JP3794966B2 - Bumper reinforcement structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a front and rear structure of a vehicle body such as a passenger car, and more particularly to a bumper reinforcement that extends in the width direction at the front or rear portion of the vehicle body and is fixed to an end portion of a side member.
[0002]
[Prior art]
In a vehicle body such as a passenger car, a bumper reinforcement is fixed to the front end or rear end of the side member via a bumper stay so as to extend in the vehicle body width direction. The bumper reinforcement is designed to protect the vehicle body by receiving the impact when it collides with an obstacle. Some bumper reinforcement materials use metal pipes such as electric cross-section pipes made of steel and have a rectangular cross section so that the cost can be reduced compared to extruded aluminum. However, the bumper reinforcement is installed so as to be stretched between the side members on both sides of the vehicle, and is free in the middle. In the case of an electric-welded pipe, the interior is completely hollow and the strength is insufficient. Due to the large bending moment, it could easily buckle and cause damage to the vehicle. Therefore, in order to reinforce the intermediate portion of the bumper reinforcement having a rectangular cross section, Japanese Patent Laid-Open No. 2001-322517 discloses a reinforcement member provided on the front surface of the bumper reinforcement. This reinforcing member is formed by concentrating the middle portion of the U-shaped plate material in a concave shape toward the front surface of the bumper reinforcement. In the event of a collision, the drawn portion behaves so as to increase the rigidity against the compressive load, thereby reinforcing the bumper reinforcement.
[0003]
[Problems to be solved by the invention]
The technique disclosed in Japanese Patent Laid-Open No. 2001-322517 aims to reinforce the bumper reinforcement by providing a reinforcing member on the front surface. However, in recent years, from the viewpoint of protecting pedestrians, the foamed polyurethane material for cushioning, which has been provided on the front of the bumper reinforcement, has been made much thicker, and legislation in that direction has been promoted. Yes. Therefore, there is a tendency for the front surface of the bumper reinforcement to be eliminated, and there has been a demand for an alternative means that does not have a large occupied space in front of the bumper reinforcement. In addition, the entire length of the vehicle is extended by the reinforcing member on the front surface of the bumper reinforcement, which causes problems in terms of driving performance and vehicle space.
[0004]
The present invention has been made in view of such a current situation, and provides a novel structure that can reinforce the bumper reinforcement as needed without substantially occupying the space in front of the bumper reinforcement. Objective.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, the bumper reinforcement composed of a metal tube having a rectangular cross section that is fixed to the end of the side member while extending in the width direction of the vehicle body, and at least one reinforcement that is fixed to the bumper reinforcement. In the structure comprising the members, the at least one reinforcing member has a U-shaped cross-section opening on the surface facing the bumper reinforcement in the vertical direction of the vehicle body, and the reinforcing member has a bumper with the U-shaped opening in the cross-sectional shape. The reinforcement member is inserted into the bumper reinforcement from above or below toward the outer upper surface or the lower surface of the reinforcement, and the reinforcing member is a bumper rain while leaving the opening at a predetermined height with respect to the opposite surface of the bumper reinforcement. It is welded to the force and the reinforcing member is extended in the longitudinal direction at the center of the bumper reinforcement Bumper reinforcement reinforcing structure characterized is provided.
[0006]
The operation and effect of the invention of claim 1 will be explained. The reinforcing member having a U-shaped cross section has a bumper reinforcement so that its opening faces the upper surface or the lower surface of the bumper reinforcement leaving a cavity of a predetermined height. It is arranged at the center of the. Therefore, the load applied to the front surface of the bumper reinforcement at the time of collision can be distributed not only to the bumper reinforcement but also to the reinforcing member at the height of the cavity. Relieve stress concentration. Therefore, the deformation amount of the bumper reinforcement against the collision can be relatively reduced, buckling can be prevented, and the vehicle body can be protected. Unlike the conventional reinforcing member, the occupied area in front of the vehicle body can be substantially zero.
[0007]
According to a second aspect of the present invention, there is provided a bumper reinforcement characterized in that in the first aspect of the present invention, a pair of reinforcing members are provided with a metal tube interposed therebetween.
[0008]
The operation and effect of the invention of claim 2 will be described. Since the reinforcing members are provided above and below, the load distribution effect by the reinforcing members can be further enhanced.
[0009]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the metal pipe is bent at both ends fixed to the side member toward the vehicle body, and the reinforcing member is a metal pipe. A bumper reinforcement is provided which extends to the bent portion.
