JP5203870B2 - Automotive body reinforcement with excellent bending crush characteristics - Google Patents

Description

  The present invention has high bending strength and energy absorption characteristics with respect to a bending load at the time of a vehicle collision as a bending crushing characteristic, such as a bumper reinforcing material and a door guard bar, which are excellent in collision safety without providing a reinforcing material separately. The present invention relates to an aluminum alloy automobile body reinforcement. Hereinafter, aluminum is also referred to as Al.

  As is well known, many automobile body reinforcements such as bumper reinforcements and door guard bars are provided on the automobile body. For example, inside a bumper attached to the front end (front) and rear end (rear) of an automobile body, as is well known, a bumper reinforcement as a strength reinforcement (also called bumper reinforcement or bumper armature) Is provided. The bumper reinforcing member has a substantially rectangular cross-sectional shape, and as is well known, 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 parallel to the vehicle width direction. The bumper and the stay or the crash box behind the bumper constitute an energy absorbing member against the collision of the vehicle body.

  The support structure of the bumper reinforcing material is a vehicle body frame such as a front side member or a rear side member that extends in the vehicle body length direction from the rear surface with respect to the collision surface via a support member such as a hollow structure having a substantially rectangular cross section. Connected and fixed to. By adopting such a support structure, the bumper reinforcement member is crushed and deformed in the lateral direction (substantially horizontal direction) with respect to the collision of the vehicle body to absorb the collision energy and protect the vehicle body. In other words, the bumper reinforcement absorbs the applied external force energy (collision energy) by its own bending deformation and cross-sectional collapse (crushing) without damaging or scattering when a heavy load is applied at the time of a vehicle collision. The ability to deform and absorb load energy is required. Such functions and support structures are provided inside the doors to reinforce the doors in order to prevent the intrusion of the doors into the passenger compartment caused by a collision from the side of the vehicle body and protect the passengers. It is basically the same for other car body reinforcements such as door guard bars (door beams).

  In recent years, in order to reduce the weight of these reinforcing materials, high-strength aluminum alloy extruded shapes such as 5000 series, 6000 series, and 7000 series (having the same cross-sectional shape in the longitudinal direction) instead of conventionally used steel materials. Profile). An aluminum alloy is superior in energy absorption performance in the case of the same weight as compared with steel or the like. Moreover, an aluminum alloy extruded shape having the same cross-sectional shape in the longitudinal direction can efficiently and in large quantities produce a hollow structure having a substantially rectangular cross-sectional shape with excellent strength and rigidity. For this reason, it is suitable for a reinforcing material as an energy absorbing member for a vehicle body.

  However, when such aluminum alloy reinforcements are used as reinforcements such as bumper reinforcements for automobiles, there are various types of collision tests such as pole collision, barrier collision, offset collision, etc., and safety against these collisions is improved. Therefore, there is an increasing need to increase the strength characteristics of the reinforcing material. For example, in the case of a pole collision as one problem in the present invention, the load from a substantially horizontal direction is concentrated locally, so that the crushing strength of a bumper reinforcement or the like tends to be insufficient. There is a problem that the crushing strength is insufficient.

  More specifically, the behavior of an aluminum alloy reinforcing material at the time of a vehicle body pole collision as a bumper reinforcing material will be described with reference to the vehicle body plan view of FIG. As shown in FIG. 7A, when the vehicle body A travels and collides with C, which is a fire hydrant, a utility pole, a gate pole, etc., the load on the rear bumper reinforcing material 110 from the substantially horizontal direction. However, it is concentrated locally at the collision part. The same applies to the front bumper reinforcement. In this case, if the load is large, the crushing strength of the bumper reinforcing material 110 is insufficient, and the bumper reinforcing material 110 is bent in the horizontal direction from the center as shown in FIG. Arise. Depending on the magnitude of the load, the bumper reinforcement is a type of reinforcement in which the aluminum alloy bumper reinforcement material is reinforced by not only the mouth shape but also the cross-sectional shape of a daily shape, or an intermediate rib such as an eye shape or a square shape. There is also a great deal of potential for material.

