JP2005059766A - Bumper member for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bumper member for a vehicle exhibiting enhanced shock absorbing efficiency by restraining a stress peak value caused by a collision load. <P>SOLUTION: In this bumper member for the vehicle, a front plate 1 and a back plate 2 are arranged to confront to each other, and long side both end parts of the front plate and long side both end parts of the back plate are connected by two outer connecting plates 3. The front plate and the back plate are connected on an inner side between outer connecting plates by at least one of inner connecting plates 4, and protrusions protruding to the front side along an extended line of the outer connecting plate are arranged along the longitudinal direction of the front plate. In the bumper member, the collision load is first applied to the protrusion 6 on the front plate 1, the load is transmitted to the outer connecting plate 3 on the extended line of the protrusion 6, and the impact is primarily absorbed by buckling deformation of the outer connecting plate 3. Next, the outer connecting plate is deformed for the height of the protrusion, and thereby the collision load is transmitted from the front plate 1 to the other inner side connecting plate 3 having no protrusion 6, and the impact is secondarily absorbed by buckling deformation of the inner connecting plate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bumper member for a vehicle, and more particularly to a bumper member that is excellent in shock absorbing performance and suitable for use in a vehicle such as a truck.

  A bumper is attached to the vehicle for shock absorption. For example, FIG. 6 shows a bumper member 40 attached to the rear side of the truck 50 via a stay 51. As the bumper member, an aluminum alloy extruded material has recently been used for the purpose of reducing the weight of the vehicle. For example, the bumper member having a rectangular cross section shown in FIG. 7 is used. The vehicular bumper member 40 includes a front plate 1 and a back plate 2 which are arranged to face each other with a distance therebetween, and two long side ends of the front plate 1 and the back plate 2 are connected to each other outside. The front plate 1 and the back plate 2 are connected by a single inner connecting plate 4 at the center between the outer connecting plates 3 and 3. The bumper member 40 having the above shape is extruded with a cross-sectional shape as an extruded shape, and its longitudinal direction is the width direction, and is attached to the front or rear surface of the vehicle with the front plate 1 as the front side and the back plate 2 as the attachment side.

Further, in the rear bumper member, in many cases, a reflector 45 is attached to the front plate 1 as shown in FIG. In such a bumper member 41, in order to protect the reflection plate 45, there is also known one provided with overhang portions 3a and 3a projecting on the front side along the longitudinal direction at both ends of the long side of the front plate 1. (For example, Patent Document 1).
JP-A-9-95188 (FIGS. 1 and 2 etc.)

  By the way, in the conventional bumper member 40 shown in FIG. 7, a collision load when another vehicle collides is applied to the entire surface of the front plate 1 as shown in the figure, and this load is applied to the outer connecting plate 3 and the inner side. Since the bumper member 40 is transmitted to the connecting plate 4, the bumper member 40 exhibits a high bending strength, and a high stress is instantaneously generated in the bumper member 40. And when these three connection plates 3, 3, and 4 begin to buckle, a stress will show the characteristic which passes a peak and falls rapidly. Due to such a change in stress, the collision energy against the bumper member 40 is absorbed and the collision load is reduced. Moreover, in the bumper member 41 having the bulging portions 3a and 3a as shown in FIG. 8, when a collision load is applied, the load is applied to the three connecting plates 3, 3, and 4 via the bulging portions 3a and 3a. Therefore, a high stress is instantly generated in the same manner as the bumper member 40, and the stress rapidly decreases after a peak. In addition, it is considered that the stress peak value is slightly lower than that of the bumper member 40 due to plastic deformation of the bulging portions 3a and 3a at the time of collision, but the stress change exhibits almost the same form.

  As described above, conventional vehicle bumper members, including those having the overhanging portions, receive collision loads almost simultaneously on all connecting plates, so they are resistant to deformation, but the peak value of stress generated in the bumper members is high. It has the characteristic that it becomes high. Since this stress is transmitted to each part of the vehicle body and the passenger who receives the load, there is a problem that the impact of the collision is likely to be applied to the human body and the vehicle body and cause damage, which is not satisfactory in terms of shock absorption performance. It was.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle bumper member that has improved shock absorption performance by suppressing a stress peak value generated at the time of collision.

  In order to solve the above problems, the invention according to claim 1 of the vehicle bumper member of the present invention includes a front plate and a back plate that are arranged to face each other at a distance from each other, and both long side end portions of the front plate. Two outer connecting plates that respectively connect the long side side end portions of the back plate, and one or more inner connecting plates that connect the front plate and the back plate inside the outer connecting plate. The front plate is provided with a ridge protruding along the longitudinal direction of the front plate on the extension line of the outer connecting plate.