[0010]
The operation and effect of the invention of claim 3 will be described. In the structure in which the bumper reinforcement is bent at both ends, the reinforcing member can reinforce the bent portion.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiment of the present invention will be described in the case where a bumper reinforcement is provided at the front end of the side member. However, the present invention can also be applied to a bumper reinforcement at the rear end of the side member. In FIG. 1, reference numeral 10 denotes a side member, which is provided on both sides of the vehicle body. The rear end of the bumper stay 12 is fixed to the front end of the side member 10. Reference numeral 14 denotes a bumper reinforcement, which is composed of a steel pipe having a rectangular cross section. As the steel pipe, it is preferable that the steel pipe is constituted by an electric-welded pipe in view of cost. An electric sewing tube is formed by forming a plate material into a rectangular cross section by a roll and welding opposite end surfaces by energization to form a pipe material. This invention is not limited to ERW pipes but can be applied to bumper reinforcements made of aluminum material. However, in the case of aluminum materials, a cross-sectional shape (“day” or “ Since it is easy to reinforce by molding into a "" -shaped cross-sectional shape, etc.) and a reinforcing member is often unnecessary, the present invention has a completely hollow interior like an electric sewing tube. It is more suitable for the metal steel pipe which requires a reinforcement member separately.
[0012]
Both ends 14-1 of the bumper reinforcement 14 are bent rearward of the vehicle body, and the front end of the bumper stay 12 is fixed to the bent portion 14-1. FIG. 2 (a) shows a rectangular cross-sectional shape of the bumper reinforcement 14 of FIG. 1, a front surface 14A facing the front of the vehicle body, a rear surface 14B facing the rear of the vehicle body, an upper surface 14C facing the upper side of the vehicle body, And a bottom surface 14D facing the lower side of the vehicle body. The front end of the bumper stay 12 is fastened to the rear surface 14B of the bumper reinforcement 14 with a bolt (not shown).
[0013]
In this embodiment, one reinforcing plate 16 as a reinforcing member of the present invention is provided on the upper side of the bumper reinforcement and has a U-shaped cross section. As shown in FIG. It extends in the longitudinal direction of the force 14. In the U-shaped cross-sectional shape of the reinforcing plate 16 shown in FIG. 2 (a), the reinforcing plate 16 includes a front surface 16A, a rear surface 16B, and an upper surface 16C. Is forming. The opening 16-1 faces downward, that is, faces the upper surface 14C of the bumper reinforcement 14, and the cavity 18 is formed between the opposing surfaces 14C, 16C of the bumper reinforcement 14 and the reinforcing plate 16 in the vertical direction. The height of the cavity 18, that is, the distance between the opposing surfaces 14C and 16C is represented by x. The front surface 14A of the bumper reinforcement and the front surface 16A of the reinforcement plate, which are opposed surfaces of the bumper reinforcement 14 and the reinforcement plate 16 on the front side of the vehicle body, that is, the opposite surfaces in the vehicle body front-rear direction, are spaced along the longitudinal direction. It is welded at an appropriate number of places, and the weld is indicated at 20. Similarly, the opposite surface of the bumper reinforcement 14 and the reinforcing plate 16 on the rear side of the vehicle body, that is, the rear surface 14B of the bumper reinforcement that is the opposing surface in the longitudinal direction of the vehicle body and the rear surface 16B of the reinforcing plate are spaced along the longitudinal direction. Welding is carried out at an appropriate number of locations 20 '.
[0014]
In FIG. 3 showing the bumper reinforcement 14 as viewed from above, when the vehicle collides with an obstacle A in the direction of the arrow f, the rear of the vehicle body (in the direction of the arrow g in FIG. 2) faces the center of the bumper reinforcement in the vehicle width direction. Added load. In the present invention, the reinforcing plate 16 is installed so that a cavity 18 (height = x) is formed in the U-shaped opening as shown in FIG. The upper surface 14C of the force 14 functions like a bumper reinforcement of the shape of the “day” or “eye” cross section, and the load applied to the center of the bumper reinforcement 14 in the vehicle width direction due to the collision is further increased. It can be dispersed over a wide range and the stress concentration at the center of the bumper reinforcement can be alleviated. Therefore, the bumper reinforcement 14 can have a structure that is strong against buckling. In the bumper reinforcement 14, the value of the distance x between the opposing surfaces 14 </ b> C and 16 </ b> C in the vertical direction with the reinforcing plate 16 is appropriately set so as to obtain a desired reinforcing performance.