  On the other hand, in order to prevent the bending at the time of the pole collision, it is necessary to increase the crushing strength of the bumper reinforcing material. For this purpose, the aluminum alloy hollow shape material itself constituting the vehicle body reinforcement material such as a bumper reinforcement material is strengthened, the thickness of the hollow shape material wall portion is increased, the width of the reinforcement material is increased, etc. A method is conceivable. However, when the strength of the aluminum alloy hollow shape is increased, it is difficult to manufacture the shape such as extrusion and the forming of the shape such as bending, and the crack is likely to occur. On the contrary, the energy absorption amount of the collision is reduced. There is a limit because it leads to things. In addition, when the thickness of the aluminum alloy hollow shape member is simply increased or the width of the reinforcing member is increased, the weight increases, and the advantage of weight reduction by the aluminum alloy is impaired.

  Therefore, conventionally, as a countermeasure against a pole collision, there has been a method in which a reinforcing material is attached to a central portion in the longitudinal direction where the bumper reinforcing material is easily bent, and the central portion is reinforced. Actually, a reinforcing member such as aluminum or steel is attached to the front side of the vehicle body on the collision surface side of the bumper reinforcing member. However, in order to obtain a sufficient reinforcing effect, disadvantages such as an increase in weight due to the attachment of the reinforcing member and an increase in the number of parts and the cost for attachment cannot be ignored. Accordingly, the weight of the steel bumper reinforcing material is not greatly different from that of the steel bumper reinforcing material, and the advantage of weight reduction by adopting the aluminum alloy for the bumper reinforcing material is impaired.

  On the other hand, it has been conventionally proposed that the reinforcing shape is made of an aluminum alloy instead of steel. For example, a reinforcing structure is disclosed in which a reinforcing body formed of an aluminum alloy hollow shape material is bonded and fixed to the central portion in the longitudinal direction of a bumper reinforcing material with an adhesive or the like (see Patent Document 1). Furthermore, an aspect in which the cross section of the aluminum alloy reinforced shape member has an open cross section and is provided on the front side of the bumper reinforcing material has been proposed (see Patent Document 2). A bumper reinforcing material made of an aluminum alloy hollow material having a substantially rectangular cross section that can be reinforced using an existing bumper space has also been proposed (see Patent Document 3). In this proposal, a reinforcing profile that is shorter than the bumper reinforcement and has a substantially rectangular cross-section is placed substantially parallel to the bumper reinforcement on either the upper side or the lower side of the central portion in the longitudinal direction of the bumper reinforcement. Attach to a single unit.

In addition, in order to increase energy absorption performance and crushing strength at the time of offset collision, it is not compatible with pole collision, but a concave part is provided in the center part of the front wall such as an aluminum alloy hollow shape member having a substantially square cross section. It is known (see Patent Documents 4 and 5). These concave portions at the center of the front wall reduce the wall width of the vertical wall as the collision surface of the front wall (hereinafter also simply referred to as the wall width) from the wall width of the original vertical wall surface. This reduces the width-to-thickness ratio (wall width / wall thickness) of the front wall and increases the crushing strength of the front wall of the bumper reinforcement.
JP-A-6-286536 Japanese Patent Laid-Open No. 2001-225663 JP 2004-262300 A JP 2001-26245 A Japanese Patent Laid-Open No. 2002-225652

  However, even when these conventional reinforcements are installed, the bumper reinforcement's crushing strength has been improved against pole collision resistance, which has become a stricter collision test standard, such as a higher collision speed during a collision test on the bumper reinforcement. Is lacking. That is, the bending strength with respect to the bending load at the time of vehicle collision is insufficient. In addition, these conventional reinforcing material attachments require a space for attaching the reinforcing material inside the bumper with little space. For this reason, when the reinforcing material is attached to the bumper reinforcing material, it is necessary to change the design of the bumper or the automobile body to secure this space. Therefore, in the design of a bumper or an automobile body, if a space cannot be secured even if this design change or design change is made, a reinforcing material made of an aluminum alloy or the like cannot be employed.

  On the other hand, the above-described method of providing a recess in the center of the front wall to reduce the width-to-thickness ratio (wall width / wall thickness) of the front wall and increasing the crushing strength of the front wall of the bumper reinforcement material will still cause a collision The crushing strength of the bumper reinforcement is insufficient for the pole collision resistance, which has become stricter on the test standards. In other words, the bending strength with respect to the bending load at the time of vehicle collision is insufficient.

