JP5106073B2 - Automotive bumper reinforcement - Google Patents

Description

  The present invention relates to a structure of a bumper reinforcing material made of an aluminum alloy extruded profile attached to the front and rear of an automobile.

Inside the bumper attached to the front end (front) and rear end (rear) of the body of the automobile, a bumper reinforcing material (also called bumper reinforcement or bumper armature) is provided as a strength reinforcing material.
As is well known, the bumper reinforcing member is disposed between the bumper and the vehicle body so as to extend in a substantially horizontal direction with respect to the vehicle body and in parallel with the vehicle width direction. And it is common to curve partially or entirely according to the design curvature in a vehicle plan view.

With regard to such bumper reinforcements, the desire to further reduce the weight of the vehicle body has become stronger in response to the global environment, and instead of the steel materials used in the past, extruded hollow shapes made of high-strength aluminum alloys and Ultra high strength steel sheets are starting to be used.
In particular, aluminum alloy extruded profiles can form a closed section structure without joining such as welding, and can change the thickness distribution in the section. Have. A general aluminum extruded shape bumper reinforcing material has a uniform cross section in the longitudinal direction of extrusion and is often used after being partially or wholly bent according to the design curvature.
These bumper reinforcing members are attached to the vehicle body by being connected to vehicle body frames (vehicle body members) of skeleton members in the vehicle longitudinal direction such as front side members and rear side members. Further, the bumper reinforcing member is fixed to the vehicle body directly on the front or rear end of the front and rear side members of the vehicle body or via a support member (vehicle body connection member) from the rear surface such as a bumper stay.

As is well known, the bumper reinforcing member constitutes an energy absorbing member for a vehicle body against a collision from the front or the rear of the vehicle body or a collision from the front or the rear between the bumper and the vehicle body. Therefore, the bumper reinforcement as an energy absorbing member for the vehicle body is subjected to the collision energy applied from the front of the bumper reinforcement material due to the collision of the vehicle body, and its own bending deformation and crushing deformation in the vehicle longitudinal direction (substantially horizontal cross-sectional direction). The ability to absorb and protect the vehicle body by (crush) is required.
When the bumper reinforcement member receives a collision force, the bumper reinforcement member usually undergoes bending deformation in which a portion closer to the center than the stay mounting portion is bent backward due to bending deformation. When this deflection deformation becomes large, the deformed bumper reinforcing material approaches the vehicle body side, interferes with various automobile parts such as a radiator located behind the bumper, and is likely to be damaged.

  On the other hand, conventionally, measures have been taken to increase the bending strength of the bumper reinforcing material in order to increase the impact energy absorbability of the bumper reinforcing material and prevent interference and damage to various rear automobile parts. In order to improve the bending strength of the bumper, it is necessary to increase the strength of the material or increase the section modulus of the bumper reinforcement. In order to increase the section modulus while minimizing the increase in weight, it is advantageous to increase the width of the bumper reinforcement in the longitudinal direction of the vehicle body, and in the longitudinal direction of the vehicle body within a range where interference with other parts can be avoided. The width is often increased.

On the other hand, the required length of the side member to which the bumper reinforcement is connected is generally determined from the viewpoint of securing the amount of energy absorption in high-speed collisions, and the joint position of the bumper reinforcement with the vehicle body is defined accordingly. . On the contrary, since the collision surface side is defined according to the vehicle design, the bumper reinforcing material needs to be arranged in the space defined at the joint position between the vehicle design and the side member. In particular, in the event of a collision from the front of the vehicle body, it is also necessary to provide energy absorbing parts for the purpose of protecting the pedestrian's legs on the front surface of the bumper reinforcing material. There is a tendency to become very narrow at the outer portion in the width direction, that is, at the end in the vehicle width direction.
In other words, the bumper reinforcing material is required to satisfy the conflicting demands of increasing the cross-sectional width in the vehicle front-rear direction and saving space at the end in the vehicle width direction in order to improve bending strength.

  The amount of deformation is greatest at the time of a collision when a collision load is applied in the vicinity of the center of the bumper reinforcement having the longest distance from the support point. At this time, the bending moment is highest in the central portion of the bumper reinforcement. In order to cope with this, several structures have been proposed to increase the section modulus near the center in the longitudinal direction compared to the mounting part of the bumper reinforcement, and to cope with the above-mentioned mounting space constraints and to improve the bending strength. Has been.

