stage of the deformation of the outer panel 33, and is made of a hard and easily cracked material such as a hardened resin or a hardened resin coated with a thin metal film. The hardened brittle member 67 is formed in a hat-shaped cross section along the outer surface of the inner rib 39a, and is externally attached to and bonded to the inner rib 39a. The end 67 a of the hardened brittle member 67 on the outer panel 33 side is adhered to the outer panel 33.

In the side wall 43 of the inner rib 39a, a plurality of holes 69 are formed as easily deformable portions. The hole 69 has a long hole shape extending in the up-down direction of the vehicle body, and the side wall 43 is easily crushed and deformed by the hole 69, and the crushing reaction force of the side wall 43 itself is reduced. That is, the crush reaction force of the side wall 43 itself can be set to a desired size by the number, shape, and size of the holes 69.

The upper surface of the flange portion 45 is
3 is bonded to the lower surface of the inner rib 3 by a resin 63.
9, a closed section N is provided. As the resin 63, an elastic mastic or the like is used as in the first embodiment.

The lower surface 67 b of the hard brittle member 67 is provided at a position where the lower surface 67 b interferes with the upper surface 53 a of the engine 53 at a later stage of the deformation of the outer panel 33. That is, the inner rib 3
The distance L2 between the upper surface 53a of the engine 53 and the lower surface 67b of the hard brittle member 67, which is the gap between the engine 9a and the engine 53
Is set to a predetermined distance smaller than the moving distance S0 of the ideal waveform Cm shown in FIG. When the hard brittle member 67 interferes with the upper surface 53 a of the engine 53, it generates a predetermined reaction force and breaks. Further, when the hard brittle member 67 is cracked, the inner rib 39a undergoes large crushing deformation due to interference with the engine 53.

Next, the operation will be described.

The hood 65 according to the present embodiment has a structure similar to the first embodiment, in which a waveform similar to an ideal waveform can be obtained in an impact test.

FIG. 12 shows a basic structure in which an impact test was performed, and FIG. 13 shows a basic waveform C4 and an ideal waveform Cm obtained as a result of the impact test.

As shown in FIG. 12, the hood 66 having the basic structure
The basic structure of the first embodiment is the same as that of the first embodiment, but the structures and materials of the outer panel 33 and the inner panel 37 and the inner rib 3
9a material, size and shape, and lower surface 3 of inner rib 39a
9b and the distance L3 between the upper surface 53a of the engine 53 and the like are different (L3> L2). Therefore, the result of the impact test is different as in the first embodiment.
A basic waveform C4 indicated by a chain line in FIG. 13 is obtained. In the figure, the basic waveform C4 has a rough shape,
m is the same as in the first embodiment.

The basic waveform C4 is different from the ideal waveform Cm in that
Mainly initial resistance is generally somewhat lower that depends on the outer panel 33, it is also low reaction force F4 at the maximum reaction force F3 (figure P ₄₎ and deformation late. Further, in the modified later, a slight increase reaction force F undergoes In'naribu 39a gradually deformed (figure h _4), In'naribu 39a is the reaction force F is rapidly deforms crushed interfere with engine 53 (in the figure r ₄ ) is significantly different from the ideal waveform Cm. That is, in the hood 62 of the basic structure, the initial reaction force is slightly low, the drop of the reaction force F in the late stage of deformation is large, no shoulder (q _{m in the} figure) is generated, and the interference with the engine 53 is slow. reaction force F when the moving distance S becomes S0 or more is rapidly increasing (figure r ₄₎ it is seen. In this case, the reaction force F increases after a long time has elapsed from the start of the impact (r _{4 in the} figure).

On the other hand, the hood 65 according to the present embodiment
Is provided with a hard brittle member 67 so as to cover the surface of the inner rib 39a as shown in FIGS. 10 and 11.
When the outer panel 33 sinks in the initial stage of deformation, the hard brittle member 67 suppresses the sink amount of the outer panel 33, and can obtain an initial reaction force higher than that of the base structure. At this time, since the inner rib 39a is linearly joined to the outer panel 33, the amount of sinking of the outer panel 33 is more reliably suppressed.

When the hard brittle member 67 interferes with the upper surface 53a of the engine 53, a secondary reaction force is generated at the time of the interference, and thereafter, the hard brittle member 67 is broken as shown in FIG. Deformation occurs and the secondary reaction force decreases. At this time, since the gap between the inner rib 39a and the engine 53 is set to a predetermined distance L2,
The secondary reaction force can be obtained from the same moving distance S2 as the ideal waveform, and the crushing reaction force of the inner rib 39a itself is equal to the hole 69.
, The secondary reaction force can be accurately reduced.