  Further, the bumper reinforcing material is required to have high energy absorption characteristics in addition to the improvement of the crushing strength at the time of the vehicle body collision. In other words, with respect to the load applied at the time of a vehicle collision, the reduction in the load after the maximum load is suppressed, and the energy absorption amount defined by the integration of the load and the deformation amount when greatly deformed is increased, so that the vehicle body is damaged. It is also required to have an energy absorption characteristic of reducing the above. Such a characteristic is provided not only for the bumper reinforcement, but also inside the door in order to protect the occupant by preventing the intrusion of the door into the passenger compartment when it is collided from the side of the vehicle body. Commonly required for automobile body reinforcements such as door guard bars (door beams) that reinforce doors.

  Accordingly, automobile body reinforcing materials are increasingly required to have high bending strength and energy absorption characteristics with respect to bending loads at the time of a vehicle collision as bending collapse characteristics. An object of the present invention is to provide an automotive body reinforcing material made of aluminum alloy such as a bumper reinforcing material and a door guard bar, which has a high bending crushing property and is excellent in collision safety without providing a reinforcing material separately. Is.

In order to achieve the above object, the gist of the present invention consists of an aluminum alloy hollow shape member having a substantially rectangular cross section, and has the following configurations a to d, and has improved pole collision resistance. It is an automobile body reinforcement material with excellent bending crushing characteristics.
a. The substantially rectangular cross section connects the front wall extending substantially in the vertical direction, the rear wall extending substantially in the vertical direction substantially parallel to the front wall and spaced apart, and the front wall and the rear wall, An approximately Japanese shape consisting of upper and lower lateral walls extending in a substantially horizontal direction at intervals, and intermediate walls extending in a substantially horizontal direction by connecting the central portions of these front and rear walls. It consists of a cross section.
b. The thickness of the front wall and the rear wall is 3 mm or more and 4.6 mm or less respectively , while the thickness of the upper and lower horizontal walls and the intermediate wall is thinner than the thickness of the front wall and the rear wall. And
c. The upper and lower lateral walls are connected to the front and rear walls by connecting the upper and lower portions of the front and rear walls, respectively, below or above the upper and lower ends of the front and rear walls. The wall and the rear wall are partitioned, and both end portions of the front wall and the rear wall are flange portions projecting in the vertical direction, the length of the flange portion is Wd, and the wall width of the rear wall is Wb The ratio Wd / Wb between the two is in the range of 0.08 to 0.1 .
d. The length of the intermediate wall on the front wall side is made shorter than the length of each of the upper and lower lateral walls, and the connection between the front wall side end of the intermediate wall and the front wall central portion is made to reduce the wall width of the front wall. In this manner, a concave portion extending in the longitudinal direction of the automobile body reinforcing material is formed in the central portion of the front wall.

  In the vehicle body reinforcing material configuration of the present invention, the crushing strength of the reinforcing material front wall is first increased by making the front wall and the rear wall relatively thick based on the requirement of b. Next, according to the requirement d above, first, the wall surface of the front wall facing the collision direction is a curvature surface, but it does not protrude in the collision direction (not convex in the collision direction) but is concave on the rear wall side. By using the surface, the crushing strength of the front wall of the reinforcing material is increased. Further, according to the requirement d and the requirement c, the wall width of the front wall is reduced and the width-thickness ratio (wall width / wall thickness) is reduced, thereby increasing the crushing strength of the front wall of the reinforcing material. Further, according to the requirement c, the wall width of the rear wall is also reduced, and the crushing strength of the rear wall of the reinforcing material is increased by reducing the width-thickness ratio (wall width / wall thickness).

  Therefore, in the vehicle body reinforcing material configuration of the present invention, the bending strength of the reinforcing material is improved by the effect of improving the crushing strength of the front wall and the rear wall, and the pole material is substantially horizontal with respect to the reinforcing material at the time of a pole collision. Even if the load is applied locally and concentrated on the collision part, it does not easily buckle or bend. In addition, since the decrease in the reaction load after the maximum load is generated is relatively small, the energy absorption amount per deformation amount is increased, and the vehicle body damage can be reduced. Furthermore, the effect excellent in the pole collision property can be achieved similarly to the case where the reinforcing material is provided separately without providing the reinforcing material separately. In addition, in the collision other than the pole collision and in the automobile body reinforcing material other than the bumper reinforcing material, the bending crushing characteristics can improve the bending strength and the energy absorption characteristics with respect to the bending load at the time of the vehicle body collision. As a result, it is possible to provide a vehicle body reinforcing material that is highly safe, lightweight, and space-saving with respect to automobile crash test standards that tend to be more severe.

