JPH0880873A - Car hood - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress the inversion behavior of the stepped portion and to effectively mitigate the impact. An inner panel 11 is provided on the back surface of an outer panel 3 having a convex flat surface portion 7 and a concave flat surface portion 9 divided by a step portion 5, and the outer panel 3 and the inner panel 11 are provided.
In the meantime, while being supported by the inner panel 11 and supporting the vicinity of the step portion 5 of the convex-side flat surface portion 7 from the back surface, when the moving distance of the hood 1 reaches a predetermined size, it is crushed and deformed to generate a desired reaction force. The shock absorber 21 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile hood which absorbs an impact received by an outer panel.

[0002]

2. Description of the Related Art As a conventional automobile hood of this type,
As shown in FIG. 10, a hood 101 composed of an outer panel 103 and an inner panel 105 as a reinforcing material for the outer panel 103 is known. The inner panel 105 is provided on the back surface of the outer panel 103, forms the skeleton of the hood 101, and secures the rigidity of the hood 101. As shown in FIG. 11, the cross-sectional shape of the inner panel 105 is a hat-shaped cross-section that opens toward the outer panel 103, and the flange portion 105 a of the inner panel 105,
The outer panels 103 are adhered to each other 105b to form a closed section 107. Like this hood 101
Is reinforced by the closed cross section 107 formed by the outer panel 103 and the inner panel 105, and deformation of the hood 101 due to wind pressure or the like is prevented.

As shown in FIG. 12 (a), when an impact force P is applied to the outer surface of the outer panel 103 by the head impactor H, the outer panel 103 first responds to the deformation velocity in the impact direction with the transverse wave propagation velocity of the plate. However, the surface tends to locally extend downward, but as shown in FIG. 7B, a strong surface tension in the radial direction is generated in the outer panel 103 to disperse the force, which causes a wide range. As it attempts to deform, the effective mass becomes large and a large initial reaction force is generated. After the initial reaction force is generated, the outer panel 10
3 starts to deform in a wide range, and a secondary reaction force is generated by the inner panel (not shown) provided on the back surface of the outer panel 103.

FIG. 19 shows the reaction force characteristic which is the relationship between the movement distance of the hood and the reaction force. The reaction force characteristic waveform (C0) of the hood 101 is shown by the dotted line in the figure. According to the hood 101, an appropriate initial reaction force and secondary reaction force can be obtained, the movement amount of the hood 101 can be suppressed to be small, and a sufficient energy absorption amount can be secured.

[0005]

As shown in FIG. 13, a step portion 109 is provided on the outer panel 103 in the hood of an automobile, and the outer panel 10 is formed by the step portion 109.
3 is divided into a convex side flat surface portion 111 and a concave side flat surface portion 113. The step portion 109 extends in the vehicle body front-rear direction on both sides of the vehicle width, and has a convex side flat surface portion 111 and a concave side flat surface portion 1.
The line between No. 13 and 13 is a gentle slope and forms a so-called character line in appearance.

In the outer panel 103 having such a step portion 109, as shown in FIG. 14A, when a shock is applied to the convex side flat surface portion 111 in the vicinity of the step portion 109,
Since the step portion 109 is allowed to expand when deformed, the load is concentrated, and as shown in FIG. 14B, a part of the step portion 109 is easily folded back and inverted. As a result, the initial reaction force becomes lower than that in the case where an impact is applied to the flat plate portion as shown in FIG.

Further, such a reversal behavior of the stepped portion 109 can occur similarly even when the inner panel 105 is provided on the back surface of the outer panel 103. For example, when the inner panel 105 is provided in the vicinity of the step portion 109 of the concave side flat surface portion 113 as shown in FIG. 15, the step portion 109 is inverted regardless of the inner panel 105, and as shown in FIG. The inner panel 105 so as to straddle the step 109.
16B, the flange portions 105a and 105b of the inner panel 105 are moved in the left-right direction in the figure to expand the inner panel 105, and the step portion 1 is provided as shown in FIG.
09 causes reversal.

The decrease in the initial reaction force may increase the secondary reaction force and the movement distance of the hood.

Here, a waveform (C) of an ideal reaction force characteristic for efficiently absorbing the impact energy by suppressing the moving distance of the hood is shown by a solid line in FIG. The reaction force characteristic is that in the first half of the impact, the initial reaction force rises in a state where the movement distance of the hood is small, and the peak reaction force Fa of a predetermined magnitude is generated.
After reaching the (moving distance Sa), the reaction force decreases as the hood moves, and when the moving distance reaches a predetermined value in the latter half of the impact (moving distance Sb), the secondary reaction of a predetermined magnitude is performed. The force is generated and the decrease in reaction force is alleviated.

