JPH05139338A - Hood impact absorbing device - Google Patents

Abstract

PURPOSE:To improve the protecting performance for a pedestrian by forming a flat characteristic of the hood reaction force characteristic in the interference with the head part of the pedestrian. CONSTITUTION:An energy absorbing body 1 which possesses the characteristic for the pressure destruction shift having a peak is installed at the part where a rib 3 does not exist between the ribs 3 and 3 on the reverse surface 2a of a hood outer plate 2 and the part where the clearance from the built-in article 4 in an engine room is little. The energy absorbing body 1 has a shallow dome 5 shape which is formed by bulging up a thin plate so that the center part forms a hill, and a number of first row holes 7 are formed along the outer periphery 6 of the dome 5. The outer periphery of the first row hole 7 is turned back in the reverse direction to the dome 5, and a deformation part 8 is formed, and a number of second row holes 9 are formed in the deformation part 8. Further, the turned-back outer peripheral edge part 10 is joined with the rib 3 through the sport welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hood impact absorbing device for protecting pedestrians.

[0002]

2. Description of the Related Art As a conventional hood impact absorbing device, for example, there is one as shown in FIG. 13 (for example, as similar inventions, Japanese Utility Model Publication No. 61-67265 and Japanese Utility Model Publication No. 61-26).
682 and the like).

That is, in this conventional device, a shock absorber 102 having a U-shaped cross section is joined with an adhesive 103 at the AA cross section position on the back surface of the hood 101 shown in FIG.

When a pedestrian interferes with the upper surface of the hood 101, the surface of the hood 101 is pressed downward, and the energy absorber 102 is pressed against the built-in object 104 in the engine room. The energy absorber 102 that has been pressure-welded has a built-in object 104.
The protrusion 105 provided on the pressure contact portion is crushed without sliding to absorb impact energy.

[0005]

However, in such a conventional hood impact absorbing device, the cross section is U-shaped, and both ends thereof are bonded to the back side of the hood with an adhesive. , When the energy absorber is compressed,
It has a structure in which the internal space having a U-shaped cross section is narrowed.

Therefore, as shown in FIG. 15, the reaction force of the energy absorber tends to increase as the amount of compressive displacement increases, and increases particularly in the latter half. In the reaction force mode of the hood outer plate, the reaction force tends to rise sharply in the initial stage of compression, fall in the middle, and rise again in the latter half. For this reason, the total reaction force drops in the middle and becomes a high reaction force in the latter half, so there is a problem that a large space is required to increase the energy absorption amount.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a hood impact absorbing device having a small size and a flat energy absorbing characteristic.

[0008]

Therefore, according to the present invention, an energy absorber having a peak of reaction force against crush displacement in collision crush is arranged on the back side of the hood,
The low reaction force region of the hood outer plate is not supplemented by the energy absorber, and the total reaction force characteristic is flat.

[0009]

When the head of the pedestrian interferes with the upper surface of the hood, the outer plate of the hood is deformed and the energy absorber is compressed during the compression deformation.

On the other hand, in the reaction force mode of the hood outer plate, the reaction force tends to rise rapidly in the initial stage of compression, fall in the middle, and rise again in the latter period. The intermediate low reaction force region is supplemented by the energy absorber having a single peak, resulting in a flat energy absorption characteristic as a whole.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of the present invention, FIG. 1 is a perspective view showing a cross section of a central part of a hood cut left and right, and FIG.
Sectional drawing of a cutting surface, FIG. 3 is an enlarged view of FIG. 1A part.

First, the configuration will be described. Energy absorber 1
Is attached to a portion where there is no rib 3 between the ribs 3 on the back surface 2a of the hood outer plate 2 and where there is little clearance with the engine room internal component 4.

The energy absorber 1 has a shape of a shallow dome 5 in which a thin plate is raised so that a central portion thereof becomes a hill,
A large number of first rows of holes 7 are provided along the outer periphery 6 of the dome 5. The outer periphery of the holes 7 in the first row is folded back in the opposite direction to the dome 5 to form a deformed portion 8, and the deformed portion 8 is provided with a large number of holes 9 in the second row. Further, the folded back outer peripheral end 10 is joined to the rib 3 by spot welding 11.

Next, the operation will be described with reference to FIGS. As shown in FIG. 4, when a pedestrian collides with a vehicle and the head 12 interferes with the upper surface of the hood outer plate 2, the hood outer plate 2 rising in the central portion is pressed and becomes flat. To do. At this time, the hood outer plate 2 bulges around the point of interference with the pedestrian head 12 in an attempt to expand outward.

As shown in FIG. 7, the hood outer plate 2 generates a large reaction force at the initial stage of compression.

Further, when the compression of the hood outer plate 2 progresses and the hood outer plate 2 starts to be depressed downward as shown in FIG. 5,
The stress around the point of interference with the pedestrian head 12 is relaxed, and the reaction force of the hood outer plate 2 tends to drop as shown in FIG. 7. On the other hand, the hood outer plate 2 interferes with the top of the dome 5 of the energy absorber 1, the dome 5 is pushed downward, the outer periphery of the dome 5 spreads outward, and is plastically deformed into a flat shape. A large amount of reaction force is generated.

This reaction force of the energy absorber 1 compensates for the decrease in reaction force of the hood outer plate 2 which tends to fall.