That is, when an impact experiment is performed on the hood 65 according to the present embodiment, in the initial stage of deformation, the outer panel 33 locally deforms along the outer shape of the impactor 55, the initial reaction force rises, and the hard brittleness increases. The maximum reaction force (substantially F1) is obtained in a state where the initial reaction force is entirely increased by the member 67, the initial reaction force is rapidly increased, and the moving distance S is substantially equal to S1, and after the maximum reaction force is obtained. , The outer panel 33 is the impactor 5
Due to the inertial force received from 5, sinking starts in a wide range and the reaction force F suddenly decreases, and the moving distance S reaches approximately S2 and decreases until the reaction force becomes approximately F2. When the moving distance S reaches approximately S2, the hard brittle member 67 is moved to the upper surface 53 of the engine 53.
a and a secondary reaction force is generated. Then, the hard brittle member 67 is cracked, the inner rib 39a undergoes a large crushing deformation, and the secondary reaction force is reduced. As a result, a desired secondary reaction force is generated and an accurate shoulder portion appears. Further, when the inner rib 39 is sufficiently crushed, the impact energy is completely absorbed, and the reaction force F sharply decreases again to almost zero. . Therefore, according to the present embodiment, a waveform similar to the ideal waveform Cm can be obtained as in the first embodiment, and the HIC can be obtained with a small moving distance.
The value can be effectively reduced to reduce head impact.

As described above, according to the present embodiment, since the initial reaction force is slightly lower and the secondary reaction force is extremely low above the inner rib 39a having a relatively small gap with the engine 53, the shoulder portion (see FIG. 8, a waveform similar to the ideal waveform Cm can be obtained for a structure in which q _m ) hardly appears, and the impact on the head above the inner rib 39 can be reduced.

In this embodiment, the inner rib 39a having a substantially rectangular cross section has been described. However, as shown in FIGS. 15A and 15B , the cross section is trapezoidal or triangular. With respect to the inner rib 39a, the same effect as described above can be obtained by providing the hard brittle member 67 in accordance with the shape of the inner rib 39a.

Further, even when the distance between the outer panel 33 and the engine 53 changes as in the hood 73 shown in FIG. 16, the distance between the upper surface 53a of the engine 53 and the lower surface 67b of the hard brittle member 67 can be improved. By forming the inner rib 39a so that the distance L4 is a predetermined distance, the same effect as described above can be obtained.

[0089]

As described above, according to the first aspect of the present invention, the movement distance of the hood can be reduced to a structure in which a sufficient reaction force cannot be obtained from the inner rib when the outer panel sinks. Sufficient energy absorption can be ensured and the head impact can be reduced.

According to the second aspect of the present invention, the moving distance of the hood can be reduced without causing the inner rib to interfere with the impact interfering member, in a structure having a straight portion of the inner rib having a small reaction force when the outer panel sinks. It is possible to ensure sufficient energy absorption by keeping the energy level small and to reduce head impact.

According to the third aspect of the present invention, it is possible to prevent the inner rib from interfering with the impact interfering member in a structure in which the reaction force when the outer panel sinks and deforms is extremely small.
The moving distance of the hood can be kept small, sufficient energy absorption can be ensured, and head impact can be reduced.

According to the fourth aspect of the present invention, in a structure having a straight portion of the inner rib and having a very small reaction force when the outer panel sinks and deforms, the inner rib does not interfere with the impact interference body. The moving distance of the hood can be kept small, sufficient energy absorption can be ensured, and head impact can be reduced.

According to the fifth aspect of the present invention, when the inner rib interferes with the impact interfering body, the relationship between the reaction force of the hood and the moving distance can be made ideal, and the moving distance of the hood can be reduced. It is possible to ensure sufficient energy absorption by keeping the energy level small and to reduce head impact.

According to the sixth aspect of the present invention, when the inner rib interferes with the impact interfering element, the moving distance of the hood is larger than the structure in which the reaction force due to the crush deformation of the inner rib after the hard brittle member is cracked is too large. And a sufficient energy absorption can be ensured, and the head impact can be reduced.

According to the seventh aspect of the present invention, when the inner rib interferes with the impact interfering body, the hood moves with respect to the structure in which the reaction force of the hard brittle member before the interference with the impact interfering body is small. The distance can be kept small, sufficient energy absorption can be ensured, and head impact can be reduced.