Therefore, if the initial reaction force is reduced, it is impossible to absorb the ideal impact energy.
In the conventional hood 101, it is necessary to secure a large moving distance of the hood 101, which makes it difficult to effectively use the space in the engine room.

On the other hand, another conventional automobile hood capable of increasing the initial reaction force is shown in FIGS. 17 and 18 (see Japanese Patent Laid-Open No. 62-214062). FIG. 17 is a perspective view showing an automobile having such a conventional hood.
8 is a sectional view taken along the line KK in FIG.

As shown in FIG. 17, the hood 121 is provided with a hood inner member 123 and a tension rigidity holding member 125 which are polymer-bonded to the back surface of the outer panel 105. The hood inner member 123 has a structure in which a honeycomb core 127 filled with foam is wrapped and the surface is hardened with a hard resin. The hood inner member 123 includes a peripheral edge reinforcing portion 123a along the entire peripheral edge of the hood and a lock device attaching portion 12.
The V-shaped reinforcing portion 123b connecting the hinge mounting portion 129 to the hinge member 129 is integrally formed. The tension rigidity holding member 125 surrounded by the hood inner member 123 is the outer panel 105.
It is glued to the back side of and is filled with foam. When the V-shaped reinforcing portion 123b is provided, the initial reaction force can be increased as compared with the case where only the outer panel 105 is provided.

However, since the V-shaped reinforcing portion 123b has a structure in which the honeycomb core 127 filled with the foam is surrounded by the plastic surface material and has a characteristic that it is hard to be crushed and easily cracked, the initial reaction force in the first half of the impact is reduced. The peak value F1 tends to be higher than the desired target value Fa, and the debris such as the honeycomb core 127 is left behind by the hood inner member 12.
Since it remains within 3, the effective crush stroke amount by which the hood 121 can move is narrowed, and the secondary reaction force in the latter half of the impact tends to rise again.

Therefore, the V-shaped reinforcing portion 123b is connected to the step portion 1
When it is provided along the back side of 09, the reaction force characteristic exhibits a waveform (C1) like the one-dot chain line in FIG. 19, and it is difficult to obtain the ideal waveform (C).

Further, since the hood 121 has a structure in which the outer panel 103 is supported by the bending rigidity of the V-shaped reinforcing portion 123b in the longitudinal direction, the hood 121 is easily bent at the central portion of the V-shaped reinforcing portion 123b and becomes hard at the corners. Therefore, the V-shaped reinforcing portion 12
The amount of bending greatly differs between the central portion and the corner portion of 3b, and there is a possibility that the reaction force characteristics may differ each time the impact portion changes along the longitudinal direction of the V-shaped reinforcing portion 123b. Further, since the side wall of the intersection of the V-shaped reinforcing portion 123b and the tension rigidity holding member 125 has high rigidity, and plastic deformation cannot be expected at the time of impact, it is difficult to secure a sufficient movement amount of the hood at the intersection. It was Therefore, the V-shaped reinforcing portion 1
When 23b is provided along the back side of the step portion 109,
It was difficult to obtain almost the same reaction force characteristics in the entire area of the step portion 109.

Further, when an impact is applied to the step portion 109 from the outside and the V-shaped reinforcing portion 123b is pulled to the left and right, the plastic face material forming the outer wall of the V-shaped reinforcing portion 123b is easily broken, so that V In order to ensure the rigidity of the V-shaped reinforcing portion 123b, it is necessary to form the plastic face material to be thick, and the V-shaped reinforcing portion 123b cannot be denied an increase in size and weight.

That is, even with the structure shown in FIG.
It is difficult to efficiently absorb the impact energy by suppressing the movement distance of the hood in the step portion 109.

Therefore, an object of the present invention is to provide an automobile hood capable of efficiently absorbing impact energy by suppressing the movement distance of the hood even if the hood has a step portion.

[0019]

According to the first aspect of the present invention,
In a hood of an automobile in which an inner panel is provided on the back surface of an outer panel having a convex flat surface portion and a concave flat surface portion partitioned by a step portion, the back surface near the step portion of the convex flat surface portion is supported by the inner panel. From the outer panel and the inner panel, a shock absorber is provided between the outer panel and the inner panel, which is supported by the outer panel and the inner panel, and is crushed and deformed when the moving distance of the hood reaches a predetermined value.

The invention according to claim 2 is the hood of an automobile according to claim 1, wherein the inner panel is formed to bulge along a back side of the step portion, and the outer panel is formed so as to straddle the step portion. A closed cross section is formed between the shock absorbers and the shock absorber is disposed in the closed cross section along the back side of the step section, and a truss-like closed cross section is formed in the closed cross section. It is a thing.

The invention according to claim 3 is the hood of an automobile according to claim 2, wherein the shock absorber is joined to the inner panel and supports the vicinity of the step portion of the convex flat surface portion from the back surface. It is characterized in that it is provided with a linear leg portion, and the leg portion forms the truss-shaped closed cross section between the outer panel and the inner panel.