  The invention for the vehicle bumper member according to claim 2 is the invention according to claim 1, wherein the inner wall surface of the ridge is located at substantially the same position as the inner wall surface of the outer connecting plate or inside thereof. It is characterized by that.

  The invention of the vehicle bumper member according to claim 3 is characterized in that, in the invention of claim 1 or 2, a fillet portion is provided on the inner surface side of the connecting portion between the front plate and the outer connecting plate. To do.

  The invention of the bumper member for a vehicle according to claim 4 includes a front plate and a back plate which are arranged to face each other at a distance from each other, both long side ends of the front plate and both long side ends of the back plate. Two outer connecting plates that connect each other, and one or more inner connecting plates that connect the front plate and the back plate inside the outer connecting plate, A ridge protruding to the front side on an extension line of the inner connecting plate is provided along the longitudinal direction of the front plate.

  That is, according to the present invention, when a collision load is applied, the collision load is first applied to the ridge formed on the front plate of the bumper member, and the load is transmitted to the outer connecting plate continuous with the ridge. When the outer connecting plate is buckled and deformed, the impact is primarily absorbed, and then the outer connecting plate is deformed and buckled and the impact is directly applied to the front plate. Load is transmitted to the connecting plate. The other connecting plate continues to buckle and further absorbs the impact. By absorbing the impact stepwise in this way, the peak value of the collision load can be kept low, and the impact is effectively absorbed by the deformation of each connecting plate.

  The inner wall surface of the ridge is added to the ridge by being positioned substantially at the same position as the inner wall surface of the outer connecting plate or on the inner side (in the bumper member) as in the invention described in claim 2. Load can be smoothly transmitted to the outer connecting plate. When this inner wall surface is located on the inner side greatly beyond the inner wall surface of the outer connecting plate, the collision load applied to the protrusion is not directly applied to the outer connecting plate, but is transmitted to the inner outer side of the protrusion through the front plate. Therefore, the load is transmitted almost simultaneously not only to the outer connecting plate but also to the inner connecting plate, the above-mentioned stepwise shock absorption cannot be performed, and the peak value of the stress at the time of collision becomes high, so the object of the present invention cannot be achieved. Accordingly, assuming that the position of the outer wall surface of the ridge coincides with the outer wall surface of the outer connecting plate, the thickness of the ridge is preferably not more than three times, more preferably not more than twice the thickness of the outer connecting plate. Is preferred. Also, if the thickness of the ridge is particularly small compared to the thickness of the outer connecting plate, the ridge will buckle before the outer connecting plate buckles when a collision load is applied. Is not particularly thinner than the outer connecting plate, and is preferably substantially the same as or thicker than the outer connecting plate. From the above points, it is further desirable that the inner wall surface of the ridge is located at the same position as the inner wall surface of the outer connecting plate or at an inner side close to this position. In the present invention, the thickness of the protrusions and the thickness of the outer connecting plate may be based on the positions where they are connected to the front plate.

Further, as described in claim 3, when the fillet portion is provided on the inner surface side of the connection portion between the front plate and the outer connection plate, the inner wall surface of the ridge is formed of the fillet portion. What is necessary is just to be located in the substantially same position as an inner side edge, or the outer side from this inner side edge. If this has a fillet part, even if the inner wall surface of the ridge extends beyond the inner wall surface of the outer connecting plate, it is almost the same position as the inner edge of the fillet part or the inner edge. Since the load applied to the ridge by being positioned outside the edge is smoothly transmitted to the outer connecting plate through the fillet portion and the transmission of the load to the inner connecting plate is suppressed, the above-described effect of the present invention can be obtained. . Further, it is desirable that the inner wall surface of the ridge is located at the same position as the inner edge of the fillet part or at the outer side close to this. When the inner edge of the fillet portion does not reach the position twice or three times the thickness of the outer connecting plate, the inner wall surface of the ridge extends beyond the inner edge of the fillet portion. In that case, as shown above, the inner wall surface of the ridge is preferably a position not more than three times the thickness of the outer connecting plate, and more preferably not more than twice the position. Indicated. In addition, when the inner edge of the fillet part exceeds the position twice or three times the thickness of the outer connecting plate, the inner wall surface of the ridge is substantially the same position as the inner edge of the fillet part, or What is necessary is just to be located outside the inner edge, but it is preferable that the inner wall surface of the ridge is located at a position not more than 3 times the thickness of the outer connecting plate, and not more than 2 times. The position is more preferred. Further, like the above, it is not preferable that the thickness of the protrusions is particularly thin as compared with the thickness of the outer connecting plate, and it is preferable that the thickness of the protrusion is substantially the same as or thicker than that of the outer connecting plate.
In the present invention, the inner wall surface position of the ridge may be based on the position where the ridge is connected to the front plate.
Moreover, although the height of the said protrusion can be selected suitably, the height of 1-4 mm can be illustrated as a suitable thing, and 2-4 mm is shown as a more suitable thing.