For example, in the case of a bumper reinforcement made of a hat-formed or roll-formed product such as a steel plate, the cross-sectional shape can be changed relatively easily in the longitudinal direction. For example, structures such as Patent Documents 1 and 2 have been proposed for hat-shaped products having an open cross section.
In addition, these open cross-section structure bumper reinforcements are more likely to open and deform in cross-section than a bumper reinforcement with a closed cross-section structure, and the deformation load decreases rapidly after reaching the maximum load, resulting in poor energy absorption performance. There's a problem.

Moreover, the structure like patent document 3, 4 is proposed also about the case where the structure which comprised the closed cross-section structure with the board components.
These are bumper reinforcements composed of two or more parts, and there is a problem of cost increase due to an increase in the number of parts. Moreover, since it becomes a problem, such as the strength fall resulting from welding, the bumper reinforcement material structure by one part is desired.

On the other hand, several bumper reinforcing material structures having a single-component configuration and a different cross section in the longitudinal direction have been studied and put into practical use by performing press working on a part in the longitudinal direction. Examples of the case where the end portion of the bumper reinforcing material is press-molded substantially in the vehicle front-rear direction include structures as described in Patent Documents 5 and 6. In addition, as an example of press crushing a collision surface side end portion of a shape member having no joint portion such as an aluminum alloy extruded shape, a structure as in Patent Document 8 has been proposed.
However, Patent Document 8 and Patent Document 5 are obtained by reducing the width in the vehicle front-rear direction on the side of the shape member by simply deforming the web and the middle rib into a U-shape.
In such a structure, the middle rib and the web are deformed in advance in a square shape. For this reason, when a collision with the crushing deformation part occurs, there is a problem that the cross section itself is easily deformed. That is, there is a problem that the crushing process on the end side is inferior in the collision characteristics with respect to the collision from the vehicle body end side. In the structure of Patent Document 6, the bumper that needs to have the highest bending strength is required. The central portion of the reinforcing material has a substantially rectangular cross section without a middle rib. For this reason, there is a problem that buckling deformation is likely to occur on the flange surface and the characteristics in the center collision are inferior.

  On the other hand, the bumper reinforcing member is generally joined to a vehicle body or a stay at the end thereof. For this reason, when a crushing process is performed on the end portion, it is often a problem to secure the joint surface. For example, the structures shown in Patent Documents 5 and 6 described above are structures in which the back side (vehicle body side) of the bumper reinforcing material is crushed. Thus, when crushing the back side (vehicle body side), there is a problem that it is difficult to ensure the shape accuracy of the joint surface because the back side is deformed during crushing.

In order to ensure the accuracy of the joint surface, it is common to constrain deformation of this portion using a tool. However, in the end crushing process as described above, even if a tool is inserted from the end side that is the opening, it is difficult to restrain the necessary part, and it is difficult to suppress the deformation of this part. I can say that.
Thus, as in Patent Document 7, a method of securing shape accuracy by hydroforming after press working has been proposed, but there is a problem that the manufacturing cost is significantly increased. In particular, in the hydroform of an extruded shape member having a middle rib, there is often a problem that the middle rib itself is deformed unless the pressure balance is controlled well.

Moreover, since the above-mentioned patent document 8 crushes the collision surface side, the deformation of the back side flange serving as the joint surface is reduced. However, Patent Document 8 and Patent Document 5 are obtained by reducing the width in the vehicle front-rear direction on the side of the shape member by simply deforming the web and the middle rib into a U-shape.
When the bumper reinforcing material is bolted to the vehicle body or the stay, the web or the middle rib protruding inside the cross section becomes an obstacle and often cannot secure the necessary bolt space. Such a bumper reinforcing material can be applied only when the flange surface is wide enough to secure an area necessary for bolt connection even when a U-shaped deformation of the web or the intermediate rib occurs. However, when the vertical width of the flange is increased, buckling is likely to occur, resulting in a problem that the collision performance is reduced. In other words, it can be said that the bumper reinforcing material having such a structure is substantially difficult to be fastened to the vehicle body by a bolt and needs to be joined to the vehicle body via a welded joint with the stay.