  Hereinafter, a more specific embodiment of the present invention will be described in detail with reference to the drawings, with a bumper reinforcement as an automobile body reinforcement and a pole collision resistance as a representative example.

(Bumper reinforcement overall shape and structure)
Embodiments of the Al alloy bumper reinforcement are illustrated in perspective views in FIGS. FIG. 4 is a plan view of FIGS. Here, FIGS. 1, 2, and 4 show a state in which the bumper reinforcing member 20 extends in a substantially horizontal direction in the vehicle width direction. The longitudinal shape of the bumper reinforcement member 20 is not linear in terms of vehicle body design, whether it is front or rear, and as shown in FIGS. 2 has a curved shape bent rightward and downward in FIG. In the curved shape shown in FIGS. 1, 2, and 4, the bumper reinforcing member 20 has straight (left and right) curved portions 20b and 20b at both ends and a central straight portion 20a.

  Note that the bumper reinforcing material of the present invention has a curved shape in the longitudinal direction, and may have linear or curved curved portions (bent portions) at both ends in the longitudinal direction. It may be curved. Further, the longitudinal direction may be linear without being curved.

  As shown in FIG. 4, the bumper reinforcing member 20 of the present invention has hollow cylindrical stays on the back surfaces (back surfaces) of the curved portions 20 b and 20 b at both ends (right and left), as in a normal bumper reinforcing material. 30, 30. The bumper reinforcing member 20 is supported on the vehicle body side by being connected to a vehicle body side member (not shown) through the stays 30 and 30, whether it is front or rear.

stay:
In FIG. 4, flanges 31 and 32 are provided on the front and rear surfaces of the stays 30 and 30, respectively, and the front side flange 31 is welded to the back surfaces (back surfaces) of the curved portions 20 b and 20 b of the bumper reinforcing material 20. Mechanically joined. The rear flange 30 is welded or mechanically joined to a front flange of a side member (not shown). Here, as shown in FIG. 4, these stays are joined to a bumper reinforcing material having curved portions bent at both ends of the vehicle body. As shown in FIG. 4, the front wall is a linear or curved inclined wall or inclined wall corresponding to the rear surface of the curved portion of the bumper reinforcement.

  Each of the stays 30 and 30 may be made of steel or Al alloy. However, in order to reduce the weight of the stay, it is preferable that the stay itself is also a hollow cylinder or shape. As for the material, steel materials such as ordinary steel and high tensile steel, and aluminum alloy extruded shapes are appropriately selected. Furthermore, the bumper reinforcing material of the present invention is integrated with the stay in advance and used as a bumper reinforcing material with a stay, so that it is extremely easy and simple to attach to the side member via the stay.

(Cross-sectional shape of bumper reinforcement)
Requirement a:
The cross-sectional shape and structure of the bumper reinforcing member 20 (hollow shape member) are premised on a substantially rectangular cross section (closed cross section) composed of a substantially Japanese cross section as shown in FIGS. Consists of. 1 and 2 are cross sections (side cross sections) of a front or rear bumper reinforcing member 20 (hollow shape member) as viewed from the side of the vehicle body (left side).

  First, the cross-section of the vehicle is substantially the same as the front wall 1 extending in the vertical direction (in FIG. 1) of the vehicle body, and substantially parallel to and spaced from the front wall 1 in the vertical direction of the vehicle body (in FIG. 1). The rear wall 2 extends in the direction (substantially vertical direction). The front wall 1 erected against the collision direction or the collision load F is also referred to as a front vertical wall, a collision side wall, a front flange, or the like. Further, the rear wall 2 located on the rear side (right side in FIG. 1) at a predetermined interval from the front wall 1 is also referred to as a rear vertical wall, a rear flange, or the like.

  Next, in addition to the front wall 1 and the rear wall 2, each of the substantially cross-sections of the upper part (upper part) 1 c and 2 a and the lower part (lower part) 1 d and 2 b of the front wall 1 and the rear wall 2 is next. The upper and lower lateral walls 3 and 4 extend in a substantially horizontal direction with a space therebetween. The end portions of the horizontal walls 3 and 4 are orthogonal to the upper portion 1c and the lower portion 1d of the front wall 1 and the upper portion 2a and the lower portion 2b of the rear wall 2 at 3a and 3b in the horizontal wall 3 and at 4a and 4b in the horizontal wall 4, respectively. Yes. These lateral walls 3 and 4 are also referred to as side walls, webs and the like.

