Bumper reinforcement

Abstract

To alleviate transmission of a front collision load input to an end position in a vehicle width direction.SOLUTION: The bumper reinforcement 1 includes a front wall part 2 facing the front of the vehicle and extending in the vehicle width direction, a rear wall part facing the rear of the vehicle and extending in the vehicle width direction, and a lateral wall part 10 extending in the vehicle width direction and connecting the front wall part 2 and the rear wall part. In addition, the bumper reinforcement 1 includes the hole portion 50 provided in the 10e portion of the lateral wall portion 10 at the end position in the vehicle-width direction. Then, in the bumper reinforcement 1, the hole portion 50 is deformed based on the collision load input to the front of the hole portion 50, and the front sidewall surface 50sf of the hole portion 50 retreats.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a bumper reinforcement. [Background technology]

[0002] Most bumper reinforcements, which are structural members of the front of a vehicle, have a rectangular cylindrical outer shape extending in the vehicle width direction. Such bumper reinforcements typically have a bow-shaped curve at their ends in the vehicle width direction, which are curved more toward the rear of the vehicle than the center in the vehicle width direction, in order to efficiently absorb collision loads input from the diagonally front of the vehicle. Furthermore, as shown in Patent Document 1, for example, a conventional bumper reinforcement has a structure in which the front side of the bow-shaped rectangular cylindrical shape is diagonally cut out at the end in the vehicle width direction. By adopting such a configuration, it is possible to reduce the thickness of the bumper reinforcement in the vehicle longitudinal direction at the end in the vehicle width direction, where it is difficult to secure installation space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4413129 Summary of the Invention [Problem to be solved by the invention]

[0004] Furthermore, when a collision load is applied from the front of the vehicle, the bumper reinforcement has the function of transmitting the front collision load to a rear crash box. In particular, it is common for vehicles to have crash boxes located behind the bumper reinforcement at the end positions in the vehicle width direction. Therefore, one of the important issues for the bumper reinforcement is how to transmit the front collision load applied to the end positions in the vehicle width direction. [Means for solving the problem]

[0005] The bumper reinforcement according to the present invention comprises a front wall portion facing the front of the vehicle and extending in the vehicle width direction, a rear wall portion facing the rear of the vehicle and extending in the vehicle width direction, a lateral wall portion extending in the vehicle width direction to connect the front wall portion and the rear wall portion, and a hole portion provided at an end position of the lateral wall portion in the vehicle width direction, and the hole portion deforms based on a collision load input in front of the hole portion, causing a front wall surface of the hole to retreat.

[0006] According to the above configuration, during the deformation of the hole provided in the side wall portion, a collision load input from the front side of the vehicle to the end position of the hole in the vehicle width direction can be absorbed. In particular, by retracting the front wall surface, it is possible to effectively suppress the direct transmission of the load that is transmitted rearward by the bumper reinforcement due to the input of the front collision load. This makes it possible to mitigate the front collision load transmitted rearward. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the transmission of a front collision load input to an end position in the vehicle width direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of the bumper reinforcement. [Figure 2] FIG. 2 is a cross-sectional view of the bumper reinforcement. [Figure 3] FIG. 3 is an enlarged perspective view of the vicinity of an end position of the bumper reinforcement in the vehicle width direction. [Figure 4] FIG. 4 is an enlarged plan view of the vicinity of an end position in the vehicle width direction of the bumper reinforcement. [Figure 5] FIG. 5 is a cross-sectional view of the bumper reinforcement in the vicinity of the notch and the reinforcing plate provided at the end position in the vehicle width direction. [Figure 6] FIG. 6 is a cross-sectional view of the bumper reinforcement in the vicinity of a hole provided at an end position in the vehicle width direction. [Figure 7] FIG. 7 is an explanatory diagram of the offset collision test. [Figure 8] FIG. 8 is an explanatory diagram of a case where a collision load is input to the front of the hole. [Figure 9] FIG. 9 is an explanatory diagram of a hole portion that is deformed by input of a front collision load. [Figure 10] FIG. 10 is a graph showing the change in load during a collision. [Figure 11] FIG. 11 is a graph showing an example of test results regarding load changes during a collision. [Figure 12] FIG. 12 is a plan view of the bumper reinforcement in the second embodiment. [Figure 13] FIG. 13 is an explanatory diagram of a hole in the second embodiment, and a case where a collision load is input in front of the hole. [Figure 14] FIG. 14 is an explanatory diagram of a hole portion that is deformed by input of a front collision load in the second embodiment. [Figure 15] FIG. 15 is a graph showing an example of test results regarding load changes during a collision in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] A first embodiment of a bumper reinforcement will be described below with reference to the drawings. As shown in FIG. 1, the bumper reinforcement 1 of this embodiment has a substantially rectangular cylindrical shape extending in the vehicle width direction (left-right direction in FIG. 1) and is disposed in the front of a vehicle (not shown), thereby functioning as a structural member of the vehicle.