Conversely, the shape of the bumper mounting part is used as the reference cross section, and the center part is crushed in the vertical direction of the vehicle body to increase the section modulus near the center of the cross-sectional bumper, ensuring both space at the vehicle body mounting part and bending strength at the center part The structures shown are also proposed in Patent Documents 9 and 10.
These structures are formed by pressing from the vertical direction of the vehicle body and projecting the central portion toward the vehicle body side. However, such processing can achieve a predetermined effect when the target cross-sectional shape is a mouth mold without a medium rib, but when applied to a cross-sectional shape provided with a medium rib, the medium rib is a flange. Therefore, it is difficult to increase the overhang amount, and there is a disadvantage that the effect is reduced.

JP-T-2006-527122 JP 2005-500196 Gazette JP-A-7-2033 JP 2007-45171 A JP 2003-146156 A Special table 2003-516902 gazette JP 2003-146159 A Japanese Patent Laid-Open No. 7-25296 JP 2001-63495 A US Pat. No. 6,343,820

In recent years, bumper reinforcements for automobiles have been increasing in size in order to respond to stricter collision safety standards and collisions with other vehicles with different vehicle heights. From the standpoints of ensuring shape accuracy in processing (suppressing wrinkles and dents) and ensuring shape accuracy during extrusion, it is essential to provide an intermediate rib in the cross section.
The present invention has been made in view of the above situation, and in a bumper reinforcement made of extruded aluminum alloy having a closed cross-sectional structure provided with an intermediate rib, both end portions in the vehicle width direction by press working capable of mass production. To secure the bending strength of the bumper reinforcement and to reduce the mounting space to the vehicle body at the end in the vehicle width direction by increasing the section modulus at the center in the vehicle width direction compared to the section modulus at the end. The main purpose is to improve the collision characteristics of the crushed end portion in the vehicle width direction. Another object of the present invention is to stably obtain the crushed shape by the press.

The bumper reinforcement according to the present invention includes a flange on the vehicle body side and a collision side that are spaced apart in the front-rear direction of the vehicle body, and an upper and lower web that is spaced apart in the vertical direction of the vehicle body and connects the flanges. At least one middle rib located between the upper and lower webs and having a length in the front-rear direction shorter than the distance between the front and rear directions of the two flanges, and connected to the vehicle body side and / or the collision side end of each middle rib together with the middle rib It is composed of upper and lower oblique walls having a cross-sectional groove shape connecting both flanges, and each of the upper and lower oblique walls has one or more fold points that are recessed in the cross-section inward direction at an intermediate position. It is made of an aluminum alloy extruded shape with its closed end connected to the end of the middle rib and the open end connected to the vehicle body side or the flange on the collision side. Crushed toward the side Together they are processed, and wherein the cross-sectional height of the crush processed portion is greater than the medium equal to or longitudinal length of the rib. The groove shape formed by a pair of upper and lower oblique walls typically a substantially V-shaped, the inclined wall is composed of planar walls, respectively.
As for the said bumper reinforcement material , it is desirable for a web to have two or more fold points in the intermediate position, respectively.

According to the present invention, an aluminum alloy extruded shape member having one or more medium ribs inside a closed cross section is used as a bumper reinforcing material that is lightweight and has excellent impact characteristics, and both ends in the vehicle width direction are crushed by pressing. By improving the bending strength of the bumper reinforcing material by increasing the section modulus of the bumper-reinforcing material in the center portion in the vehicle width direction compared to the section modulus in the end portion in the vehicle width direction, the end portion in the vehicle width direction The space can be reduced at the same time.
Then, the length of the middle rib in the front-rear direction is made shorter than the distance between the front and rear directions of both flanges, and the cross-sectional height of both ends in the vehicle width direction after crushing is set equal to or larger than the length of the middle rib in the front-rear direction. Therefore, when the both ends in the vehicle width direction are crushed, the inclined wall having a substantially V-shaped cross section is bent or deformed at the portion, while the U-shaped deformation of the middle rib is suppressed. Collision characteristics (energy absorption performance) can be improved by suppressing cross-sectional deformation at the end in the vehicle width direction (crushed portion).

Further, by an intermediate position of the upper and lower inclined wall to form one or more break points is concave in cross-section inwardly, also when forming a two or more break points in the web of the intermediate position, the swash during crushing processing When the wall is bent and deformed starting from the break point, the crushing process by the press is stably performed. Further, when the above-mentioned fold points are formed on the upper and lower inclined walls, the flange connected to the inclined wall is less likely to be displaced in the vertical direction, and even when the crushed portion is used as a bolt mounting portion with the vehicle body or stay, Positional displacement between the bolt hole formed on the side flange and the work hole formed on the collision side can be prevented and bolt joining is facilitated. On the other hand, if two or more break points are formed at the intermediate position of the web, However, the amount of overhang of the web in the vertical direction of the vehicle body is suppressed, and the shape accuracy of the flange is improved.