  The substantially cross section is further composed of an intermediate wall (intermediate lateral wall) 5 that connects the central portions 1e and 2c of the front wall 1 and the rear wall 2 and extends in a substantially horizontal direction. The end portions 5a and 5b of the intermediate wall 5 are orthogonal to the central portions 1e and 2c of the front wall 1 and the rear wall 2 that are erected in a substantially vertical direction. The intermediate wall 5 is also referred to as a middle rib or a reinforcing wall. As a result, the bumper reinforcing member 20 (hollow shape member) has a substantially cross-section with a closed cross-sectional structure having two upper and lower hollow portions 11 and 12.

Requirement b:
Here, in the configuration of the bumper reinforcing material according to the present invention, as described in the requirement b, first, the thickness of the front wall 1 and the rear wall 2 is set to be relatively thick, each 3 mm or more, so that the front surface of the bumper reinforcing material is obtained. The crushing strength between the wall 1 and the rear wall 2 is increased. Unless the front wall 1 and the rear wall 2 are each relatively thicker than 3 mm, the pole impact resistance of the aluminum alloy reinforcing material itself is equal to that provided with the reinforcing material, regardless of the cross-sectional shape. Can't improve. However, in the bumper reinforcing material, if the thicknesses of the front wall 1 and the rear wall 2 are 4 mm or less respectively, the pole collision resistance may be insufficient in some cases. Preferably, the front wall 1 and the rear wall 2 The thickness of each is 4 mm or more, which is thicker. At this time, the thickness of the front wall 1 and the rear wall 2 may be the same or different from each other.

  On the other hand, the thicknesses of the upper and lower lateral walls 3 and 4 and the intermediate wall 5 are not as effective in resistance to pole collision as the thicknesses of the front wall 1 and the rear wall 2. Therefore, it is only necessary to have a strength sufficient to withstand the concentrated load applied when the pole collides, and the wall thickness can be reduced compared to the front wall 1 and the rear wall 2. Further, in order to reduce the weight of the bumper reinforcement, it is preferable that the upper and lower lateral walls 3, 4 and the intermediate wall 5 are thinner than the front wall 1 and the rear wall 2. In this regard, when the thickness of the front wall 1 and the rear wall 2 is 4 mm or more as a bumper reinforcing material, preferably, the thicknesses of the upper and lower lateral walls 3 and 4 and the intermediate wall 5 are 2 to 3.5 mm.

Requirement c:
As shown in FIGS. 1 and 2, the bumper reinforcing member 20 (hollow shape member) includes the front wall 1 by the upper and lower lateral walls 3 and 4 as described above in addition to the substantially sun-shaped cross section. The original single wall width (length) between the rear wall 2 and the rear wall 2 is partitioned (divided) at both the upper and lower ends thereof, and flanges are provided.

  That is, the upper and lower lateral walls 3, 4 are not upper and lower ends 1 f, 1 g, 2 d, 2 e of the front wall 1 and rear wall 2, but upper and lower ends of the front wall 1 and rear wall 2. The upper and lower walls 1c and 2a and the lower portions 1d and 2b of the front wall and the rear wall, respectively, are connected to each other. Thereby, the front wall 1 and the rear wall 2 are partitioned (divided) by 1c and 2a, 1d and 2b which are also orthogonal portions (intersections) with the respective lateral walls 3 and 4, and the front wall 1 and the rear wall 2 are separated from each other. The flanges 6, 7, 8, and 9 project from both ends (up to 1 c to 1 f, up to 1 d to 1 g, up to 2 a to 2 d, up to 2 b to 2 e). Thus, in the present invention, the original front wall 1 and the rear wall 2 are divided (divided) into the original front wall 1 and the rear wall 2 vertically by the upper and lower lateral walls 3 and 4. Thus, the flanges 6, 7, 8, and 9 are projected in the vertical direction from the positions of the upper and lower lateral walls 3 and 4, respectively.