[0010] <Bumper reinforcement wall structure> 1 and 2, the bumper reinforcement 1 of this embodiment includes a front wall portion 2 that faces the front of the vehicle (upper side in FIG. 1, left side in FIG. 2) and extends in the vehicle width direction. The bumper reinforcement 1 also includes a rear wall portion 3 that faces the rear of the vehicle (lower side in FIG. 1, right side in FIG. 2) and extends in the vehicle width direction. The bumper reinforcement 1 of this embodiment also includes a plurality of lateral wall portions 10 that connect the front wall portion 2 and the rear wall portion 3 together, extending in the vehicle width direction.

[0011] 2, the bumper reinforcement 1 of this embodiment includes an upper wall portion 11 that connects an upper end portion 2a of the front wall portion 2 and an upper end portion 3a of the rear wall portion 3, and a lower wall portion 12 that connects a lower end portion 2b of the front wall portion 2 and a lower end portion 3b of the rear wall portion 3. The bumper reinforcement 1 also includes an intermediate wall portion 13 that connects the front wall portion 2 and the rear wall portion 3 at a position between the upper wall portion 11 and the lower wall portion 12 in the vertical direction.

[0012] That is, in the bumper reinforcement 1 of this embodiment, the upper wall portion 11, the lower wall portion 12, and the intermediate wall portion 13 extend in the vehicle width direction and also in the vehicle front-rear direction, thereby forming lateral wall portions 10 that extend in the horizontal direction. Furthermore, each of these lateral wall portions 10 is arranged as a vertical wall portion 15 that extends in the up-down direction, generally perpendicular to the front wall portion 2 and the rear wall portion 3. As a result, the bumper reinforcement 1 of this embodiment has a square cylindrical shape with a cross section that is generally in the shape of a Japanese character "sun".

[0013] <Bumper reinforcement wall structure> As shown in FIG. 1 , the bumper reinforcement 1 of this embodiment has a bow-shaped curve in which both end positions 1e, 1e in the vehicle width direction are curved toward the vehicle rear from a central position 1c in the vehicle width direction. Specifically, the bumper reinforcement 1 of this embodiment is formed using an extruded material made of, for example, an aluminum alloy. That is, the bumper reinforcement 1 is formed into a long rectangular tubular shape having a cross section generally shaped like a Japanese character "sun" by extrusion molding, and then the bow-shaped curve is imparted by bending. Furthermore, the bumper reinforcement 1 of this embodiment has crash boxes 20, 20 disposed behind the both end positions 1e, 1e in the vehicle width direction. Note that in the vehicle, for example, a side member (not shown) or the like is given the function of such crash boxes 20. Thus, the bumper reinforcement 1 of this embodiment is configured to efficiently absorb a collision load input to the end positions 1e, 1e in the vehicle width direction by utilizing the bow-shaped curve.

[0014] <Front cutout and front plate> As shown in Figures 1 and 3 to 5, the bumper reinforcement 1 of this embodiment has front cutouts 30, 30 at each end position 1e, 1e on both sides in the vehicle width direction, which are provided by obliquely cutting out the front portion of the vehicle of its elongated, approximately rectangular cylindrical shape.

[0015] Specifically, each of these front cutouts 30 is formed by cutting out the front wall 2, the upper wall 11, the lower wall 12, and the middle wall 13 at an end position 1e in the vehicle width direction of the bumper reinforcement 1. In other words, each of these front cutouts 30 is configured by cutting out the vehicle front side of end positions 2e, 10e of the front wall 2 and each of the lateral wall portions 10. Furthermore, each of these front cutouts 30 has a cutout end surface 10x of each lateral wall portion 10 that forms the front cutout 30 gradually recessed toward the vehicle rear from the inner side to the outer side in the vehicle width direction of the bumper reinforcement 1 (from the right side to the left side in FIG. 4 ). As a result, the bumper reinforcement 1 of this embodiment is configured so that the thickness of its elongated, approximately rectangular cylindrical shape in the vehicle front-rear direction gradually becomes thinner from the inner side to the outer side in the vehicle width direction at each end position 1e on both sides in the vehicle width direction.

[0016] The bumper reinforcement 1 of this embodiment also includes a pair of front plates 35, 35 fixed to the front cutouts 30, 30 at the end positions 1e, 1e on both sides in the vehicle width direction.

[0017] More specifically, in the bumper reinforcement 1 of this embodiment, each of these front plates 35 has a substantially flat plate-like outer shape. Furthermore, each of these front plates 35 has a substantially flat plate-like back surface 35sb side fixed to the cutout end surface 10x of each of the lateral wall portions 10 that constitutes each of the front cutout portions 30, for example, by welding. As a result, the bumper reinforcement 1 of this embodiment is configured so that each of these front plates 35 serves as a reinforcing member 40 to reinforce the end position 1e in the vehicle width direction where the front cutout portion 30 is provided.

[0018] Specifically, in the bumper reinforcement 1 of this embodiment, the front plate 35 is fixed to the cutout end face 10x in a manner that covers the front cutout portion 30 that opens toward the front side of the vehicle. As a result, the bumper reinforcement 1 of this embodiment is configured to replace the front wall portion 2 of the portion that becomes the cutout end position 2e due to the formation of the front cutout portion 30 at the end position 1e in the vehicle width direction.