The invention according to claim 4 is the hood for an automobile according to claim 1, wherein the inner panel is adhered to the convex side flange portion and the concave side flat surface portion which are adhered to the convex side flat surface portion. Equipped with a concave side flange portion, the shock absorber,
A substantially flat plate-shaped substrate portion, one side of which is joined to the convex side flange portion and the other side of which is joined to the concave side flange portion, and a portion near the stepped portion of the convex side flat surface portion that projects from the substrate portion and is supported from the back surface. And a supporting portion for performing the operation.

According to a fifth aspect of the present invention, in the automobile hood according to the first aspect, the shock absorber is formed in a tubular shape having a substantially rectangular cross section, and the convex side is formed along the step portion. It is characterized in that it is arranged on the back side of the flat surface portion, and the side wall of the shock absorber is provided with an easily deformable portion which allows the side wall to be deformed.

[0024]

According to the first aspect of the invention, when an impact force is applied to the vicinity of the step portion of the convex flat surface portion, in the first half of the impact, the impact force is transmitted to the inner panel via the impact absorber, and the inner panel moves downward. However, since the movement of the inner panel is restricted by the outer panel, the shock absorber supports the vicinity of the step portion of the convex flat surface portion. Therefore, the stepped portion does not cause the inversion behavior, and a sufficient initial reaction force can be obtained from the state where the movement distance of the hood is small. Also, when the movement distance of the hood increases, the reaction force decreases due to the inertial force of the outer panel, but when the movement distance of the hood reaches a predetermined distance, the shock absorber collapses and deforms, resulting in a secondary reaction force of a desired size. Occurs, and the decrease in reaction force is appropriately alleviated. As a result, ideal reaction force characteristics can be obtained, and the movement distance of the hood can be suppressed to a small value to ensure sufficient energy absorption.

According to the second aspect of the invention, in addition to the function of the first aspect, the inner panel is formed so as to bulge along the back side of the step portion, and the shock absorber is arranged in the closed cross section along the back side of the step portion. Since it is provided, the cross-sectional shape can be made substantially the same over the entire area of the step portion, and similar reaction force characteristics can be obtained.

Further, the inner panel forms a closed cross section between the outer panel and the step section, and the shock absorber forms a truss-like closed cross section in the closed cross section. A strong tension is generated. As a result, the shock absorber can be firmly supported on the inner panel, and desired reaction force characteristics can be stably obtained.

In the third aspect of the invention, in addition to the function of the second aspect, since the leg portions of the shock absorber are substantially linear, a higher initial reaction force can be obtained by the leg portions in the first half of the impact. In the latter half of the impact, an almost constant secondary reaction force can be obtained due to the buckling deformation of the legs, and a more ideal reaction force characteristic can be surely obtained.

According to the invention of claim 4, in addition to the operation of claim 1, one side of the base plate portion of the shock absorber is joined to the convex side flange portion of the inner panel and the other side is joined to the concave side flange portion. In the first half of the impact, the convex deformation of the inner panel and the concave flange of the inner panel do not move in opposite directions, the opening deformation of the inner panel is prevented, and a higher initial reaction force can be obtained in the first impact.

According to the invention of claim 5, in addition to the function of claim 1, since the shock absorber is formed into a tubular body having a substantially rectangular surface, the side wall of the substantially straight shock absorber supports the outer panel, and the shock is applied. In the first half, a high initial reaction force can be obtained by the side wall of the shock absorber, and in the second half of the impact, a nearly constant secondary reaction force can be obtained by the buckling deformation of the side wall, ensuring ideal reaction force characteristics. Can be obtained.

Further, since the easily deformable portion is provided on the side wall, the magnitude of the reaction force can be set arbitrarily, and the ideal reaction force characteristic can be obtained more reliably.

Further, since the shock absorber is arranged along the step portion, substantially the same reaction force characteristics can be obtained in the entire area of the step portion.

Further, since it is not necessary to provide the inner panel along the back side of the step portion, the inner panel can be formed into an optimum shape according to the hood.

[0033]

1 (a) is a plan view of a hood of an automobile according to a first embodiment as viewed from the back side, FIG. 1 (b) is a sectional view taken along line AA of the hood of FIG. 1 (a), and FIG. FIG. 3 is a sectional view of part B of FIG.
FIG. 2 is a sectional view of a B part showing a deformed state of the hood of FIG.

As shown in FIG. 1, the outer panel 3 of the hood 1 is provided with a step portion 5 which is bent and formed. Step 5
Is extended in the vehicle body front-rear direction on both sides of the vehicle width, and is continuous with an inclined surface between a convex flat surface portion 7 at the center of the vehicle width and a concave flat surface portion 9 at both vehicle width end sides. The step portion 5 is provided in a substantially eight shape so as to expand toward the rear side of the vehicle body, and forms a so-called character line in appearance.