  As described above, in the requirement c, the front wall 1 is divided (divided) into the front wall at the center, the upper (upper) flange 6 and the lower (lower) flange 7 in the vertical direction, and the rear wall 2 is also in the center. Are divided (divided) into a rear wall, an upper (upper) flange 8, and a lower (lower) flange 9, respectively. Thus, by dividing (dividing) the original single wall width of the front wall 1 and the rear wall 2 into upper and lower parts, the original wall width of the front wall 1 and the rear wall 2 is respectively changed up and down. Decrease by the length of both flanges. Moreover, the wall width of the upper and lower flanges, which are fixed ends, is also small. As a result, as described later, the crushing strength of the front wall of the bumper reinforcement is increased by reducing the width-thickness ratio (wall width / wall thickness).

Requirement d:
As shown in FIGS. 1 and 2, the bumper reinforcing material 20 (hollow shape member) is formed on the central portion 1e of the front wall 1 as shown in FIGS. The recessed part 10a extended over the longitudinal direction is formed. Here, the concave portion means a curvature surface that does not protrude in the collision direction of the arrow F (in the left direction in the figure) but is recessed in the rear wall 2 side (in the right direction in the figure).

  The concave portion 10a is formed by making the length of the front wall side 5a of the intermediate wall 5 shorter than the lengths of the upper and lower lateral walls 3 and 4 by 1 shown in FIG. Next, the front wall side end portion 5a of the intermediate wall 5 is connected to the front wall central portion 1e so as to reduce the wall width of the front wall 1, and the reinforcing material 20 is attached to the front wall central portion 1e. A recess 10a extending in the longitudinal direction is formed. More specifically, the central portion 1e of the front wall 1 is divided into upper and lower portions with the intermediate wall 5 (5a) as a boundary, and the divided (divided) central portions 1a and 1b between the upper side and the lower side are separated. However, each has a substantially arc shape extending rearward from the wall surface position of the front wall 1 and extending in the direction of the intermediate wall 5 (5a). The front wall 1a and the front wall 1b are formed so as to reduce the wall width of the front wall 1 so that the ends of the substantially arc-shaped front walls 1a and 1b intersect with the intermediate wall edge 5a. Here, the wall surface position of the front wall 1 is a horizontal position (in the left-right direction in the drawing) of the wall surface of the front wall 1 to be erected. The front walls 1a and 1b do not necessarily have the arc shape shown in FIGS. 1 and 2 and may be linear or other curved lines.

  According to the requirement of d, first, the wall surface of the front wall 1 facing the collision direction of the arrow F is a curvature surface, but by making the curvature surface concave to the rear wall 2 side, the crushing strength of the front wall of the bumper reinforcement is reduced. increase. The shape of the concave portion 10a, in other words, the arc shape of the central portion 1a, 1b between the upper side and the lower side of the front wall 1 is the condition of the concave portion described above, and does not protrude in the collision direction of the arrow F. If the curvature surface is concave, the shape necessary for increasing the crushing strength of the front wall is appropriately selected.

  For example, FIG. 2 is a perspective view showing an Al alloy bumper reinforcing material 21 which is another embodiment of the present invention. Here, the bumper reinforcing member 21 in FIG. 2 has almost the same cross-sectional structure as the bumper reinforcing member 20 in FIG. 1, but has a depth recessed toward the rear wall 2 side (to the right in the drawing) of the formed recess 10b. (Length l shown in FIG. 3) is larger than the recess 10a of FIG. That is, the length of the front wall 5a of the intermediate wall 5 is shorter than that of the intermediate wall 5 in FIG. 1, and the curvature of the arcs of the central portions 1a and 1b between the upper side and the lower side of the front wall 1 is smaller. Yes.

  Note that. The cross-sectional shapes of these bumper reinforcing members in the longitudinal direction are not necessarily the same, but a hollow shape whose cross-sectional shape changes partially or sequentially can be freely selected from the design side of the vehicle body. In addition, the shape and structure such as the whole and the size and length of each part are selected according to the required characteristics such as the size (height) of the cross section of the bumper reinforcement by the vehicle body design and the strength or impact energy absorption amount. Is done.

(Function and effect)
Using FIG. 3, as a bending crushing characteristic with respect to a vehicle body collision according to the requirements a to d of the present invention, a mechanism (action and effect) that improves bending strength and energy absorption characteristics with respect to a bending load at the time of a vehicle body collision will be described by taking a pole collision Let me explain. FIG. 3 shows a cross-section (a cross-sectional view as seen from the side of the vehicle body) of the same Al alloy bumper reinforcing material of the present invention as in FIG. This mechanism is also exhibited in other vehicle body reinforcements such as door guard bars and in other collision modes other than pole collision.