[0019] More specifically, in the bumper reinforcement 1 of this embodiment, each of these front plates 35 has a bent shape at both end portions in the vehicle width direction. Furthermore, in the bumper reinforcement 1 of this embodiment, in a state in which the front plate 35 is fixed to the front cutout portion 30 as described above, the bent shape imparted to the inner end portion 35eb in the vehicle width direction is fixed to the front surface 2sf of the front wall portion 2 facing the front side of the vehicle. Thus, the bumper reinforcement 1 of this embodiment is configured so that the front plates 35, 35 are fixed more stably to the front cutout portions 30, 30 provided at the end positions 1e, 1e on both sides in the vehicle width direction.

[0020] <Hole in the side wall> 4 and 6, the bumper reinforcement 1 of this embodiment has holes 50, 50 provided in the upper wall portion 11 and the lower wall portion 12 at end positions 1e in the vehicle width direction. Specifically, these holes 50, 50 are provided at end positions 10e in the vehicle width direction of each lateral wall portion 10 formed by the upper wall portion 11 and the lower wall portion 12, respectively, in a manner of penetrating the upper wall portion 11 and the lower wall portion 12. In the bumper reinforcement 1 of this embodiment, such a hole 50 is not provided in the intermediate wall portion 13. Furthermore, in the bumper reinforcement 1 of this embodiment, the holes 50, 50 provided in the upper wall portion 11 and the lower wall portion 12 have approximately the same hole shape. In the bumper reinforcement 1 of this embodiment, these holes 50, 50 are arranged at approximately the same positions in the upper wall portion 11 and the lower wall portion 12 that overlap in the vertical direction.

[0021] More specifically, in the bumper reinforcement 1 of this embodiment, each hole 50 is provided at an end position 10e in the vehicle width direction of the lateral wall portion 10, at a position on the vehicle front side that is near the front wall portion 2. Each hole 50 has an elongated hole shape extending in the vehicle width direction. Specifically, each hole 50 of this embodiment has an elongated hole shape in which a front wall surface 50sf and a rear wall surface 50sr extending in the vehicle width direction are arranged substantially parallel to each other. Furthermore, each hole 50 has an inner end portion 50eb in the vehicle width direction at a position in the vehicle width direction that is substantially equal to an inner end portion 35eb in the vehicle width direction of the front plate 35 fixed to the front cutout portion 30. Thus, in the bumper reinforcement 1 of this embodiment, each hole 50 extends from the inner side to the outer side in the vehicle width direction behind the front plate 35.

[0022] Moreover, the bumper reinforcement 1 of this embodiment is configured such that an outer end 50ea in the vehicle width direction of each of these hole portions 50 is located on the vehicle rear side relative to an inner end 50eb in the vehicle width direction. In the bumper reinforcement 1 of this embodiment, longitudinal end faces 50es, 50es of each hole portion 50 formed by the outer end 50ea and the inner end 50eb form curved surfaces S that are continuous with the front wall surface 50sf and the rear wall surface 50sr, respectively.

[0023] <Deformation of the hole due to a frontal collision load input to the end position in the vehicle width direction> As shown in Figures 7 to 9, in the event of a so-called offset collision in which the vehicle and an obstacle collide while being shifted in the vehicle width direction, a collision load is input from the front side of the vehicle to the end position 1e of the bumper reinforcement 1 in the vehicle width direction.

[0024] In the bumper reinforcement 1 of this embodiment, the hole 50 provided at the end position 10e in the vehicle width direction in the lateral wall portion 10 is deformed based on the front collision load input during such an offset collision. Specifically, in the bumper reinforcement 1 of this embodiment, the front wall surface 50sf of the hole 50 is moved backward based on the collision load input in front of the hole 50. The bumper reinforcement 1 of this embodiment is configured to mitigate the transmission of the front collision load input to the end position 1e in the vehicle width direction by the deformation of the hole 50.

[0025] 7 to 9 show aspects of an offset collision test that reproduces the above-described offset collision. That is, in the offset collision test shown in each of these figures, a test barrier 60 collides with the bumper reinforcement 1 at a position where the inner end 35eb in the vehicle width direction of the front plate 35 fixed to the front cutout 30 is positioned. Then, in the bumper reinforcement 1 of this embodiment, the holes 50, 50 formed in the upper wall portion 11 and the lower wall portion 12 that constitute the lateral wall portion 10 are deformed based on the front collision load input to the end position 1e in the vehicle width direction.

[0026] More specifically, during an offset collision, after the vehicle first collides with an obstacle, the collision position of the vehicle with the obstacle gradually shifts from the inside to the outside in the vehicle width direction as the collision progresses. In order to reproduce this, the offset collision test shown in Figures 7 to 9 is also configured so that the input position of the collision load on the bumper reinforcement 1 moves relatively from the inside to the outside in the vehicle width direction.