The inner panel 1 which forms the skeleton of the hood 1 on the back surface of the outer panel 3 to secure the rigidity of the hood 1.
1 is provided. The inner panel 11 includes a frame portion 13 arranged on the peripheral portion of the outer panel 3, an inner portion 15 arranged between the frame portions 13 along the back side of the step portion 5, the frame portion 13 and the inner portion 15. Has a reinforcement portion 17 connected to
These are integrally provided. As shown in FIG. 1B, the frame portion 13, the inner portion 15, and the reinforcing portion 17 are each formed into a substantially inverted hat shape in cross section.

As shown in FIG. 2, the inner portion 15 is
The outer panel 3 and the inner portion 15 are arranged so as to straddle the back side of the step portion 5 of the outer panel 3, and the outer panel 3 and the inner portion 15 are in a state of mutually bulging. The inner portion 15 includes a bottom portion 23 and side wall portions 25 and 27 that are bent obliquely upward from both ends of the bottom portion 23.
The convex side flange portion 25a and the concave side flange portion 27a are formed at the end portions of the both side wall portions 25 and 27 by bending outward. The convex side flange portion 25a is adhered to the back surface of the convex side flat surface portion 7 of the outer panel 3 by a mastic 29, and the concave side flange portion 27a is adhered to the rear surface of the concave side flat surface portion 9 by a mastic 29. As a result, a closed cross section N is formed between the inner portion 15 and the outer panel 3.

In this closed section N, a shock absorber 21 is arranged along the back side of the step portion 5. Shock absorber 2
Reference numeral 1 denotes an upper plate portion 31 having a substantially hat-shaped cross section, and linear leg portions 33 bent downward from both ends of the upper plate portion 31,
And 35. The lower ends of the both leg portions 33 and 35 hit the bending corner portions (J, K) between the bottom portion 23 and the side wall portions 25 and 27, bend along the inner surfaces of the side wall portions 25 and 27, and Joints 33a and 35a are formed. The joint portions 33a and 35a are spot-welded to the side wall portions 25 and 27 (joint positions T1 and T2), respectively, whereby the shock absorber 21 is fixed to the inner panel 15.

The upper surface portion 31 of the shock absorber 21 is arranged so as to be close to or in contact with the vicinity of the step portion 5 of the convex side flat surface portion 7, and supports the vicinity of the step portion 5 of the convex side flat surface portion 7 from the back surface. There is. The shock absorber 21 divides the closed cross section N into three spaces, and between the leg sections 33 and 35 and the outer panel 3, substantially truss-like closed cross sections 37 and 39 are formed.

Next, the operation will be described.

As shown in FIG. 2, when the impact force P acts on the stepped portion 5 of the outer panel 3, the impact absorbing body 21 is pressed downward and tries to push down the inner portion 15 at the lower ends of the leg portions 33 and 35. , Both flange portions 25a of the inner portion 15,
27a is bonded to the back surface of the outer panel 3 by a mastic 29, the inner portion 15 forms a closed cross section N between the outer panel 3 and the step section 5, and the shock absorber 21 has a closed cross section N. Since the truss-shaped closed sections 37 and 39 are formed in the inner part 15, a strong tension is generated in the inner portion 15 at the time of impact, and the impact absorber 21 is firmly supported by the inner panel 11. Further, the lower ends of the leg portions 33 and 35 abut on the bent corner portions (J, K) between the bottom portion 23 and the side wall portions 25 and 27, and are spot welded to the side wall portions 25 and 27 at the joint portions 33a and 35a. Therefore (the joining positions T1 and T2), the leg portions 33 and 35 do not open and move in opposite directions due to the impact. Therefore, the vicinity of the step portion 5 of the convex side flat surface portion 7 is supported by the shock absorber 21, the reaction force of the hood 1 is rapidly increased without causing the outer panel 3 to be reversed at the step portion 5, and a desired initial reaction force can be obtained. Obtainable.

When the load due to the impact force P reaches a predetermined value, the leg portions 33 and 35 of the impact absorber 21 start to buckle and deform, and the reaction force decreases. In the latter half of the impact after the reduction of the reaction force, as shown in FIG. 3, the impact absorber 21 and the inner panel 15 shift to large deformation and a secondary reaction force can be obtained.

At this time, the leg portions 33, 3 of the shock absorber 21
Since 5 is substantially linear, in the first half of the impact, the legs 33, 3
5, a higher initial reaction force can be obtained, and in the latter half of the impact, a substantially constant secondary reaction force can be obtained by buckling deformation of the legs 33, 35.