Front wall:
When a collision load indicated by an arrow F shown in FIG. 3 is applied to the front wall 1 due to a vehicle collision such as a pole collision, a bending load is applied to the cross section of the central portion of the reinforcing material. A compressive force in the direction perpendicular to the paper surface acts (the compressive force acts in the direction perpendicular to the paper surface in FIG. 3, that is, the longitudinal direction of the reinforcing member 20 and the vehicle body width direction). On the other hand, first, as the requirement b, the front wall 1 has a relatively thick thickness of 3 mm or more. Therefore, the crushing strength of the front wall 1 itself is improved by increasing the thickness.

  Next, as a requirement c, the front wall 1 is divided into upper and lower lateral walls 3 and 4 into a central front wall, an upper (upper) flange 6 and a lower (lower) flange 7 (divided vertically). And the original single wall width of the front wall 1 is divided (divided) vertically. Furthermore, the front wall 1 is formed with a concave portion 10 extending in the longitudinal direction of the bumper reinforcing material 20 in the central portion 1e of the wall surface 1e of the front wall 1 according to the requirement of d. The wall surface of the facing front wall 1 is a curvature surface.

  According to these requirements c and d, the wall width of the front wall 1 as a single undivided wall including the fixed end is the original vertical wall width Wb (the original wall width Wb of the rear wall 2). To 2 × Wa). That is, the vertical wall width (wall width) of the front wall 1 as the original collision surface is Wb, but the length Wd of each of the upper and lower flanges 6 and 7 (the length of each flange of the rear wall 2). The same as Wd), and reduced by the arc-shaped front walls 1a and 1b of the concave portion 10 at the central portion to 2 × Wa. Further, since the wall width of the upper and lower flanges 6 and 7 which are fixed ends of the front wall 1 is also partitioned by the upper and lower lateral walls 3 and 4, the wall width as a single wall is Wd. And become smaller.

  On the other hand, the wall thickness of the front wall 1 is increased by increasing the thickness of the front wall 1 according to the requirement b. Therefore, the width-thickness ratio (wall width / wall thickness) of the front wall 1 is greatly reduced together with the width-thickness ratio of the upper and lower flanges 6 and 7, and the front wall 1 and the front wall against the compressive force generated at the time of collision. The crushing strength of each of both ends (upper and lower flanges 6, 7) of 1 is increased.

  In addition, the length l of this recessed part 10 (10a of FIG. 1, 10b of FIG. 2) shown in FIG. 3, in other words, the depth (depth) 1 of the recessed part 10 from the wall surface position of a front wall is the above-mentioned front surface. The length necessary to increase the crushing strength of the front wall is appropriately selected depending on the arc shape of the central portions 1a and 1b between the upper side and the lower side of the wall 1. Due to this shape effect, the length of the intermediate wall 5 is shortened by 1 from L1 (L1-1), and as a result, the compressive force F applied from the front wall is transmitted to the rear wall 2 through the intermediate wall 5. The strength of the intermediate wall 5 that can withstand this load is improved.

  Further, the front wall 1 is formed with a concave portion 10a in the central portion 1e of the wall surface of the front wall 1, and the wall surface of the front wall 1 facing the collision direction of the arrow F is a curvature surface. In this way, by using a curvature surface that is recessed toward the rear wall 2 side, the bending crushing strength of the front wall of the bumper reinforcing material can be increased by the shell effect.

  On the other hand, if the curvature surface protrudes in the collision direction of the arrow F (to the left in the figure) as shown in FIG. 5, even if the other requirements described above are satisfied, Unlike the collision mode, in the case of a pole collision, where the load from the substantially horizontal direction is applied to the bumper reinforcement material in a concentrated manner on the collision part, the load is likely to concentrate on the part protruding outward, Crushing strength is insufficient. For this reason, as shown in FIG. 7 (b), the bumper reinforcing material is bent in the horizontal direction from the central portion, and the vehicle body may be damaged. Further, as shown in FIG. 6, when the flat upright surface is formed in the collision direction of the arrow F (to the left in the drawing) and the surface is not provided with a curvature, there is no concave portion. Since the width of the wall is larger than that of the present application and there is no strength improvement effect due to the curvature, the load decrease after the maximum load is earlier than that of the present application, resulting in a smaller energy absorption amount.