[0027] 7 to 9, the test barrier 60 appears to move relatively toward the rear of the vehicle while being displaced from the inside toward the outside in the vehicle width direction of the bumper reinforcement 1. In addition, in Fig. 8, the "arrow" shown by the dashed line indicates the traveling direction of the barrier 60 that collided with the bumper reinforcement 1 at this time, that is, the relative movement direction of the input position of the collision load to the bumper reinforcement 1 as the collision progresses. In addition, the "two-dot chain line" in Fig. 9 indicates the position of the barrier 60 that appears to have moved relatively from the inside toward the outside in the vehicle width direction, and the retreated position of the front wall surface 50sf of the hole portion 50 that has been deformed as a result.

[0028] That is, in the bumper reinforcement 1 of this embodiment, the input position of the collision load moves relatively in front of the hole portion 50, which has an elongated hole shape extending in the vehicle width direction and is disposed behind the front plate 35, along the extending direction of this hole portion 50. As a result, the bumper reinforcement 1 of this embodiment is configured so that the hole portion 50 deforms in such a manner that the front wall surface 50sf thereof gradually retreats.

[0029] More specifically, in the bumper reinforcement 1 of the present embodiment, the front wall surface 50sf, which has been set back by the deformation of the hole portion 50, comes into contact with the rear wall surface 50sr of the hole portion 50. After the setback front wall surface 50sf comes into contact with the rear wall surface 50sr, the hole portion 50 is further deformed, and the front wall surface 50sf and the rear wall surface 50sr of the hole portion 50 come into contact with each other in a state where they are in contact with each other over substantially the entire surfaces.

[0030] That is, as described above, during an offset collision, the input position of the collision load with respect to the end position 1e in the vehicle width direction is displaced relatively from the inner side toward the outer side in the vehicle width direction. Moreover, in the bumper reinforcement 1 of this embodiment, the hole 50 provided in the lateral wall portion 10 at the end position 1e in the vehicle width direction also has an elongated hole shape extending in the vehicle width direction. Therefore, even after the front wall surface 50sf, which has been retracted due to the deformation of the hole 50, comes into contact with the rear wall surface 50sr, the input position of the collision load moves along the extending direction of the hole 50, and the contact areas of the front wall surface 50sf and the rear wall surface 50sr gradually increase. Thus, in the bumper reinforcement 1 of this embodiment, the front wall surface 50sf and the rear wall surface 50sr of the hole 50 are in contact with each other over substantially the entire surfaces.

[0031] In the bumper reinforcement 1 of this embodiment, the front collision load input to the end position 1e in the vehicle width direction is absorbed in the process of deformation of the hole 50 provided in the side wall portion 10. In this way, the bumper reinforcement 1 of this embodiment is configured to mitigate the transmission of the front collision load to the crash box 20 arranged behind the bumper reinforcement 1.

[0032] <Operation of this embodiment> 10, if the side wall 10 does not have the hole 50 at the end position 10e in the vehicle width direction, the load F transmitted to the rear crash box 20 reaches its maximum value Fmax in a short time. Specifically, in this case, after the front collision load is input, the load F transmitted to the rear crash box 20 increases approximately linearly in proportion to the increase in the stroke X, which is the value of the relative movement amount indicating the progression of the collision. Then, by transmitting a large load F rearward in such a short time, there is a possibility that the impact absorption function of the crash box 20 will not be effectively utilized.

[0033] However, as shown by the waveform M in Fig. 10 , in the bumper reinforcement 1 of this embodiment having the hole 50 at the end position 10e of the lateral wall portion 10 in the vehicle width direction, the load F transmitted rearward is alleviated in the process of deformation of the hole 50. This makes it possible to effectively utilize the impact absorbing function of the crash box 20 arranged rearward of the bumper reinforcement 1.

[0034] Specifically, when the value of the stroke X, which indicates the progress of the collision, reaches "X1," the hole 50 begins to deform with the front wall surface 50sf retreating. Next, when the value of the stroke X reaches "X2," the front wall surface 50sf, which has retreated due to the deformation of the hole 50, comes into contact with the rear wall surface 50sr of the hole 50. Furthermore, as the value of the stroke X exceeds "X2," the contact area between the front wall surface 50sf and the rear wall surface 50sr of the deformed hole 50 gradually increases. Then, by the time the value of the stroke X reaches "X3," the front wall surface 50sf and the rear wall surface 50sr of the hole 50 come into contact with each other over substantially the entire surface.

[0035] As a result, after the value of the stroke X, which indicates the progression of the collision, reaches "X1," the value of the load F transmitted rearward by the bumper reinforcement 1 due to the input of the front collision load is suppressed for a predetermined time t until the value of this stroke X reaches "X2." Furthermore, as the value of the stroke X exceeds "X2," the value of the load F transmitted rearward by the bumper reinforcement 1 increases again. Then, thereafter, when the value of the stroke X reaches "X3," the value of the load F reaches a maximum value Fmax.