According to the eighth aspect of the present invention, when the inner rib interferes with the impact interfering element, the moving distance of the hood can be suppressed to be small compared to the structure in which the distance between the outer panel and the impact interfering element is changed. Energy absorption and head impact can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a hood structure of an automobile according to a first embodiment.

FIG. 2 is an HH sectional view of the hood of FIG.

FIG. 3 is a sectional view showing a basic structure of the first embodiment.

FIG. 4 shows basic waveforms C1 and C2 and an ideal waveform C of the first embodiment.
It is a schematic diagram which shows m.

FIG. 5 is a perspective view showing a main part of a hood structure of an automobile according to a second embodiment.

FIG. 6 is a sectional view taken along line II of the hood of FIG. 5;

FIG. 7 is a sectional view showing a basic structure of a second embodiment.

FIG. 8 is a schematic diagram showing a basic waveform C3 and an ideal waveform Cm of the second embodiment.

FIG. 9 is a plan view showing a hood structure of an automobile according to a third embodiment.

FIG. 10 is a sectional view of the hood of FIG. 9 taken along the line JJ.

FIG. 11 is a sectional view taken along the line KK of FIG. 9;

FIG. 12 is a sectional view showing a basic structure of a third embodiment.

FIG. 13 is a schematic diagram showing a basic waveform C4 and an ideal waveform Cm of the third embodiment.

FIG. 14 is a sectional view showing the operation of the third embodiment.

15A and 15B are cross-sectional views showing another inner rib of the third embodiment, in which FIG. 15A shows a trapezoidal cross section, and FIG. 15B shows a triangular cross section.

FIG. 16 is a perspective view showing a hood structure in which a distance between an outer panel and an engine is changed.

FIG. 17 is a perspective view showing an automobile having a conventional hood structure.

FIG. 18 is an enlarged view of a main part of FIG. 17;

FIG. 19 is a sectional view taken along line VV of FIG. 18;

FIG. 20 is a diagram showing a WSTC.

[Explanation of symbols]

 31 Hood 33 Outer Panel 33a Lower Surface of Outer Panel 35 Engine Room 39 Inner Rib 39a Inner Rib 44 Opening 49 Straight Line 51 Reinforce 53 Engine (Impact Interference Body) 61 Hood 67 Hard Brittle Member 69 Hole N Closed Section

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 25/10

Claims (8)

(57) [Claims] 1. A hood structure of an automobile for absorbing an impact on an outer panel closing an upper surface of an engine room, comprising: a bottom plate provided substantially in parallel with the outer panel;
Opposing side walls bent from both sides of the plate;
A plurality of inner ribs having an opening formed between the ends and absorbing and deforming the impact are intersected with each other , and are provided on the lower surface side of the outer panel above the impact interfering body arranged in the engine room, and In the part, the side walls that cross each other are formed in a curved shape
And the outer pad
A straight line portion that is straight when viewed from the lower surface side of the panel;
A hood structure for an automobile, wherein a reinforce that closes the opening and forms a closed cross section in the inner rib is provided in the line portion . 2. The vehicle hood structure according to claim 1 , wherein said inner rib is wire-bonded to a lower surface of said outer panel.
Automobile hood structure, characterized in that it was. 3. A hood structure for an automobile according to claim 2 , wherein said inner rib is line-joined to a lower surface of said outer panel at a periphery of said opening. 4. The hood structure for an automobile according to claim 3 , wherein said inner ribs are bent in opposite directions from ends of both side walls.
And a flange portion extending substantially parallel to the outer panel.
And an upper surface of the flange portion is linearly joined to a lower surface side of the outer panel. 5. An automobile hood structure for absorbing an impact on an outer panel closing an upper surface of an engine room, wherein an inner rib having an opening and absorbing and deforming the impact is disposed in the engine room. provided interferer above the outer panel, are fitted on the surface of the In'naribu, broken by generating a predetermined reaction force to interfere with the upper surface of the impact interferents during ahead In'naribu deformation sinking of the outer panel, Inn
Collapse of Narib caused by interference with the impact interfering body
Automobile hood structure characterized in that a hard and brittle member Ru is. 6. The hood structure of an automobile according to claim 5, wherein the inner rib is provided with an easily deformable portion for reducing a reaction force of the inner rib by allowing the inner rib to crush and deform after the hard brittle member is cracked. A hood structure for an automobile characterized by being provided. 7. The hood structure of an automobile according to claim 5, wherein a closed cross section is provided in the inner rib. 8. The hood structure for an automobile according to claim 5, wherein the gap between the inner rib and the impact interference body is a predetermined distance. .