Hereinafter, with reference to FIGS. 1-12, the bumper reinforcement which concerns on this invention is demonstrated concretely.
The bumper reinforcing material according to the present invention is made of an integral aluminum alloy extruded shape, and is initially straight and has substantially the same cross-sectional shape in the longitudinal direction, as shown in FIG. And is crushed so that the thickness in the front-rear direction becomes smaller toward the ends at both ends in the vehicle width direction. The bumper reinforcing material is fixed to the tip of the stay 1 with a bolt at the end where the crushing process has been performed.
As can be seen from the phantom line B (the shape before the crushing process) shown in FIG. 1, there is no movement of the material at the end of the crushing process compared to the part where the crushing process is not performed, and the collision occurs. Material movement occurs only on the side. In other words, the crushing end portion is press crushing toward the vehicle body side.
FIG. 2 is an example of a cross-sectional shape of the bumper reinforcing material, and a cross-section C indicated by a solid line is a cross-sectional shape of a C-C cross-section (see FIG. 1) in a central portion where crushing is not performed, and a cross-section A indicated by an imaginary line Is the shape of the AA end face (see FIG. 1) of the end portion subjected to the crushing process.

  The bumper reinforcing material (cross section C) shown in FIG. 2 has a vehicle body side flange 2 and a collision side flange 3 that are positioned at a predetermined interval in the longitudinal direction of the vehicle body, and both flanges that are positioned at a predetermined interval in the vertical direction of the vehicle body. 2 and 3, the upper and lower webs 4 and 5, the middle rib 6 located at the center of both webs 4 and 5, and the upper and lower diagonals forming a substantially V-shaped cross section connecting the flanges 2 and 3 together with the middle rib 6 It consists of walls (upper inclined wall 7 and lower inclined wall 8), and these constitute two closed sectional structures. Both flanges 2 and 3 are disposed in a substantially vertical plane, and both webs 4 and 5 and the middle rib 6 are disposed in a substantially horizontal plane. The end of the intermediate rib 6 on the vehicle body side (the end close to the vehicle body side flange 2) is joined to the vehicle body side flange 2, and the collision side end of the intermediate rib 6 closes the upper and lower inclined walls 7 and 8 having a substantially V-shaped cross section. The ends on the opening side of the upper and lower inclined walls 7, 8 are connected to the collision side flange 3. The collision side flange 3 is not located between both ends of the inclined walls 7 and 8 and is divided into two, an upper collision side flange 3a and a lower collision side flange 3b.

  The slant walls 7 and 8 are respectively composed of flat wall surfaces 7a, 7b, 8a and 8b, and one folding point 9 which is concave in the inner side of the cross section is provided at an intermediate position (folding depth S). Further, the webs 4 and 5 are provided with four folding points 10 at intermediate positions, the surfaces 4a, 5a, 4b and 5b connected to the flanges 2 and 3, the web center surfaces 4c and 5c, and 2 connecting each of these. The four surfaces 4d, 5d, 4e, and 5e are composed of a total of five flat wall surfaces, the wall surfaces 4a to 4c and 5a to 5c are substantially horizontal, and the web center surfaces 4c and 5c project outward from the cross section.

  On the other hand, when the cross section A (A-A end face of the end portion) of the end portion subjected to press crushing is viewed, the slant walls 7 and 8 are bent and deformed from the break point 9 and the webs 4 and 5 are Bending deformation (inclined wall surfaces 4d, 5d, 4e, and 5e collapsed) as a starting point, the center portion protrudes to the outside of the cross section, the collision side flange 3 moves to the vehicle body side, and the cross section height of the bumper reinforcement (front and rear) (Thickness in the direction) is small. Moreover, this crushing process is such that the cross-sectional height of the bumper reinforcing material after crushing at the end face of the bumper reinforcing material (more precisely, the cross-sectional height excluding the thickness of both flanges) is the length of the middle rib 6 in the front-rear direction. The cross-section height other than the end face is larger than the length in the front-rear direction of the middle rib 6 in the entire length in the vehicle width direction of the crushed portion. Has not occurred.