As a result, the ideal reaction force characteristic waveform (C) shown in FIG. 19 can be obtained, and the movement distance of the hood 1 can be suppressed to a small value to ensure sufficient energy absorption. Therefore, even with the hood 1 having the step portion 5,
The impact can be effectively mitigated by suppressing the reversal behavior of the step portion 5.

Further, since the inner portion 15 of the inner panel 11 is formed to bulge along the back side of the step portion 5 and the shock absorber 21 is arranged in the closed cross section portion N along the back side of the step portion 5, the step The cross-sectional shape of the hood 1 can be made substantially the same in the entire area of the portion 5. As a result, the same reaction force characteristics can be obtained in the entire area of the step portion 5, and the impact can be effectively mitigated.

FIG. 4 shows a modification of this embodiment.

The inner portion 15 of the hood 40 according to this modification has left and right slanted portions 43 and 45, and both slanted portions 4 are provided.
3, 45 are bent so that a cross section perpendicular to the longitudinal direction of the inner portion 15 has a substantially V-shape (reverse mountain shape) bulging to the back side. One of the slanted portions 43 extends toward the back surface of the convex flat surface portion 7, and the other slant portion 45 extends toward the back surface of the concave flat surface portion 9. At the ends of the both oblique parts 43 and 45,
The convex side flange portion 43a and the concave side flange portion 45a are formed to be bent outward, and both flange portions 43a and 45a are formed.
Is a mastic 2 on the back surface of the convex side plane portion 7 and the concave side plane portion 9.
Bonded by 9.

The shock absorbing member 41 includes the upper plate portion 47 and the leg portion 4.
9 and the inclined portion 51, which are integrally bent. The leg portion 49 has a lower end on the left and right slanted portions 43, 45
It hits the inner corner of the bending point M between and the upper end is the convex side flat surface portion 7.
And extends substantially perpendicularly to the back surface of the convex flat surface portion 7. The upper plate portion 47 is bent from the upper end of the leg portion 49 to the opposite side of the step portion 5, and is further folded back to the step portion 5 side. The inclined portion 51 extends from the upper plate portion 47 through the back side of the step portion 5 to the back surface of the concave side flat surface portion 9. The lower end of the leg portion 49 is provided with a joint portion 49a on one side that is bent along the inside of the one slanting portion 43, and the joint portion 4 on the one side is provided.
9a is spot welded to one of the slanted portions 43 (joint position T3). At the end of the inclined portion 51, a joint portion 51a on the other side that is bent along the concave side flange portion 45a is provided, and the joint portion 51a on the other side is the flange portion 45a.
It is spot welded (joint position T4). The other-side joining portion 51a is provided along the back surface of the concave-side flat surface portion 9,
The mastic 29 adheres to the back surface of the concave flat surface portion 9 together with the flange portion 45a.

In this modification, the same operation and effect as those of the first embodiment can be obtained.

That is, when an impact force is applied to the step portion 5 of the outer panel 3, the impact absorber 41 is pressed downward and tries to push down the inner portion 15, but both flange portions 43a and 45a of the inner portion 15 have outer flanges. 3, the inner portion 15 forms a closed cross-section portion N between the inner panel 15 and the outer panel 3 across the step portion 5, and the shock absorber 41 has a truss shape on the closed cross-section portion N. Since the closed sections 53 and 55 are formed, a strong tension is generated in the inner portion 15 at the time of impact, and the impact absorber 41
Are firmly supported by the inner panel 11. Also leg 49
Since the lower end of the abutment hits the inner corner of the bending point M between the left and right slanted portions 43, 45 and is spot welded to the slanted portion 43 at the joint 49a (joint position T3), the leg portion is affected by the impact force. The lower end of 49 does not move. Therefore, the vicinity of the step portion 5 of the convex side flat surface portion 7 is supported by the shock absorber 21, the reaction force of the hood 1 is rapidly increased without causing the outer panel 3 to be reversed at the step portion 5, and a desired initial reaction force can be obtained. Obtainable.

When the load due to the impact force reaches a predetermined value, the leg portion 49 of the impact absorber 41 starts to buckle and deform, and the reaction force decreases. In the latter half of the impact after the reaction force is reduced, the shock absorber 49 and the inner panel 15 shift to large deformation, and the secondary reaction force can be obtained.

At this time, since the leg portion 49 of the shock absorber 41 is substantially linear, a higher initial reaction force can be obtained by the leg portion 49 in the first half of the impact, and the seat 49 of the leg portion 49 is obtained in the latter half of the impact. An almost constant secondary reaction force can be obtained by bending deformation.

As a result, the ideal reaction force characteristic waveform (C) shown in FIG. 19 can be obtained, and the movement distance of the hood 40 can be suppressed to a sufficient level to ensure sufficient energy absorption. Therefore, even with the hood 40 having the step portion 5, the inversion behavior of the step portion 5 can be suppressed and the impact can be effectively mitigated.