[0036] As described above, in the bumper reinforcement 1 of the present embodiment, as the hole 50 deforms based on a collision load input forward, the contact state between the front wall surface 50sf and the rear wall surface 50sr in the deformed hole 50 changes. Furthermore, the front collision load is absorbed based on the deformation of the hole 50 according to the contact state between the front wall surface 50sf and the rear wall surface 50sr. In other words, the direct transmission of the load F that is transmitted rearward due to the input of the front collision load is suppressed. As a result, in the section where the value of the stroke X increases from "X1" to "X3," the front collision load transmitted rearward by the bumper reinforcement 1 is alleviated by the total amount of the load F whose direct transmission is suppressed. In FIG. 10 , the area of ​​the rectangle surrounded by the waveforms L and M in the section from "X1" to "X3" corresponds to the "total amount of the load F whose direct transmission is suppressed."

[0037] <Test Results> Fig. 11 is a graph showing an example of test results relating to changes in load during a collision. In Fig. 11, waveform M0 is a preferred example waveform obtained by simulation for a load F transmitted rearward based on a frontal collision load when the frontal collision load is input to an end position 1e in the vehicle width direction. As shown by waveform M1 in the same figure, the effect of mitigating the frontal collision load transmitted rearward can also be confirmed from the actual test results.

[0038] Specifically, in the example shown in the waveform M1, when the value of the stroke X reaches "X4," the hole 50 begins to deform. Furthermore, when the value of the stroke X reaches "X5," the front wall surface 50sf of the deformed hole 50 comes into contact with the rear wall surface 50sr of the hole 50. Furthermore, when the value of the stroke X reaches "X6," the front wall surface 50sf and the rear wall surface 50sr of the hole 50 come into contact with each other over substantially the entire surface. As a result, compared to the waveform M0 shown for reference, the slope until the load F transmitted rearward reaches its maximum value is gentler, but the front collision load transmitted rearward by the bumper reinforcement 1 is alleviated during the process of deformation of the hole 50 as described above.

[0039] <Effects of this embodiment> Next, the effects of this embodiment will be described. (1) The bumper reinforcement 1 includes a front wall portion 2 facing the front of the vehicle and extending in the vehicle width direction, a rear wall portion 3 facing the rear of the vehicle and extending in the vehicle width direction, and a lateral wall portion 10 extending in the vehicle width direction to connect the front wall portion 2 and the rear wall portion 3. The bumper reinforcement 1 also includes a hole portion 50 provided at an end position 10e of the lateral wall portion 10 in the vehicle width direction. The hole portion 50 of the bumper reinforcement 1 is deformed based on a collision load input in front of the hole portion 50, and the front wall surface 50sf thereof moves backward.

[0040] According to the above configuration, the hole 50 provided in the lateral wall portion 10 can absorb the collision load input from the front side of the vehicle to the end position 1e in the vehicle width direction during the deformation process of the hole 50. In particular, by retracting the front wall surface 50sf, it is possible to effectively suppress the direct transmission of the load F that is transmitted rearward by the bumper reinforcement 1 due to the input of the front collision load. This makes it possible to mitigate the front collision load transmitted rearward.

[0041] (2) The bumper reinforcement 1 includes, as its lateral wall portions 10, an upper wall portion 11 that connects the upper end portion 2a of the front wall portion 2 and the upper end portion 3a of the rear wall portion 3, and a lower wall portion 12 that connects the lower end portion 2b of the front wall portion 2 and the lower end portion 3b of the rear wall portion 3. The bumper reinforcement 1 also includes, as its lateral wall portions 10, an intermediate wall portion 13 that connects the front wall portion 2 and the rear wall portion 3 at a vertical position between the upper wall portion 11 and the lower wall portion 12. The bumper reinforcement 1 includes holes 50, 50 provided in the upper wall portion 11 and the lower wall portion 12, but does not have any holes 50 in the intermediate wall portion 13.

[0042] That is, by providing the side wall portion 10 without the hole 50 at the end position 10e in the vehicle width direction, when a front collision load is input, the hole 50 provided in each of the other side wall portions 10 deforms while the side wall portion 10 without the hole 50 undergoes buckling deformation. This makes it possible to suitably control the effect of mitigating the collision load transmission based on the deformation of the hole 50 provided in the side wall portion 10.

[0043] Furthermore, since the intermediate wall portion 13, which does not have the hole 50, is located between the upper wall portion 11 and the lower wall portion 12, which have the hole 50 at the end position 10e in the vehicle width direction, the hole portions 50 of the upper wall portion 11 and the lower wall portion 12 are deformed in a well-balanced manner. This makes it possible to more effectively mitigate the transmission of the collision load input from the front side of the vehicle to the end position 1e in the vehicle width direction.

[0044] (3) The hole 50 has an elongated hole shape extending in the vehicle width direction. That is, during an offset collision in which a collision load is input from the front side of the vehicle to the end position 1e of the bumper reinforcement 1 in the vehicle width direction, the input position of the collision load with respect to the end position 1e in the vehicle width direction is displaced relatively from the inside to the outside in the vehicle width direction. Therefore, when the hole 50 provided in the lateral wall portion 10 has an elongated hole shape extending in the vehicle width direction as described above, the input position of the collision load in front of the hole 50 moves relatively along the extension direction of the hole 50. This makes it possible to more effectively deform the hole 50 provided in the lateral wall portion 10 based on the front collision load input to the end position 1e in the vehicle width direction. As a result, the transmission of the front collision load can be more effectively mitigated. In addition, the effect of mitigating the collision load transmission can be controlled based on the length of the hole 50 extending in the vehicle width direction.