When the hood outer plate 2 further moves downward, the hood outer plate 2 is strongly pulled in the direction of the interference point with the pedestrian head 12, as shown in FIG. 6, and as shown in FIG. The hood skin 2 again generates a high reaction force. On the other hand, the energy absorber 1 deforms flat and shifts to a reactionless state.

As described above, when the reaction force of the hood outer plate 2 is reduced, the reaction force of the energy absorber 1 acts on the hood outer plate 2, so that the total reaction force exerted on the pedestrian head 12 is shown in FIG. As shown in 7, it remains almost constant. Therefore, injuries to pedestrians when an accident occurs are reduced.

FIG. 8 shows a second embodiment of the present invention. In this embodiment, a rib 13 for reinforcing the hood outer plate 2 and an energy absorber 14 having the same basic structure as that of the first embodiment are integrally formed and attached to the back surface of the hood outer plate 2.

According to this embodiment, the same effects as those of the first embodiment can be obtained, and since the number of parts is small, it is excellent in terms of cost and manufacturing process.

9 to 10 show a third embodiment of the present invention. In this embodiment, as shown in FIG. 10, a single thin plate 16 is provided with a number of U-shaped notches 17, and the inner portion surrounded by the U-shaped notches 17 is folded to one side of the thin plate 16. The energy absorber 15 is formed by raising the long leg 18 and the short leg 19 which are erected at right angles or diagonally (FIG. 9 and FIG. 10 show the case of diagonal). Then, the energy absorber 15 is provided between the hood outer plate 2 and the clearance 2
With 0 secured, the periphery of the thin plate 16 is joined to the flange 21 integrally formed with the rib 3 by spot welding 22 and attached to the hood outer plate 2.

The material of the thin plate 16 is an iron plate (S40C, etc.)
Alternatively, a plastic resin or the like that breaks when it reaches a certain curvature is used. The breakage strength is controlled by the notch 23 provided at the base of the long leg 18 and the short leg 19.

When the head of the pedestrian interferes with the hood outer plate 2 and the hood outer plate 2 is deformed, a load acts on the energy absorber 15. Then, the long legs 18 and the short legs 19 hit the engine room internal component 4 and exert a reaction force while bending. Then, the hood outer plate 2 is further deformed and the long leg 18 and the short leg 19 are
When the load acting on the load exceeds a certain load, the load breaks and loses the reaction force, and the same reaction force characteristics as those of the first embodiment are exhibited.

11 to 12 show a fourth embodiment of the present invention. In this embodiment, a dish-shaped energy absorber 25 is joined to one side of a thin plate 24 joined to the flange of the rib 3 by spot welding 27 or an adhesive.

The dish-shaped energy absorber 25 has a hole 26 in the center thereof so that the dish-shaped energy absorber 25 is relatively easily deformed even when the height (h) is large. Further, the spot welded portion 27 is provided so as to project from the dish-shaped energy absorber 25 through the fuse structure portion 28, and the head of the pedestrian interferes with the hood outer plate 2 so that the dish-shaped energy absorber 25.
The fuse structure 28 can be easily cut when a load is applied to the outer periphery of the dish-shaped energy absorber 25 and the outer periphery of the dish-shaped energy absorber 25 expands outward.

According to this embodiment, the same effect as the above embodiment can be obtained, and since the fuse structure 28 is provided, it is possible to surely obtain the peak characteristic of one peak.

[0028]

As described above, according to the present invention, the reaction force of the hood on the pedestrian can be made substantially flat. Therefore, it is possible to reduce injuries to pedestrians when an accident occurs.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention in which a central portion of a hood is cut left and right.

FIG. 2 is a cross-sectional view showing a cross section of FIG.

FIG. 3 is an enlarged perspective view showing a portion A of FIG.

FIG. 4 is a cross-sectional view illustrating the initial state of the hood compression of the first embodiment.

FIG. 5 is a cross-sectional view illustrating the state of the hood compression middle stage of the first embodiment.

FIG. 6 is a sectional view for explaining a state of the hood compression latter stage of the first embodiment.

FIG. 7 is a view showing the relationship between the hood compression stroke and the reaction force of the first embodiment.

FIG. 8 is a sectional view showing a second embodiment of the present invention.

FIG. 9 is a sectional view showing a third embodiment of the present invention.

FIG. 10 is a perspective view showing a third embodiment of the same.

FIG. 11 is a sectional view showing a fourth embodiment of the present invention.

FIG. 12 is a perspective view showing a fourth embodiment of the same.

FIG. 13 is a perspective view showing a conventional example.

FIG. 14 is a perspective view illustrating a mounting position of an energy absorber.

FIG. 15 is a diagram showing a relationship between a conventional hood compression stroke and a reaction force.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Energy absorber 2 ... Hood outer plate 3 ... Rib 4 ... Engine room internals 5 ... Dome 7 ... First row hole 8 ... Deformation part 9 ... Second row hole 12 ... Pedestrian head 14 ... Energy absorption Body 15 ... Energy absorber 16 ... Thin plate 18 ... Long leg 19 ... Short leg 24 ... Thin plate 25 ... Dish-shaped energy absorber 26 ... Hole 28 ... Fuse structure part

Claims (1)

[Claims] 1. An energy absorber having a peak of reaction force against crushing displacement in collision crushing is arranged on the back side of a hood, and a low reaction force region of a hood outer plate is supplemented by the energy absorbing body. A hood impact absorbing device characterized by a flat total reaction force characteristic.