JPH0834302A - Shock absorbing bumper - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a shock absorbing bumper that is lighter and less expensive than conventional products and has higher rigidity than conventional products. A shock absorbing bumper including a metal reinforcement provided with a vehicle body mounting member, a skin material, and an energy absorbing material made of a synthetic polymer foam between the two, A shock absorbing bumper characterized in that the reinforcement is a hollow shape manufactured by bending. The impact absorbing bumper described above, wherein a reinforcing member made of a hollow metal that crosses the longitudinal direction of the reinforcement is provided inside the reinforcement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing bumper used in an automobile, and more particularly to a shock absorbing bumper which is lightweight and has high rigidity.

[0002]

2. Description of the Related Art A shock absorbing bumper for a vehicle has a role of absorbing a shock when the vehicle comes into contact with an external object, preventing damage to the vehicle body, and the like. Molecularization is progressing. However, since the shock absorbing bumper needs to be rigid, most of the reinforcement constituting the backup beam of the bumper is made of metal, and there is an attempt to make it of an aluminum alloy for weight reduction. No progress has been made because the price is nearly three times that of conventional products. It has also been attempted to make the reinforcement made of glass fiber reinforced polypropylene,
Since this product is more expensive than aluminum alloy, it is used only in special cases. Therefore, most of today's automobiles use the shock absorbing bumper shown in FIGS.

FIG. 3 is an exploded perspective view showing the outline of a general shock absorbing bumper, 1 is an energy absorbing material formed of a synthetic polymer foam, 2 is a synthetic polymer skin, and 3 is a synthetic polymer skin.
High tension steel reinforcement, 9
Is a vehicle body mounting member. FIG. 4 is a cross-sectional view of the longitudinal center portion of the shock absorbing bumper shown in FIG. As can be seen from this figure, the reinforcement 3 is formed by spot welding the above-mentioned material press-formed into a U-shape at the welding margin 4 provided at the end. There is a problem that the side surface 5 becomes thin due to molding. In addition, there is a problem that it becomes heavy because two welding margins must be provided. As a result, the conventional shock absorbing bumper is not so high in rigidity as compared with the weight.
On the other hand, safety regulations have been tightened year by year to prevent automobile accidents, and recently, increasing the rigidity of the central part of the shock absorbing bumper has become an issue. Therefore, in Japan, it is inevitable that the rigidity of the portion will be legally regulated in the near future, which will lead to an increase in the weight of the shock absorbing bumper and a change of material, which causes an increase in the vehicle price and an increase in the fuel consumption.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems found in conventional shock absorbing bumpers, and provides a shock absorbing bumper that is lighter and less expensive than conventional products and has higher rigidity than conventional products. The task is to provide.

[0005]

The present inventors have completed the present invention as a result of intensive research to solve the above problems. That is, according to the present invention, an impact composed of a metal reinforcement provided with a vehicle body mounting member, a skin material, and an energy absorbing material made of a synthetic polymer foam between the both. In the absorption bumper, there is provided an impact absorption bumper characterized in that the reinforcement is a hollow shape manufactured by bending. Further, according to the present invention, there is provided the above-described shock absorbing bumper, characterized in that a reinforcing member is provided inside the reinforcement so as to traverse the longitudinal direction of the reinforcement.

The shock absorbing bumper of the present invention is characterized by using a hollow reinforcement manufactured by bending. Since the reinforcement is manufactured by a bending method such as a roll forming method, a welding margin is unnecessary or only one place is required, and since no press working is performed, a side surface seen in a conventional metal reinforcement. There is no reduction in thickness, which makes it a lightweight and highly rigid reinforcement. The roll forming method is a method of sequentially bending a coil flat plate with a roll to form a specified cross-sectional shape. This is a hollow material forming method. If a hole or the like is required in the target hollow material, it may be formed before bending, and the long hollow material obtained by this method is cut into a desired length and then bent by a bender or the like. If so, a reinforcement along the shape of the vehicle body side surface of the energy absorbing material can be obtained.