[0045] (4) The front wall surface 50sf of the hole 50, which has been retracted due to deformation, comes into contact with the rear wall surface 50sr of the hole 50. According to the above configuration, the front collision load absorbed by the deformation of the hole 50 accompanied by the retreat of the front wall surface 50sf is directly transmitted rearward by the contact between the front wall surface 50sf and the rear wall surface 50sr. This allows the timing at which the load F transmitted rearward increases to be controlled, thereby more suitably mitigating the transmission of the front collision load.

[0046] (5) The bumper reinforcement 1 includes a front cutout 30 formed by cutting out the front side of the vehicle at the end position 1e in the vehicle width direction, that is, the end positions 2e, 10e in the vehicle width direction of the front wall portion 2 and each of the lateral wall portions 10. The bumper reinforcement 1 includes a front plate 35 as a reinforcing member 40 fixed to the front cutout 30.

[0047] That is, since the front cutout 30 has a cross-sectional shape that opens toward the front side of the vehicle, which is the input direction of the collision load, each lateral wall portion 10 can be smoothly deformed at the end position 10e when the front collision load is input. This ensures smooth deformation of the hole 50 accompanied by the retreat of the front wall surface 50sf, thereby more suitably mitigating the front collision load transmitted to the rear.

[0048] (6) The bumper reinforcement 1 has the hole 50 in the lateral wall portion 10 behind the front plate 35. The bumper reinforcement 1 has the inner end portion 50eb in the vehicle width direction of the hole 50 at a position in the vehicle width direction substantially equal to the inner end portion 35eb in the vehicle width direction of the front plate 35.

[0049] According to the above configuration, the hole 50 located behind the front plate 35 can be smoothly deformed based on the front collision load input to the front plate 35. This makes it possible to more suitably mitigate the front collision load transmitted to the rear.

[0050] [Second embodiment] Hereinafter, a second embodiment of the bumper reinforcement will be described with reference to the drawings. For the sake of convenience, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

[0051] As shown in FIGS. 12 to 14, a bumper reinforcement 1B of this embodiment differs from the bumper reinforcement 1 of the first embodiment in the shape of holes 50B provided in the lateral wall portion 10B.

[0052] <Hole: Notched hole> More specifically, the hole 50B of this embodiment has a configuration as a notch hole 80 in which an outer end portion 50ea of ​​an elongated hole shape extending in the vehicle width direction opens to an end surface 10s of the lateral wall portion 10B in the vehicle width direction. Specifically, also in the bumper reinforcement 1B of this embodiment, the hole 50B is provided rearward of the front plate 35 fixed to the front cutout portion 30. Moreover, in the bumper reinforcement 1B of this embodiment, the hole 50B is disposed approximately parallel to the front wall portion 2. Thus, the hole 50B of this embodiment is configured so that the outer end portion 50ea of ​​the elongated hole shape extending in the vehicle width direction serves as an opening end 80e of the notch hole 80 and opens to the cutout end surface 10x of each lateral wall portion 10 that constitutes the front cutout portion 30 to which the front plate 35 is fixed.

[0053] In addition, apart from the above-mentioned differences regarding the shape and arrangement of the hole portions 50B as the cutout holes 80, the bumper reinforcement 1B of this embodiment also has substantially the same configuration as the bumper reinforcement 1B of the first embodiment in terms of the configuration of each hole portion 50B.

[0054] <effect> In the bumper reinforcement 1B of this embodiment, as in the first embodiment described above, the effect of mitigating the front collision load transmitted to the rear thereof is obtained during the process in which the hole portion 50B is deformed based on the collision load input in front of the hole portion 50B (see Figure 10).

[0055] That is, in the bumper reinforcement 1B of this embodiment, the hole 50B is also deformed based on a collision load input forward of the hole 50B, with the front wall surface 50sf thereof retreating. Furthermore, the front wall surface 50sf that retreats due to the deformation of the hole 50B comes into contact with the rear wall surface 50sr of the hole 50B. Furthermore, as the collision progresses, the contact area between the front wall surface 50sf and the rear wall surface 50sr of the deformed hole 50B gradually increases. As a result, the front wall surface 50sf and the rear wall surface 50sr of the hole 50B come into contact with each other in a state where they are in substantially full-area contact with each other.

[0056] <Test Results> 15 is a graph showing an example of test results relating to changes in load during a collision for the bumper reinforcement 1B of this embodiment. As shown by waveform M2 in the graph, the actual test results also confirm that the bumper reinforcement 1B of this embodiment has an effect of mitigating the front collision load transmitted to the rear.