[0015]
Next, as shown in FIG. 3, a model experiment by the finite element method is performed when the bumper reinforcement 14 reinforced by the reinforcing plate 16 is made to collide with the obstacle A at a predetermined speed as indicated by an arrow f. did. The solid line (a) in FIG. 4 schematically shows the elapsed time-deformation amount characteristic of the structure of the present invention shown in FIG. 2 (a), and the deformation amount from the start of the collision returns to the initial value after reaching the maximum, This means that no buckling occurs. That is, a force in the direction of arrow g (rear body) in FIG. 2 (a) is applied to the bumper reinforcement 14 due to the collision. In the present invention, the reinforcing plate 16 is formed in the bumper reinforcement 14 in the height direction and the cavity 18 is formed in the height direction. It is possible to make the front part of the reinforcing plate height x effectively function as a reinforcing material, and the impact load is distributed over a wider range. It is possible to provide. On the other hand, the broken line B in FIG. 4 indicates the case where there is no space in the U-shaped opening of the cross section of the reinforcing plate as shown in FIG. The result of the model experiment by the finite element method under the same condition as FIG. 2 (a) in the case of the distance x = 0 between the opposing surfaces is schematically shown. In this case, the deformation amount from the start of the collision maintains the maximum. This means that buckling occurs and the bumper reinforcement breaks at the center. That is, in the case of FIG. 2B, the height above the bumper reinforcement 114 does not substantially increase even if the reinforcing plate 116 is provided, and therefore stress cannot be distributed at the central portion of the bumper reinforcement. However, stress concentration occurs due to the collision at a lower speed, and a sufficient reinforcing function cannot be obtained.
[0016]
FIG. 5 shows a bumper reinforcement according to a second embodiment of the present invention. In this embodiment, reinforcing plates 16 and 16 ′ having U-shaped cross sections are provided above and below the bumper reinforcement 14. The mounting structure of the reinforcing plates 16 and 16 'with respect to the bumper reinforcement 14 is the same as that shown in FIG. 2 (a), and the U-shaped openings of the reinforcing plates 16 and 16' face the upper and lower surfaces of the bumper reinforcement 14. In addition, cavities 18 and 18 'having a predetermined height are formed between the opposing upper and lower surfaces, and opposing opposing surfaces in the longitudinal direction of the vehicle body are fixed at the welded portions 20 and 20'. By providing the reinforcing plates 16 and 16 'above and below the bumper reinforcement 14, the central portion of the bumper reinforcement 14 can be reinforced more effectively.
[0017]
FIG. 6 shows a third embodiment. In this embodiment, the reinforcing plate 16 is provided with bent portions 16-1 at both ends, and the reinforcing plate 16 is provided at the bent portions 14-1 at both ends of the bumper reinforcement 14. It extends to the longitudinal direction of the bumper reinforcement. Bending of the bent portions 16-1 at both ends of the reinforcing plate 16 is performed prior to welding to the bumper reinforcement 14, and at this time, the bending angle of the bent portions 16-1 of the reinforcing plate 16 is set at both ends of the bumper reinforcement 14. The bent angle of the bent portion 14-1 is matched with the bent portion 14-1, and it is possible to mount and weld the plate by simply applying the reinforcing plates 16, 16 'regardless of the bent shape of the bumper reinforcement 14. In this embodiment, the bent portion of the bumper reinforcement can be reinforced by the reinforcing plate 16. Further, it is possible to reinforce only by setting the mounting position of the reinforcing plate up and down to a necessary portion without excessively reinforcing the entire bumper reinforcement.
[Brief description of the drawings]
FIG. 1 is a perspective view of a bumper reinforcement having a reinforcing plate of the present invention.
2A is a cross-sectional view taken along the line II-II in FIG. 1, and FIG. 2B is an unfavorable configuration in which the reinforcing plate is in close contact with the opposing surface of the bumper reinforcement. Indicates.
FIG. 3 is a top view of the bumper reinforcement of the present invention.
FIG. 4 is a graph schematically showing a time-deformation amount characteristic in a model experiment by a finite element method regarding the bumper reinforcement of the present invention.
FIG. 5 is a perspective view of a bumper reinforcement according to another embodiment of the present invention.
FIG. 6 is a perspective view of a bumper reinforcement according to still another embodiment of the present invention.
[Explanation of symbols]
10 ... side member 12 ... bumper stay 14 ... bumper reinforcement 16 ... reinforcing plate 18 ... cavity
20, 20 '... welded part x ... cavity height

Claims (3)

A structure comprising a bumper reinforcement made of a metal tube having a rectangular cross section that is fixed to an end of a side member while extending in the width direction of the vehicle body, and at least one reinforcing member fixed to the bumper reinforcement. The reinforcing member has a U-shaped cross-section opening on the surface facing the bumper reinforcement in the vertical direction of the vehicle body, and the reinforcing member has the U-shaped opening of the cross-section facing the outer upper surface or the outer lower surface of the bumper reinforcement. The reinforcing member is inserted into the bumper reinforcement from above or below , and the reinforcing member is welded and fixed to the bumper reinforcement while leaving a cavity having a predetermined height with respect to the opposing surface of the bumper reinforcement, and the reinforcing member is A bumper reinforcement that extends in the longitudinal direction at the center of the bumper reinforcement Reinforcing structure. The bumper reinforcement structure according to claim 1, wherein a pair of reinforcement members are provided with the bumper reinforcement interposed therebetween. In the invention according to claim 1 or 2, the bumper reinforcement material is bent toward the vehicle body at both ends fixed to the side member, and the reinforcing member extends to the bent portion of the metal tube material. Bumper Reinforce that is characterized by

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