In the shock absorbing bumper of the present invention, the material used for the reinforcement may be a metal material having high rigidity, and the high tension steel used for the conventional reinforcement is preferably used. Then, comparing the reinforcements made of the same material so as to have the same rigidity, those manufactured by the roll forming method are 15% or more lighter than the products manufactured by the conventional method. Therefore, the cost of the product obtained by the roll forming method is 10% or more lower than that of the conventional method. According to the detailed study results by the present inventors, when a reinforcement is manufactured by using a high tension steel having a thickness of 1.6 mm by a conventional method, the side wall portion of the reinforcement is stretched due to stretching during press working. Has an average thickness of 0.
The thickness was 8 mm, and the thinnest portion was 0.6 mm, but in the reinforcement produced by the roll forming method, almost no change in plate thickness was observed.

In the shock absorbing bumper of the present invention, a synthetic polymer foam such as polyolefin is usually used as the energy absorbing material, but it is particularly preferable to use polypropylene resin foam. Further, the foam used here is preferably manufactured by an in-mold molding method of expanded particles, but may be manufactured by other methods. The apparent density of the synthetic polymer foam constituting the energy absorbing material is 0.02 to 0.5 g / cm.
³ , preferably 0.03 to 0.3 g / cm ³ . The skin material constituting the shock absorbing bumper of the present invention may be the same as that used in the conventional shock absorbing bumper,
Any material can be used as long as it can be deformed following the deformation of the synthetic polymer foam that serves as the energy absorbing material. Therefore, it is made of synthetic resin or synthetic rubber with some elasticity, and its thickness is 1 to
It is about 10 mm.

The impact absorbing bumper of the present invention has a longitudinal direction of the reinforcement in a position corresponding to the vehicle body mounting member inside the reinforcement, more preferably in the vicinity of the central portion in the longitudinal direction of the reinforcement together with the above position. It is desirable to have transverse reinforcements. The reason is as follows. Recently, in order to improve the habitability in the vehicle and reduce the parking area, it is desired that the vehicle interior is wide and the outer shape is small. Therefore, it is required to reduce the thickness of the bumper, and in order to satisfy this requirement, it is necessary to reduce the deformation amount of the bumper when it receives an impact. This is because if the thickness of the bumper is reduced, the deformation of the bumper immediately leads to the deformation of the vehicle body. Therefore, it is preferable to provide a reinforcing material for reducing the amount of deformation of the bumper when receiving an impact, and it is effective to provide the reinforcing material at two places where the vehicle body mounting member of the reinforcement is provided. . Further, when the bumper is provided in the vicinity of the central portion in the longitudinal direction of the reinforcement together with the portion, the amount of deformation of the bumper when an impact is applied can be further reduced.

The reinforcement provided inside the reinforcement is preferably made of a hollow metal, particularly a pipe-shaped metal such as a steel pipe. And when attaching the reinforcement, on the surface of the energy absorption material of the reinforcement,
A hole may be drilled according to the shape of the cross section of the reinforcing material, the reinforcing material may be inserted, and then both may be welded near the opening of the hole. At this time, the side opposite to the welding side of the reinforcing member does not need to be welded to the vehicle body side inside the reinforcement, but may simply be in contact therewith. Also, since the reinforcing material is welded to the reinforcement, if the reinforcing material is made into a pipe shape and the front-back direction of the vehicle body and the penetrating direction of the vehicle are aligned, the workability during welding is good and when using solid materials. It has the advantage of being lighter.