[0057] Specifically, in the example shown in the waveform M2, when the value of the stroke X reaches "X7," the hole 50B begins to deform. Furthermore, when the value of the stroke X reaches "X8," the front wall surface 50sf of the deformed hole 50B comes into contact with the rear wall surface 50sr of the hole 50B. Furthermore, when the value of the stroke X reaches "X9," the front wall surface 50sf and the rear wall surface 50sr of the hole 50B come into contact with each other over substantially the entire surface. As a result, although the timing at which the load F transmitted rearward reaches its maximum value is delayed compared to the waveform M0 shown for reference, the front collision load transmitted rearward by the bumper reinforcement 1 is alleviated during the deformation of the hole 50B.

[0058] As described above, even when the configuration of this embodiment is adopted, it is possible to obtain the same effects as those of the first embodiment. Furthermore, since the hole 50B is the cutout hole 80 that opens in the end surface 10s of the lateral wall portion 10B, it is possible to easily manufacture the bumper reinforcement 1 having the hole 50 in the lateral wall portion 10 at the position that corresponds to the end position 1e in the vehicle width direction.

[0059] The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0060] In the above embodiments, the hole 50 provided in the lateral wall portion 10 is deformed by a front collision load, with the front wall surface 50sf thereof retreating. Furthermore, at this time, the retreated front wall surface 50sf abuts against the rear wall surface 50sr of the hole 50. After the front wall surface 50sf contacts the rear wall surface 50sr, the hole 50 further deforms, so that the front wall surface 50sf and the rear wall surface 50sr of the hole 50 come into contact with each other over substantially the entire surface. However, this does not necessarily mean that the front wall surface 50sf and the rear wall surface 50sr of the hole 50 come into contact with each other over substantially the entire surface. A portion of the hole 50 where the front wall surface 50sf and the rear wall surface 50sr do not come into contact with each other may remain. The recessed front wall surface 50sf does not necessarily have to come into contact with the rear wall surface 50sr of the hole 50.

[0061] In the above-described embodiments, the upper wall portion 11 and the lower wall portion 12 are provided with the holes 50, 50, and the intermediate wall portion 13 does not have the holes 50. However, this is not limited to this, and the number and positions of the lateral wall portions 10 having the holes 50 may be changed as desired. For example, the intermediate wall portion 13 may have the holes 50, and at least one of the upper wall portion 11 and the lower wall portion 12 may not have the holes 50. In other words, it is sufficient that at least one of the lateral wall portions 10 has the holes 50 at the end position 1e in the vehicle width direction.

[0062] The number of lateral wall portions 10 may also be changed as desired. That is, a configuration having four or more lateral wall portions 10 may be used. Furthermore, a configuration having only one lateral wall portion 10 is not excluded. The present invention may also be applied to a configuration having an intermediate vertical wall portion 15 that intersects with the lateral wall portion 10 along the front wall portion 2 and the rear wall portion 3 at a position between the front wall portion 2 and the rear wall portion 3 in the vehicle longitudinal direction.

[0063] In each of the above embodiments, the hole 50 has an elongated hole shape extending in the vehicle width direction. Furthermore, the front wall surface 50sf and the rear wall surface 50sr of the hole 50 are arranged substantially parallel to each other. The longitudinal end surface 50es of the hole 50 is a curved surface S that is continuous with the front wall surface 50sf and the rear wall surface 50sr.

[0064] However, the shape of the hole 50 is not limited to this and may be changed as desired. For example, the front wall surface 50sf and the rear wall surface 50sr do not necessarily have to be substantially parallel, and the distance between the front wall surface 50sf and the rear wall surface 50sr may increase or decrease from the inside to the outside in the vehicle width direction. Furthermore, the shape of the hole 50 does not necessarily have to be an elongated hole shape.

[0065] In each of the above embodiments, the bumper reinforcement 1 includes the front cutout 30 provided at the end position 1e in the vehicle width direction, and the front plate 35 as the reinforcing member 40 fixed to the front cutout 30. However, this is not limiting, and for example, a configuration in which a reinforcing member 40 having a shape different from that of the front plate 35 is fixed to the front cutout 30 may be used. Note that the method of fixing the reinforcing member 40 is also not necessarily limited to welding, and may be changed as desired, for example, by using an adhesive or a fastening member. Furthermore, a configuration in which the front cutout 30 is not provided at the end position 1e in the vehicle width direction may be used.

[0066] In the second embodiment, the hole 50B configured as the cutout hole 80 opens in the cutout end surface 10x of each lateral wall portion 10 that configures the front cutout portion 30. However, this is not limiting, and the opening position of the hole 50B may be changed as desired as long as it opens in the end surface 10s of the lateral wall portion 10B in the vehicle width direction.

[0067] The number and arrangement of the holes 50 provided at the end position 10e of the side wall portion 10 may be changed as desired. For example, in accordance with the elongated hole shape extending in the vehicle width direction as in each of the above embodiments, a plurality of holes 50 with small diameters may be arranged along the longitudinal direction.

[0068] In each of the above embodiments, the bumper reinforcement 1 is formed using an extruded material made of an aluminum alloy or the like. However, this is not limiting, and the material of the bumper reinforcement 1 and its manufacturing method may be changed as desired. Furthermore, the shape of the bumper reinforcement 1 does not necessarily have to be an arch-shaped curved shape in which the end positions 1e, 1e on both sides in the vehicle width direction are curved toward the rear of the vehicle.