Further, since the inner portion 15 of the inner panel 11 is formed to bulge along the back side of the step portion 5 and the shock absorber 41 is arranged in the closed cross section portion N along the back side of the step portion 5, The cross-sectional shape of the hood 40 can be made substantially the same in the entire area of the portion 5. As a result, the same reaction force characteristics can be obtained in the entire area of the step portion 5, and the impact can be effectively mitigated.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a sectional view of a main part of an automobile hood according to the second embodiment, and FIG. 6 is a perspective view showing the inner portion and the shock absorbing member of FIG. The same reference numerals are given and the description thereof is omitted.

As shown in FIG. 5, the impact absorbing member 61 of the hood 60 according to this embodiment includes a substrate portion 63 and a supporting portion 65, and is provided along the back side of the step portion 5. The board portion 63 is formed in a substantially flat plate shape so as to linearly connect the convex side flange portion 25a and the concave side flange portion 27a of the inner panel 11, and is formed so as to close the opening upper surface of the inner portion 15 and the inner portion 15. The outer panel 3 and the outer panel 3 are sandwiched together. At both ends of the substrate portion 63, the joint portions 63
a and 63b are provided. Both joints 63a, 63b
Is joined to the convex side flange portion 25a and the concave side flange portion 27a of the inner panel 11 (joint positions T5, T6),
The flanges 25a and 27a are bonded to the rear surfaces of the convex flat surface portion 7 and the concave flat surface portion 9 by a mastic 29.

The support portion 65 is formed by cutting and raising a part of the substrate portion 63 into a substantially rectangular shape, and is formed integrally with the substrate portion 63. The support portion 65 includes two leg portions 65b that are erected from the substrate portion 63 substantially vertically to the back surface of the convex-side flat surface portion 7,
An upper surface portion 65a is provided between the both leg portions 65b so as to be close to or in contact with the step portion 5 of the convex flat surface portion 7.

Next, the operation will be described.

When the impact force P acts on the step portion 5 of the outer panel 3, the impact absorber 61 is pressed downward, but the joint portions 63a and 63b of the substrate portion 63 are adhered to the back surface of the outer panel 3 by the mastic 29. Since the joint portions 63a and 63b of the board portion 63 are joined to the convex side flange portion 25a and the concave side flange portion 27a of the inner panel 11 (joint positions T5 and T6), the convex side flange portion of the inner portion 15 is formed. Opening deformation of the inner portion 15 is prevented without the portions 25a and the concave side flange portion 27a moving in opposite directions. Therefore, the vicinity of the step portion 5 of the convex side flat surface portion 7 is supported by the support portion 65 of the shock absorber 61, and the outer panel 3 does not invert at the step portion 5 and the hood 60.
The reaction force of is rapidly increased, and a desired initial reaction force can be obtained.

When the load due to the impact force reaches a predetermined amount, the leg portion 65b of the impact absorber 61 starts to buckle and deform, and the reaction force decreases. In the latter half of the impact after the reaction force is reduced, the shock absorber 61 and the inner panel 15 shift to large deformation, and the secondary reaction force can be obtained.

At this time, since the leg portions 65b of the shock absorber 61 are substantially linear, a higher initial reaction force can be obtained by the leg portions 65b in the first half of the impact, and in the latter half of the impact.
Due to the buckling deformation of the legs 65b, a substantially constant secondary reaction force can be obtained.

As a result, the waveform (C) of the ideal reaction force characteristic shown in FIG. 19 can be obtained, and the movement distance of the hood 60 can be suppressed to be small and sufficient energy absorption can be secured. Therefore, even with the hood 60 having the step portion 5, the inversion behavior of the step portion 5 can be suppressed and the impact can be effectively mitigated.

Further, since the inner portion 15 of the inner panel 11 is formed so as to bulge along the back side of the step portion 5 and the shock absorber 61 is provided along the back side of the step portion 5, the same as in the first embodiment. The cross-sectional shape of the hood 60 can be made substantially the same in the entire area of the step portion 5, and in the entire area of the step portion 5,
Similar reaction force characteristics can be obtained, and impact can be effectively mitigated.

Next, a third embodiment of the present invention will be described.

FIG. 7 (a) is a plan view of the hood of an automobile according to the third embodiment as viewed from the back side, and FIG. 7 (b) is FIG. 7 (a).
8 is a cross-sectional view of the hood of FIG.
FIG. 9 is a side view of the shock absorber. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 7, on the outer panel 3 of the hood 70, a step portion 5 is formed by bending. The skeleton of the hood 1 is formed on the back surface of the outer panel 3 to form the hood 1.
The inner panel 71 that secures the rigidity of is provided.
The inner panel 71 includes a frame portion 73 arranged on a peripheral portion of the outer panel 3 and a V-shaped inner portion 7 arranged in a substantially V shape from both ends of a vehicle width behind the vehicle body toward a vehicle width center in front of the vehicle body.
5, and a reinforcing portion 77 connected to the frame portion 73 and the V-shaped inner portion 75, which are integrally provided.