  Furthermore, the above-mentioned ridges may be provided on the extension of the outer connecting plate, or instead, the ridges may be provided on the extension of the inner connecting plate as described in claim 4. In this configuration, the load is transmitted to the inner connecting plate through the protrusions at the initial stage of the collision, and then the load is applied to the front plate and the outer connecting plate along with the buckling of the inner connecting plate, and stepwise shock absorption is performed. The In this embodiment, the inner and outer wall surfaces of the ridge are located at substantially the same position (preferably the same position) as the inner and outer wall surfaces of the inner connecting plate, or on the outer side with respect to the inner connecting plate center side (thickness direction). Is desirable. Also in this case, the thickness of the protrusion is preferably 3 times or less, more preferably 2 times or less the thickness of the inner connecting plate. In addition, when the fillet portion is provided in the connecting portion between the front plate and the inner connecting plate, the inner and outer wall surfaces of the ridge are substantially the same position (preferably the same position) as the side edge of the fillet portion. It is desirable to be located on the inner connecting plate center side (thickness direction).

In addition, in the present invention, in addition to the protrusions described above, there are protrusions for attaching the reflecting plate on the surface side of the front plate as long as the load transmission function of the present invention described above is not impaired. You may do it.
In the present invention, the bumper member can usually be constituted by an extruded material. However, the present invention is not limited to this, and each plate or protrusion is formed or welded by other methods. It may be a thing. Further, a combination of extrusion and other processing may be used.

  As described above, according to the vehicle bumper of the present invention, it is possible to absorb a collision load step by step due to the presence of a protrusion that regulates an appropriate position and wall surface position, and the peak value of the stress at the time of collision is reduced. It is possible to suppress the impact applied to the human body and the vehicle body and prevent the occurrence of damage.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a front view showing a vehicle bumper member 10 according to an embodiment of the present invention, and FIG. 2 is a right side view thereof.

  In this embodiment, an aluminum alloy extruded material is used as a bumper member for a vehicle, and JIS standard 5000 series, 6000 series, 7000 series aluminum alloys, etc. are mainly used as the material. In the present invention, the material of the vehicle bumper member is not particularly limited to the above, and other materials may be used as necessary.

  As shown in FIGS. 1 and 2, the vehicle bumper member of the present invention has a long front plate 1 and a back plate 2 that face each other with a distance therebetween, and the long side of the front plate 1. Two outer connecting plates 3 and 3 that connect the two side ends and the long side side end of the back plate 2 are provided so as to face each other. Furthermore, the front plate 1 and the back plate 2 are connected by two inner connecting plates 4 and 4 inside the outer connecting plates 3 and 3, and the inner connecting plates 4 and 4 are connected to the outer connecting plate 3 and 4. It is inclined at a small angle with respect to 3, and is arranged in an inverted C shape (shown in FIG. 2). In addition, about the inclination angle of the inner side connection plates 4 and 4, arbitrary angles including the case where it makes it parallel to the outer side connection plates 3 and 3 can be selected suitably. In this embodiment, the inner connecting plate 4 is composed of two sheets. However, the present invention does not limit the number of sheets, and one sheet or a plurality of sheets are appropriately selected. An attachment portion 5 for attaching a bumper member to the stay of the track is provided between the inner side of the back plate 2 and the inner connecting plate 4.

  Further, at both ends of the long side of the front plate 1, protrusions 6 having a thickness B that is substantially the same as the thickness t of the outer connecting plate 3 are provided at a height H on the extension line of the outer connecting plates 3 and 3. The protrusion 6 extends along the longitudinal direction of the front plate 1. The vehicle bumper member 10 having these structures can be obtained by extrusion and finishing as necessary.