As described above, in the bumper reinforcing material, by reducing the cross-sectional height of the end portion of the bumper reinforcing material by press crushing, the end mounting portion does not decrease the section modulus in the vicinity of the center where bending strength is required. Neighboring space reduction has been achieved. In addition, the cross-sectional height of the end part of the bumper reinforcement material that has been crushed is equal to or greater than the longitudinal length of the middle rib, so that deformation of the middle rib in the crushing process is suppressed, and collision with the bumper reinforcement end part It is possible to prevent the deformation strength from being lowered.
Further, in the above-mentioned bumper reinforcement, bending points 9 and 10 are provided on the inclined walls 7 and 8 and the webs 4 and 5 of the aluminum alloy extruded profile, so that the bending points 9 and 10 are bent at the press crushing process. Deformation (bending) easily occurs, a stable deformed shape can be easily obtained without using a mandrel tool, and it is possible to deal with low cost and mass production.

  In addition, when the crease point 9 is not provided in the slant walls 7 and 8 that connect the middle rib 6 and the collision side flange 3 (see FIG. 8 to be described later), the slant walls 7 and 8 fall down due to the press crushing process and collide. The side flange 3 is displaced so as to protrude in the vertical direction of the vehicle body. When there is a bolt mounting portion for the vehicle body or stay directly under the crushing portion, the bolting work hole provided in the collision side flange 3 is also displaced in the vertical direction of the vehicle body by crushing processing. On the other hand, the vehicle body side flange 2 having a joint hole (bolt hole) with the vehicle body (side member) or the stay 1 is not displaced so much, so that the positions of the work hole and the bolt hole are shifted and workability in bolt joining is deteriorated. . For this reason, when the attachment part with a vehicle body or a stay exists in the vicinity or directly under a crushing part, it is desirable to provide the slant walls 7 and 8 with the crease 9 which becomes a concave inside a cross section. However, regardless of the presence or absence of a break point, the cross-sectional height after crushing of the end portion in the vehicle width direction is set so as to be equal to or greater than the longitudinal length of the middle rib 6, thereby deforming the middle rib. Is suppressed, and the required strength at the time of an end collision can be secured.

  Further, when the break point 10 is provided so that the central part of the webs 4 and 5 protrudes to the outside of the cross section like the bumper reinforcing material, there is a bolt mounting part with the vehicle body or stay in the vicinity of or just below the crushing part. Even in this case, it can be said that the webs 4 and 5 after crushing do not interfere with the bolt joining work space W and are more preferable. If the width of both flanges 2 and 3 (width in the vertical direction) is sufficiently wide and a sufficient working space can be secured even if the webs 4 and 5 are deformed inside the cross-section, the flanges 2 and 3 are projected to the inside of the cross-section. A break point may be provided (see FIG. 3 described later).

  The bolt joint surface with the vehicle body (side member) or stay is preferably not deformed in the press crushing process. In the bumper reinforcing material, the end of the middle rib 6 on the vehicle body side is connected to the vehicle body side flange 2, and the collision side end of the middle rib 6 is connected to the collision surface side flange 3 via the inclined walls 7 and 8. Therefore, the deformation in the crushing process mainly occurs on the side of the bumper reinforcing material on the collision side flange 3, and the deformation amount of the vehicle body side flange 2 that becomes the bolt joint surface can be suppressed. However, the collision side end of the intermediate rib 6 is connected to the collision side flange 3 and the end of the intermediate rib 6 on the vehicle body side is connected to the vehicle body side flange 2 through the inclined wall, or the collision of the intermediate rib 6 An embodiment in which the end on the side is connected to the collision side flange 3 via the inclined wall and the end on the vehicle body side of the middle rib 6 is connected to the vehicle body side flange 2 via the inclined wall (see FIG. 4 described later) It is included in the present invention.

  In the bumper reinforcing material, since the webs 4 and 5 are provided with four folding points 10, one wall surface 4a, 5a, There are 4b and 5b. This makes it difficult for the bending moment to be transmitted to the flanges 2 and 3 during the crushing process, so that the shape accuracy of the flanges 2 and 3 is easily secured. However, the number of break points in the present invention is not limited to four.