The shock absorber 81 is arranged along the back side of the step portion 5 of the outer panel 3, and has a top surface portion 83, a bottom surface portion 85, and two side wall portions 87 and 89, as shown in FIG. It is formed in a tubular shape having a substantially rectangular cross section. Bottom part 85
Is spot-welded to the bottom surface 79a of the recess 79 formed by notching the side wall portion 71a of the inner panel 71 (joint position T
7), the upper surface portion 83 is adhered to the rear surface in the vicinity of the step portion 5 of the convex flat surface portion 7 by the mastic 91. That is,
The shock absorber 81 includes an outer panel 3 and an inner panel 71.
It is sandwiched between the two.

As shown in FIG. 9, on both side wall portions 87 and 89 of the shock absorber 81, grooves 93 as easily deformable portions are provided on the outer panel 3 side in a direction substantially perpendicular to the longitudinal direction of the shock absorber 81. A notch is formed toward the inner panel 71 side. The inner panel 71 is bonded to the outer panel 3 by the mastic 29 as in the first embodiment.

Next, the operation will be described.

When the impact force P acts on the step portion 5 of the outer panel 3, the impact force P is transmitted to the inner panel 71 through the impact absorber 81, and the side wall portion 71a of the inner panel 71 is bent so as to be bent in the recess 79. However, the inner panel 71 is the outer panel 3 by the mastic 19.
Since it is adhered to the hood 70, it is not easily deformed, the vicinity of the step portion 5 of the convex side flat surface portion 7 is supported by the upper surface portion 83 of the shock absorber 81, and the outer panel 3 does not reverse at the step portion 5 and the hood 70 of the hood 70 is prevented. The reaction force is rapidly increased, and a desired initial reaction force can be obtained.

When the load due to the impact force reaches a predetermined magnitude, the side wall portions 87 and 89 of the impact absorber 81 start to buckle and deform, and the reaction force decreases. In the latter half of the impact after the reaction force decreases, the shock absorber 81 and the inner panel 15 shift to large deformation, and the secondary reaction force can be obtained.

At this time, the side wall portion 87 of the shock absorber 81,
Since 89 is substantially linear, in the first half of the impact, the side wall portion 8
A higher initial reaction force can be obtained with 7,89,
In the latter half of the impact, an almost constant secondary reaction force can be obtained by the buckling deformation of the side wall portions 87, 89.

As a result, the waveform (C) of the ideal reaction force characteristic shown in FIG. 19 can be obtained, and the movement distance of the hood 70 can be suppressed to a small value to ensure sufficient energy absorption. Therefore, even with the hood 70 having the step portion 5, the inversion behavior of the step portion 5 can be suppressed and the impact can be effectively mitigated.

Further, since the shock absorber 81 is provided along the back side of the step portion 5, the cross-sectional shape of the hood 70 is substantially the same in the entire area of the step portion 5 as in the first and second embodiments. And in the entire area of the step portion 5,
Similar reaction force characteristics can be obtained, and impact can be effectively mitigated.

Furthermore, since it is not necessary to provide the inner panel 71 along the back side of the step portion 5, the inner panel 71 can have an optimum shape that fits the hood 70.

[0076]

As described above, according to the first aspect of the invention, after the impact on the vicinity of the step portion of the convex side plane portion,
Since the shock absorber supports the vicinity of the step on the convex flat surface,
A sufficient initial reaction force can be obtained from the state where the hood has a small moving distance without causing the stepped portion to invert. Also,
When the moving distance of the hood increases to reach a predetermined distance, the impact absorbing body is crushed and deformed to generate a secondary reaction force of a desired magnitude, and the reduction of the reaction force is appropriately mitigated. As a result, ideal reaction force characteristics can be obtained, the movement distance of the hood can be suppressed to a small extent, sufficient energy absorption can be ensured, and impact can be effectively mitigated.

According to the invention described in claim 2, in addition to the effect of claim 1, the impact can be effectively mitigated in the entire area of the step portion.

Further, by the closed cross section and the truss-like closed cross section, desired reaction force characteristics can be stably obtained, and the impact can be more effectively and surely mitigated.

According to the third aspect of the invention, in addition to the effect of the second aspect, the substantially linear leg portion can surely obtain a more ideal reaction force characteristic, and the impact is further effective. It can certainly be alleviated.

According to the invention of claim 4, in addition to the action of claim 1, in the first half of the impact, the opening deformation of the inner panel is prevented by the base plate portion of the impact absorber, so that the initial reaction force in the first half of the impact is reduced. It can be further increased.