Next, the operation of the vehicle bumper member 10 will be described.
When a collision load is applied to the vehicle bumper member 10 from the front side, at the time of the collision, the collision load is first applied to the ridges 6 and 6 on both ends of the long side of the bumper member 10, and further the extension of the ridges 6 and 6. It is transmitted to the outer connecting plates 3 and 3 on the line. At the beginning of the collision, a load is received by the pulling action of the outer connecting plates 3, 3, and buckling deformation of the ridges 6, 6 and the outer connecting plates 3, 3 starts. The stress generated in the bumper member 10 is saturated until the buckling for the height of the protrusions 6 and 6 progresses in the outer connecting plates 3 and 3. As the protrusions 6 and 6 are further deformed by the height, the load is applied to the front plate 1 from the protrusions 6 and the outer connecting plates 3 and 3, and is transmitted to the inner connecting plates 4 and 4, and the stress gradually increases. To do. Immediately before the inner connecting plates 4 and 4 start to buckle, the stress shows a peak value, and the stress gradually decreases as the inner connecting plates 4 and 4 buckle. By these deformations, the maximum stress (peak) value is kept lower than that of the conventional bumper member, and appropriate stress continues to be maintained as the displacement increases, and excellent shock absorption characteristics are exhibited.

Next, FIG. 3 is a side view showing a vehicle bumper member 20 according to another embodiment. In addition, about the structure similar to the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted or simplified.
The vehicle bumper member 20 of this embodiment includes a front plate 1, a back plate 2, and two outer connecting plates 3, 3 that connect both side edges of the front plate 1 and the back plate 2, respectively, Two inner connection plates 4, 4 that connect the front plate 1 and the rear plate 2 inside the outer connection plates 3, 3 are provided.

Furthermore, the vehicle bumper member 20 of this embodiment is provided with fillet portions 21 and 21 on the inner surface side of the connecting portion between the front plate 1 and the outer connecting plates 3 and 3, respectively. At both side edges, ridges 22 are formed on the extended lines of the outer connecting plates 3 and 3 so that the inner wall surface is located at substantially the same position as the inner edges 21a and 21a of the fillet portions 21 and 21. The protrusions 22 and 22 extend along the longitudinal direction of the front plate 1.
In this embodiment, the inner rib 4 is composed of two sheets. However, the number of the inner ribs 4 is not limited as in the above example.

  Also in the vehicle bumper 20 of this embodiment, the collision load at the time of collision is first applied to the ridges 22, 22 on the both ends of the long side, and this load is applied to the outer connecting plate 3 via the fillet portions 21, 21. 3, the outer connecting plates 3, 3 exhibit a pulling action, and the stress generated in the bumper member 20 increases. When the outer connecting plates 3 and 3 start to buckle and deform, the stress becomes saturated. When the outer connecting plates 3, 3 are deformed by the height of the ridges 22, 22, the load is applied to the front plate 1 from the ridges 22, 22 and the outer connecting plates 3, 3 and is transmitted to the inner connecting plates 4, 4. The stress increases gradually. The stress shows a peak value immediately before the inner connecting plates 4 and 4 start to buckle, and the stress gradually decreases as the inner connecting plates 4 and 4 buckle. By these deformations, the effect of reducing the maximum stress value and improving the impact absorbing performance can be obtained as in the above embodiment.

  In each of the above-described embodiments, the inner wall surface of the ridge 6 is located at substantially the same position as the inner wall surface of the outer connecting plate, and the inner wall surface of the ridge 22 is located at substantially the same position as the edge 21 a of the fillet portion 21. However, the protrusion 6 may be located on the inner side (direction in the bumper member), and the protrusion 22 may be located on the outer side.

FIG. 4 is a side view showing a bumper member 30 of still another embodiment. Also in this embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In the bumper member 30 of this embodiment, the protrusions 31 and 31 are provided on the extension of the inner connection plates 4 and 4, and the protrusions 31 and 31 are formed with the same thickness as the inner connection plates 4 and 4. Has been. In this embodiment, the collision load is first transmitted from the ridges 31, 31 to the inner connecting plates 4, 4, and is saturated until the inner connecting plates 4, 4 are buckled and deformed by the height of the ridges 31, 31. After that, the load is transmitted to the outer connecting members 3 and 3 to show the peak value of the stress, and then the stress gradually decreases with the buckling of the outer connecting members 3 and 3. In this embodiment, the effect of reducing the maximum stress value and improving the impact absorbing performance can be obtained as in the above embodiments.
In this embodiment, the protrusion 31 has been described as having the same thickness as the inner connecting plate 4, but the thickness of the protrusion can be made thicker than the inner connecting plate 4. When the fillet portion is provided between the plates 4 and 4 and the front plate 1, the wall surface of the ridge may be located up to the edge of the fillet portion.