  Further, the flanges 2 and 3 of the bumper reinforcing material are not provided with a protruding flange portion that protrudes from the connecting portion with the webs 4 and 5 to the vehicle upper and lower sides, but it is preferable to provide this (see FIG. 7 described later). reference). By providing this projecting flange portion, the surface of the web near the flange connecting portion is prevented from being rotationally deformed. That is, it can be said that it is effective in preventing the deformation of the flange due to the crushing deformation.

Another advantage of the bumper reinforcement of the present invention is improved bending workability. When a so-called end-bending structure bumper provided with a bent portion D (see FIG. 1) inside the stay 1 (in the vehicle width direction) like the bumper reinforcement, the collision side is crushed. Therefore, the bending angle can be reduced. As a result, the stress applied to the flanges 2 and 3 at the bending portion D is reduced, and there is an advantage that wrinkles and breakage are less likely to occur.
For example, a 6000 series or 7000 series aluminum alloy can be used as the aluminum alloy extruded profile used for the bumper reinforcing material.

So far, the structure of the bumper reinforcement according to the present invention has been described with reference to FIGS. 1 and 2, but hereinafter, another structure of the bumper reinforcement according to the present invention will be described with reference to FIGS. In addition, in FIGS. 3-9, the same number is provided to the site | part equivalent to the thing of FIG. As in FIG. 2, the cross-sectional shape (cross-section C) of the CC cross section is indicated by a solid line, and the shape of the AA end face (cross-section A) is indicated by a virtual line.
The bumper reinforcing material (cross section C) shown in FIG. 3 is only the point that the fold points 10 are provided in such a manner that the web central surfaces 4c and 5c constituting a part of the webs 4 and 5 protrude inside the cross section. Different from the bumper reinforcement shown in FIG. When this bumper reinforcing material is crushed (cross section A), the web center surfaces 4c and 5c of the webs 4 and 5 are deformed so as to protrude inside the cross section, and as described above, the bolt joining work space W is slightly narrower. Become.

  In the bumper reinforcing member (cross section C) shown in FIG. 4, the end on the collision side of the intermediate rib 6 is connected to the collision side flange 3 via the inclined walls 7 and 8, and the end on the vehicle body side of the intermediate rib 6 is the inclined wall. 11 and 12 (similar to the sloping walls 7 and 8, each having a substantially V-shaped cross section and having one fold point) and the slant walls 7, 8, 11, 12 differs from the bumper reinforcing material shown in FIG. 2 only in that the total length of 12 is equivalent to the longitudinal length of the inclined walls 7 and 8 of the bumper reinforcing material shown in FIG. When this bumper reinforcing material is crushed (cross section A), the collision-side flange 3 is easily deformed, and the shape accuracy is lowered when the collision-side flange 3 is used as a bolt joint surface. In this respect, the bumper shown in FIG. Reinforcement is better.

  The bumper reinforcing material (cross section C) shown in FIG. 5 differs from the bumper reinforcing material shown in FIG. 2 only in that the number of break points 10 of the webs 4 and 5 is three. When this bumper reinforcement material is crushed (cross section A), the U-shaped deformation of the webs 4 and 5 occurs in the vertical direction of the vehicle body because the folds on both sides are the ends and the center folds are the vertices. Is larger than the bumper reinforcement shown in FIG. 2 in which four break points are provided (increase in the overhang amount is indicated by ΔT in FIG. 5). In addition, since the bending angle at the break point (bent portion) becomes sharp and the risk of breakage increases, four break points 10 are desirable.

  The bumper reinforcing material (cross section C) shown in FIG. 6 is different from the bumper reinforcing material shown in FIG. 2 only in that the number of break points 10 of the webs 4 and 5 is two. When this bumper reinforcement is crushed (cross section A), bending moments are directly applied to the flanges 2 and 3 in accordance with the falling deformation of the surfaces 4d, 5d, 4f and 5f constituting the webs 4 and 5, and four break points are formed. The shape accuracy of the flanges 2 and 3 is likely to deteriorate compared to the bumper reinforcement shown in FIG. For this reason, it is desirable to suppress the deformation of the flanges 2 and 3 by using the protruding flange shown in FIG.

  The bumper reinforcing material (cross section C) shown in FIG. 7 is the bumper reinforcement shown in FIG. 2 only in that the flanges 2 and 3 have protruding flanges 13 projecting from the connecting portions with the webs 4 and 5 to the vehicle upper and lower sides. Different from the material. By providing the protruding flange 13, when the bumper reinforcing material is crushed (cross section A), the surface of the web 4, 5 near the connection portion with the flange 2, 3 is prevented from being rotationally deformed. That is, it is effective in preventing the distortion deformation of the flanges 2 and 3 due to the crushing deformation.