According to the invention of claim 5, in addition to the action of claim 1, a high linear reaction force can be obtained in the first half of the impact and substantially constant in the latter half of the impact due to the side wall of the substantially linear impact absorber. The secondary reaction force can be obtained, and the ideal reaction force characteristic can be surely obtained, so that the impact can be more effectively and surely mitigated.

Further, the size of the reaction force can be arbitrarily set by the easily deformable portion, and the ideal reaction force characteristic can be more surely obtained.

Further, the impact can be effectively mitigated over the entire area of the step portion.

Furthermore, since it is not necessary to provide the inner panel along the back side of the step portion, the inner panel can be formed into an optimum shape according to the hood.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment, (a) is a plan view,
(B) is an AA sectional view of (a).

FIG. 2 is an enlarged view of a B part in FIG.

FIG. 3 is a cross-sectional view showing a modified state of FIG.

FIG. 4 is a sectional view showing a modification of the first embodiment.

FIG. 5 is a sectional view showing a second embodiment.

FIG. 6 is a perspective view showing a second embodiment.

7A and 7B are views showing a third embodiment, in which FIG. 7A is a plan view and FIG. 7B is a sectional view taken along line U-U of FIG.

FIG. 8 is a cross-sectional view taken along line VV of FIG.

FIG. 9 is a cross-sectional view of an essential part of the third embodiment.

FIG. 10 is a plan view of a conventional example.

11 is an enlarged view of a main part of FIG.

12A and 12B are schematic diagrams showing a deformed state of the outer panel, in which FIG. 12A shows a state before deformation and FIG. 12B shows a state at the time of deformation.

FIG. 13 is an external perspective view of a hood having a step portion.

FIG. 14 is a schematic view showing a deformed state of a step portion,
(A) shows the state before deformation, (b) has shown the state at the time of deformation.

FIG. 15 is a cross-sectional view showing a deformed state when an inner panel is provided on the step portion.

FIG. 16 is a cross-sectional view showing another deformed state in the case where an inner panel is provided at the step portion, (a) shows the state before the deformation, and (b) shows the state after the deformation.

FIG. 17 is a perspective view of another conventional example.

18 is a cross-sectional view showing a modified state of FIG.

FIG. 19 is a diagram showing reaction force characteristics.

[Explanation of symbols]

 1 Hood 3 Outer panel 5 Stepped portion 7 Convex side flat surface portion 9 Concave side flat surface portion 11 Inner panel 21 Shock absorber 25a Convex side flange portion 27a Concave side flange portion 33 Leg portion 35 Leg portion 37 Truss closed cross section 39 Truss closed cross section 40 Hood 41 Shock Absorber 49 Legs 53 Truss Closed Cross Section 55 Truss Closed Cross Section 60 Hood 61 Shock Absorber 63 Substrate 65 Support Part 70 Hood 71 Inner Panel 81 Shock Absorber 87 Side Wall 89 Side Wall 93 Groove (Easy Deformation Part) ) N closed section

Claims (5)

[Claims] 1. A hood of an automobile having an inner panel provided on a back surface of an outer panel having a convex flat surface portion and a concave flat surface portion divided by a step portion, the hood being supported by the inner panel and having the convex flat surface portion. Between the outer panel and the inner panel, a shock absorber is provided between the outer panel and the inner panel, which supports the vicinity of the step portion from the back surface and causes a crushing deformation to generate a desired reaction force when the movement distance of the hood reaches a predetermined size. Car hood to do. 2. The hood for an automobile according to claim 1, wherein the inner panel is formed to bulge along a back side of the step portion, and a closed cross-section portion is formed between the outer panel and the step portion. The shock absorber is disposed in the closed cross section along the back side of the step, and a truss-like closed cross section is formed in the closed cross section. 3. The automobile hood according to claim 2, wherein the shock absorber includes a substantially linear leg portion that is joined to the inner panel and supports the vicinity of the step portion of the convex flat portion from the back surface. The automobile hood, wherein the leg portion forms the truss-shaped closed cross section between the outer panel and the inner panel. 4. The automobile hood according to claim 1, wherein the inner panel includes a convex side flange portion bonded to the convex side flat surface portion and a concave side flange portion bonded to the concave side flat surface portion. The shock absorber includes a substantially flat plate-shaped substrate portion, one side of which is joined to the convex side flange portion and the other side of which is joined to the concave side flange portion, and the convex side flat surface portion projecting from the substrate portion. A hood for an automobile, characterized in that a support portion for supporting the vicinity of the step portion of the above from the back is provided. 5. The automobile hood according to claim 1, wherein the shock absorber is formed in a tubular shape having a substantially rectangular cross section, and is arranged on the back side of the convex flat portion along the step portion. A hood for an automobile, wherein a side wall of the shock absorber is provided with an easily deformable portion that allows deformation of the side wall.