  Next, examples of the present invention will be described. A bumper member 10 having the shape shown in the first embodiment was prepared by an extruded material using a JIS standard A6N01SS-T5 material. The bumper member 10 has a shape with a height of 75 mm and a depth of 500 mm with the front plate 1 facing upward, and the front plate 1, the back plate 2, the outer connecting plates 3 and 3, and the inner connecting plates 4 and 4. The thickness of the protrusions 6 and 6 was 3 mm. Five types of ridges 6 with different heights (1, 2, 3, 4 mm) and those without ridges 6 are prepared, and a load is applied to these with a load jig of 200 mm width (longitudinal direction). The stress-displacement curve in each bumper member was examined. FIG. 5 is a graph showing the results, with the vertical axis representing stress and the horizontal axis representing displacement.

As is clear from FIG. 5, in the case of a bumper member having no protrusion (corresponding to a conventional material), a high stress peak value appears because the outer connecting plate on both ends and the two inner connecting plates are simultaneously loaded. After the peak, the stress decreases rapidly.
On the other hand, when the height of the ridge is 1 mm, the inner connecting plate receives a load before the outer connecting plates at both ends are buckled and deformed (within the elastic deformation range). At the end, as in the case of the flat surface, a high peak value appears, and the stress decreases after reaching the peak. However, the extent of the decline is not as rapid as those without ridges. In this bumper member, the outer connecting plates at both ends are plastically deformed to some extent, so that the peak value is not as high as that without the protrusions, and the effect of the protrusions appears to some extent.

  Also, when the height of the ridge is 2 to 4 mm, the load is peaked once at 100 to 150 kN due to buckling deformation of the outer connecting plates at both ends, and is almost constant until the deformation of the ridge is finished. The load (saturation) is maintained. When the buckling deformation of the outer connecting plate further proceeds, the load jig comes into contact with the front plate 1, the inner connecting plate receives a load, and the stress increases again to reach the second stress peak, and then the stress value gradually increases. To drop. From this test result, it can be seen that the peak value of the second time becomes lower as the height of the ridge is larger, and the tendency of the stress to decrease with increasing displacement becomes smaller.

From the above result, the stress-displacement curve can be changed by adjusting the height of the protrusion. For example, when emphasizing the peak value, the height of the ridge is lowered, and if it is important to maintain a constant stress such as energy absorption, the height of the ridge may be increased.
In this example, the peak value of the stress could be kept low by setting the height of the protrusions to 3 and 4 mm, and good shock absorbing performance as a bumper member could be obtained. In addition, a present Example shows an example and the height of a protrusion is not limited to 3-4 mm. That is, a desired stress-displacement curve can be obtained depending on required specifications, material, thickness of outer connecting plate, thickness / number of inner connecting plates, mounting angle, dimensions, height of protrusion, and the like.

It is a front view which shows one Embodiment of the bumper member for vehicles of this invention. It is a side view showing one embodiment similarly. It is a side view which similarly shows other embodiment. It is a side view which shows other embodiment similarly. It is a graph which similarly shows the stress-displacement curve in each bumper member from which the height of a protrusion differs. It is a perspective view which shows an example of the use condition of the bumper member for vehicles. It is a perspective view which shows the conventional bumper member for vehicles. It is a perspective view which shows the other conventional bumper member for vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Outer connection plate 4 Inner connection plate 5 Mounting part 6 Projection 10, 20, 30, 40, 41 Vehicle bumper 21 Fillet part 22 Projection 31 Projection 50 Track 51 Stay

Claims (4)

A front plate and a back plate that are arranged to face each other at a distance from each other; two outer connecting plates that respectively connect the long-side-side side ends of the front-side plate and the long-side-side side ends of the back plate; One or a plurality of inner connecting plates that connect the front plate and the rear plate on the inner side between the outer connecting plates are provided, and the front plate projects to the front side on the extension line of the outer connecting plate. A bumper member for a vehicle, wherein a protrusion is provided along a longitudinal direction of the front plate. 2. The vehicle bumper member according to claim 1, wherein an inner wall surface of the ridge is located at substantially the same position as or on the inner side of the inner wall surface of the outer connecting plate. The vehicle bumper member according to claim 1, wherein a fillet portion is provided on an inner surface side of the connecting portion between the front plate and the outer connecting plate. A front plate and a back plate that are arranged to face each other at a distance from each other; two outer connecting plates that respectively connect the long-side-side side ends of the front-side plate and the long-side-side side ends of the back plate; One or a plurality of inner connecting plates that connect the front plate and the rear plate on the inner side between the outer connecting plates are provided, and the front plate projects to the front side on an extension line of the inner connecting plate. A bumper member for a vehicle, wherein a protrusion is provided along a longitudinal direction of the front plate.

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