The bumper reinforcing material (cross section C) shown in FIG. 8 (reference example) is different from the bumper reinforcing material shown in FIG. 2 in that no creases are formed in the webs 4 and 5 and the inclined walls 7 and 8. For this reason, when the bumper reinforcing material is crushed (cross section A), the slant walls 7 and 8 are collapsed and deformed so that the collision side flange 3 protrudes in the vertical direction of the vehicle body, and is connected to the collision side flange 3 for bolt connection. When the working hole 14 is provided (the part indicated by the double arrow in FIG. 8), the working hole 14 is also displaced in the vertical direction of the vehicle body. On the other hand, since the vehicle body side flange 2 having the bolt hole 15 (the portion indicated by the double-headed arrow in FIG. 8) to be joined to the vehicle body (side member) or the stay is not displaced so much, the positions of the work hole 14 and the bolt hole 15 are greatly shifted. (The work direction is indicated by a single arrow E), the workability in the bolt joining deteriorates. Moreover, the shape accuracy of both flanges 2 and 3 deteriorates. For this reason, in these structures, it is desirable not to provide a bolt joint portion with the vehicle body or the stay in the vicinity of the crushing portion. In addition, particularly when a fold point is not provided on the inclined wall, there is a problem that the middle rib is likely to be deformed when the part is collapsed. From the viewpoint of preventing deformation of the middle rib, it is desirable to provide a break point on the inclined wall.

  The bumper reinforcing material (cross section C) shown in FIG. 9 is different from the bumper reinforcing material shown in FIG. 2 in that no creases are formed on the webs 4 and 5. When this bumper reinforcing material is crushed (cross section A), the amount of web 4 and 5 overhanging in the vertical direction of the vehicle accompanying press crushing increases (increase in the amount of overhang is indicated by ΔT in FIG. 9), The bending angle of the bent portion becomes sharp and the risk of breakage increases. At the same time, a bending moment is directly applied to the flanges 2 and 3 in accordance with the falling deformation of the webs 4 and 5, and the flanges 2 and 3 are liable to fall. Note that the same deformation occurs even when there is one break point, and the amount of web protruding in the vertical direction of the vehicle body is the largest.

The overhang of the cross section in the vehicle vertical direction accompanying the crushing process is not very preferable from the viewpoint of shape restriction. For this reason, it is desirable to provide two or more break points on the web to limit the amount of overhang. More preferably, by providing three or more bending points, it is desirable to prevent the bending moment accompanying crushing from being directly applied to the flange and to ensure the shape accuracy of the flange.
For the bumper reinforcement shown in FIGS. 8 and 9, the cross-sectional height after crushing of the end portion in the vehicle width direction is set to be equal to or greater than the longitudinal length of the middle rib 6. The deformation of the middle rib is suppressed, and the required strength at the end collision can be ensured.

  Next, for the bumper reinforcement made of extruded aluminum alloy, the cross-sectional shape after crushing when the vicinity of the stay mounting portion at the end was pressed from the collision side was analyzed by the finite element method (FEM). The analysis conditions are assumed to be a T1-treated material of an Al—Zn—Mg-based aluminum alloy extruded shape as the material of the bumper reinforcement, and the cross-sectional shape thereof is the shape shown in FIGS. As shown in FIG. 11, a 300 mm extruded profile 16 is placed on a surface plate 17, the left end is fixed, and a flat tool 18 tilted at an inclination angle of 13 degrees so that the fixed side is on from the collision surface side. The moving amount Z after the flat tool 18 contacts the extruded shape member 16 is set to 20 mm.

  The cross-sectional shape of the extruded shape member 16 is that the size of the closed cross section is 60 mm × 110 mm, the protruding length of the protruding flange is 5 mm, and the middle rib is connected to the end on the vehicle body side to the body side flange and the length is 40 mm. Set. In the cross section of FIG. 10 (a), the middle rib is connected to the collision side flange via upper and lower oblique walls (consisting of a curved wall surface) having a cross-sectional groove shape that expands toward the opening side toward the opening side. In the cross section of (b), it is connected to the collision side flange through upper and lower inclined walls having no break point, and in the cross section of (c), the collision side is connected through the upper and lower inclined walls each having one break point. Connected to the flange. 10 (a) to 10 (c), the numerical value with R is the radius of the arc, the numerical value with L is the length between them, the numerical value with S is the distance between them, and the numerical value with t is the thickness in the range of the double arrow. It means thickness and the unit is mm. In addition, the thickness of the part which has not entered the numerical value is all set to 2.0 mm. Note that modeling of the cross-sectional shape in the FEM analysis is performed in the shape of the thickness center. Therefore, the above dimension values are all values collected at the thickness center, and the flange thickness is ignored.