[0011]

The present invention will now be described in more detail with reference to the drawings. FIG. 1 is a transverse cross-sectional view corresponding to FIG. 4 showing an example of the impact absorbing bumper of the present invention, 1 is an energy absorbing material made of synthetic polymer foam, 2 is a synthetic polymer skin, and 3 is the roll. A hollow reinforcement formed by a bending method such as a forming method, and 8 is a welded joint portion of the reinforcement. The exploded perspective view of the shock absorbing bumper of the present invention is almost the same as that of the conventional shock absorbing bumper shown in FIG. Further, the energy absorbing material 1 and the skin 2 are the same as the conventional product. 2 is an example of a reinforcement provided with a reinforcing material used in the impact absorbing bumper of the present invention, 6 is a pipe-shaped reinforcing material, 7 is a welded joint between the reinforcing material and the reinforcement, and 9 is It is a vehicle body mounting member. The body mounting member 9 shown here
Is the same as the conventional product.

Comparing FIG. 1 and FIG. 4, it can be seen that the reinforcement shown in FIG. 4 has two welding margins and is heavier than that shown in FIG. Further, the reinforcement used in the present invention is welded at the joint portion 8. This welding only needs to weld the end portions of the formed metal plates together, but if the end portions are overlapped and welded, the strength is increased. To increase. Even if the end portions are overlapped with each other, the welding allowance is significantly smaller than the welding allowance of the conventional reinforcement, so that the weight of the reinforcement is significantly reduced as compared with the conventional product. In the reinforcement shown in FIG. 2, the reinforcing member 6 is provided in the portion where the vehicle body attaching member 9 is attached and in the vicinity of the central portion in the longitudinal direction,
The reinforcement and the reinforcement are welded at the 7th part. The reinforcing material has an outer diameter of 20 to 100 mm and a wall thickness of 2-1.
It is a 0 mm steel pipe, and the end on the side not welded to the reinforcement is in contact with the surface of the reinforcement on which the welded joint 8 is formed. Further, since the reinforcement is provided with the reinforcing material also in the central portion, the rigidity of the central portion is enhanced in the impact absorbing bumper using the reinforcing material.

[0013]

The impact absorbing bumper of claim 1 has a lower price and higher rigidity than the ordinary impact absorbing bumpers currently used. In the shock absorbing bumper according to the second aspect, the bumper can be made thin because the deformation when receiving a shock is small. The impact-absorbing bumper of claim 3 is less deformed than the above in the impact-absorbing bumper included in claim 2 when it receives an impact, and therefore the deformation is less than that in the impact-absorbing bumper included in claim 2. Further, the thickness can be reduced. The shock absorbing bumper according to claim 4 is
Since the reinforcing member made of a hollow metal is used, when compared by the same amount of deformation when receiving a shock, it is the lightest shock absorbing bumper among the shock absorbing bumpers of claims 2 and 3.

[Brief description of drawings]

FIG. 1 is an example of a cross-sectional view of a shock absorbing bumper of the present invention.

FIG. 2 is a perspective view showing an example of a reinforcement provided with a reinforcing material used in the impact absorbing bumper of the present invention.

FIG. 3 is an exploded perspective view showing an outline of a conventional general shock absorbing bumper.

FIG. 4 is a transverse cross-sectional view of a central portion in the longitudinal direction of the shock absorbing bumper shown in FIG.

[Explanation of symbols]

1 Energy Absorbing Material 2 Skin 3 Reinforcement 4 Welding Allowance 5 Side of Reinforcement 6 Reinforcement 7 Weld of Reinforcement 8 Joint Weld of Reinforcement 9 Body Attachment

Claims (4)

[Claims] 1. A shock absorbing bumper comprising a metal reinforcement provided with a vehicle body mounting member, a skin material, and an energy absorbing material made of a synthetic polymer foam interposed between the two. An impact-absorbing bumper characterized in that the reinforcement is hollow and manufactured by bending. 2. The shock absorbing bumper according to claim 1, wherein a reinforcing member that traverses the longitudinal direction of the reinforcement is provided at a position corresponding to the vehicle body mounting member inside the reinforcement. 3. The shock absorbing bumper according to claim 2, wherein a reinforcing member that traverses the longitudinal direction of the reinforcement is also provided near the center in the longitudinal direction inside the reinforcement. 4. The shock absorbing bumper according to claim 2, wherein the reinforcing material is formed of a hollow metal.