[0069] <Additional Notes> Next, the technical ideas that can be understood from the above-described embodiments and modifications will be described. (i) The vehicle has a plurality of side wall portions arranged in the vertical direction, and at least one of the side wall portions has no hole at an end position in the vehicle width direction.

[0070] That is, by providing a side wall portion without a hole at the end position in the vehicle width direction, when a front collision load is input, the hole provided in the other side wall portion deforms while the side wall portion without a hole buckles, thereby making it possible to suitably control the effect of mitigating the front collision load transmission based on the deformation of the hole provided in the side wall portion.

[0071] (b) The hole extends in the vehicle width direction. That is, during an offset collision in which a collision load is input from the vehicle front side to an end position of the bumper reinforcement in the vehicle width direction, the input position of the collision load relative to the end position in the vehicle width direction displaces from the inside to the outside in the vehicle width direction. Therefore, when the hole provided in the side wall portion has an elongated hole shape extending in the vehicle width direction as described above, the input position of the collision load in front of the end position moves relatively along the extension direction of the hole. This makes it possible to more effectively deform the hole provided in the side wall portion based on the front collision load input to the end position in the vehicle width direction. As a result, the transmission of the front collision load can be more effectively mitigated. In addition, the effect of mitigating the collision load transmission can be controlled based on the length of the hole extending in the vehicle width direction.

[0072] (c) The hole opens to the end surface of the side wall in the vehicle width direction. According to the above configuration, it is possible to easily manufacture a bumper reinforcement having holes in the lateral wall portions at positions that correspond to the end positions in the vehicle width direction.

[0073] (d) The front wall surface that has retreated due to the deformation of the hole abuts against the rear wall surface of the hole. According to the above configuration, the front collision load absorbed by the deformation of the hole resulting from the recession of the front wall surface is directly transmitted rearward by contact between the front wall surface and the rear wall surface, thereby controlling the timing at which the load transmitted rearward increases, thereby more suitably mitigating the transmission of the front collision load.

[0074] (e) The lateral wall portion comprises an upper wall portion connecting the upper end of the front wall portion and the upper end of the rear wall portion, a lower wall portion connecting the lower end of the front wall portion and the lower end of the rear wall portion, and an intermediate wall portion connecting the front wall portion and the rear wall portion at a vertical position between the upper wall portion and the lower wall portion, and the upper wall portion and the lower wall portion have the hole portion at their end positions in the vehicle width direction, and the intermediate wall portion does not have the hole portion at their end positions in the vehicle width direction.

[0075] According to the above-described configuration, the intermediate wall without holes is positioned between the upper and lower wall portions having holes at their transverse end positions, which causes the holes in the upper and lower wall portions to deform in a balanced manner, thereby more effectively mitigating the transmission of a collision load input from the front of the vehicle to the transverse end positions.

[0076] (e) At the end positions of the front wall portion and the side wall portion in the vehicle width direction, there are provided front cutout portions cut out on the front side of the front wall portion and the side wall portion, and reinforcing members fixed to the front cutout portions.

[0077] That is, the front cutout has a cross-sectional shape that opens toward the front of the vehicle, which is the input direction of the collision load, so that when a front collision load is input, each side wall portion can smoothly deform at its end position. This ensures smooth deformation of the hole portion, which accompanies the recession of the front wall surface, and more effectively mitigates the front collision load transmitted to the rear.

[0078] (g) The hole is formed at the rear of the reinforcing member, and the inner end of the hole in the vehicle width direction is located at a position in the vehicle width direction substantially equal to the inner end of the reinforcing member in the vehicle width direction.

[0079] According to the above configuration, the hole located behind the reinforcing member can be smoothly deformed based on the front collision load input to the reinforcing member, thereby more preferably mitigating the front collision load transmitted to the rear.

[0080] (h) The front wall surface and rear wall surface of the hole are parallel to each other. (i) The longitudinal end faces of the hole are curved surfaces that are continuous with the front wall surface and the rear wall surface. [Explanation of symbols]

[0081] 1...bumper reinforcement, 2...front wall portion, 3...rear wall portion, 10...side wall portion, 10e...end position in the vehicle width direction, 50...hole portion, 50sf...front wall surface.

Claims

1. a front wall portion facing forward of the vehicle and extending in a vehicle width direction; a rear wall portion facing the rear of the vehicle and extending in a vehicle width direction; a lateral wall portion extending in a vehicle width direction and connecting the front wall portion and the rear wall portion; a hole provided at an end position of the side wall portion in the vehicle width direction, A bumper reinforcement in which the hole is deformed based on a collision load input in front of the hole, causing a front wall surface of the hole to retreat.

2. The vehicle has a plurality of side wall portions arranged in the vertical direction, and at least one of the side wall portions is not provided with the hole at an end position in the vehicle width direction. The bumper reinforcement according to claim 1 .

3. The hole extends in the vehicle width direction. The bumper reinforcement according to claim 1 or 2.

4. The hole opens to an end surface of the side wall in the vehicle width direction. The bumper reinforcement according to claim 1 or 2.

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