12 (a) to 12 (c) show the analysis results at the place where the crushing process of 20 mm was performed (the place at the right end of the extruded shape member 16 in FIG. 11). FIGS. 12A to 12C correspond to the cross sections of FIGS. 10A to 10C, respectively. In FIG. 12, the same parts as those in FIG. 2 are given the same numbers.
As shown in FIG. 12, in (a), the collision side flange 3 is displaced in the left and right direction and the webs 4 and 5 are projected in the left and right direction, but the middle rib 6 is deformed in a U shape. Absent. Even in (b), the displacement of the collision side flange 3 in the left and right direction is large, the webs 4 and 5 are overhanged in the left and right direction, the shape accuracy of the flanges 2 and 3 is lowered, and the cross-section of the middle rib 6 Although the deformation has occurred, the U-shaped deformation is suppressed as compared with the conventional example in which the inclined walls 7 and 8 are not formed. In addition, the square-shaped deformation | transformation of the middle rib 6 is further suppressed in the location where the crushing process of less than 20 mm was performed. On the other hand, in the embodiment (c) of the present invention , the middle rib 6 is not deformed in a U-shape, the collision side flange 3 is displaced in the left and right direction, and the webs 4 and 5 are projected in the left and right direction relatively. The shape accuracy of the flanges 2 and 3 is relatively good.

It is a top view of the bumper reinforcement material which concerns on this invention. It is the CC sectional view (solid line) and AA sectional view (imaginary line). It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the bumper reinforcement which is a reference example of this invention. It is sectional drawing of the other bumper reinforcement material which concerns on this invention. It is sectional drawing of the extruded shape material before the crushing process used for the analysis of the cross-sectional shape after a crushing process. It is a figure explaining the crushing method used for the analysis of the cross-sectional shape after crushing. It is sectional drawing of the extrusion shape material before a crushing process used for the analysis of the cross-sectional shape after a crushing process, and sectional drawing after a crushing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stay 2 Collision side flange 3 Car body side flange 4 Upper web 5 Lower web 6 Middle rib 7, 8, 11, 12 Slanted wall 9, 10 Folding point 13 Projection flange

Claims (6)

Body side and collision side flanges that are spaced apart in the longitudinal direction of the vehicle body, upper and lower webs that are spaced apart in the vertical direction of the vehicle body and connect the two flanges, and front and rear webs A cross-sectional groove shape that is connected to at least one middle rib whose length in the direction is shorter than the front-rear direction interval between the two flanges, and a vehicle body side and / or a collision side end of each middle rib and connects the flanges together with the middle rib. The upper and lower inclined walls each have one or more fold points that are concave in the cross-section inward direction, and the groove shape is expanded toward the opening side and closed. The end is connected to the end of the middle rib, and the open end is made of an aluminum alloy extruded shape connected to the vehicle body side or the flange on the collision side, and the collision side at both ends in the vehicle width direction is crushed toward the vehicle body side Along with crushing Automotive bumpers reinforcement section height Engineering been portion is characterized in that medium or larger than the front-rear direction length equivalent to the ribs. The bumper reinforcement for automobiles according to claim 1 , wherein the web has two or more break points at an intermediate position. The bumper reinforcement for automobiles according to claim 2 , wherein the web is provided with four break points. The bumper reinforcing material for automobiles according to any one of claims 1 to 3 , wherein a central portion of the web projects outward from the cross section. Connected to the middle rib vehicle body side end vehicle body side flange of any of claims 1 to 4, wherein the end of the collision side of the middle rib, characterized in that connected to the collision side flange through the upper and lower oblique wall The bumper reinforcement for automobiles described in the above. 6. The bumper reinforcing material for an automobile according to claim 1 , wherein the flange has a protruding flange portion projecting in a vertical direction of the vehicle body from a connection portion with the web.

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