  As described above, due to the requirements b, c, and d, the crushing characteristics of the front wall 1 when bent are greatly improved including the upper and lower flanges 6 and 7, and the front wall 1 is crushed. The bending strength and energy absorption characteristics with respect to the bending load at the time of the vehicle collision are improved as the bending crushing properties against the vehicle collision such as the pole collision. In other words, it is possible to satisfy the collision safety and the light weight according to the stricter standards even for a pole collision in which loads from a substantially horizontal direction are locally concentrated and other collision forms. On the other hand, as in the case of FIGS. 5 and 6, even if any of these requirements b, c, d is missing, it is not possible to satisfy the collision safety and the light weight in the stricter standards.

Rear wall:
On the other hand, when a collision load indicated by an arrow F shown in FIG. 3 is applied to the rear wall 2 due to a pole collision, unlike the front wall 1 side, a tensile force acting in the direction perpendicular to the plane of FIG. Acts in the direction perpendicular to the plane of the paper, that is, in the longitudinal direction of the reinforcing member 20 and in the vehicle body width direction). However, a hollow member having a substantially rectangular structure having a closed cross section has not only this tensile force but also both ends (bumpers) of the rear wall 2 as a fixed end in a pole collision in which a load from a substantially horizontal direction is locally concentrated. In the reinforcing material, a compressive force acts on the support portion of the stay) (this compressive force acts in the direction perpendicular to the plane of FIG. 3, that is, the longitudinal direction of the reinforcing material and the vehicle body width direction). Unless the compressive force acting on both ends of the rear wall 2 is taken into consideration, the crushing strength of the rear wall 2 against a pole collision cannot be sufficiently increased.

  On the other hand, in the present invention, as in requirement c, the rear wall 2 is divided into the rear wall of the central portion, the upper (upper) flange 8, and the lower (lower) flange 9 by the upper and lower lateral walls 3, 4. And partitioning (dividing) the upper and lower sides of the original single wall width vertically (dividing). As a result, the original wall width Wb of the rear wall 2 is reduced by the length Wd of the lengths of the upper and lower flanges 8 and 9, respectively. Further, the wall width Wd of the upper and lower flanges 8 and 9 which are fixed ends of the front wall 1 is also reduced. As a result, the wall width of the rear wall 2 including the fixed end is reduced, while the wall thickness is increased by increasing the thickness of the rear wall 2 according to the requirement b. Therefore, the width-thickness ratio (wall width / wall thickness) of the rear wall 2 is greatly reduced together with the width-thickness ratio of the upper and lower flanges 8 and 9. Therefore, the crushing strength of the upper and lower flanges 8 and 9 with respect to the compressive force generated at the time of the collision of the pole is increased, and the crushing strength of the front wall 1 with respect to the tensile force generated at the fixed end at the time of the collision of the pole is also increased.

  By these requirements b and c, the crushing strength of the rear wall 2 is greatly improved including the upper and lower flanges 8 and 9, and even for a pole collision in which a load from a substantially horizontal direction is locally concentrated. The rear wall 2 is less likely to be crushed, and the bending collapse characteristics such as pole collision resistance and collision safety are greatly improved.

(Al alloy for bumper reinforcement)
The Al alloy used in the bumper reinforcing material of the present invention is preferably a high-strength Al alloy for the purpose of excellent resistance to pole collision while satisfying the weight reduction conditions. Moreover, it is preferable that it is Al alloy which is easy to extrude to a hollow shape material (it is easy to manufacture). As the Al alloy satisfying these required characteristics, general-purpose (standard) Al alloys having a relatively high yield strength such as 5000 series, 6000 series, and 7000 series, which are generally used for such structural member applications, are used. These Al alloy hot-extruded hollow shapes, which are Al alloy materials whose mechanical properties are tempered by solution quenching treatment, aging treatment or the like, are used.

  The bump collision resistance of the present invention bumper reinforcing material (invention example) shown in FIGS. 1 and 2 and the bumper reinforcing material (comparative example) shown in FIGS. did.

  Here, a collision experiment simulating a pole collision was conducted. That is, the initial buckling load, the load energy applied to the local area of the central part of the bumper reinforcement due to the collision of the central part of the bumper reinforcement with the pole-shaped rigid body having a radius of 127 mm on the front wall side. Absorption performance and bending moment were investigated. It is assumed that the vehicle weight at the time of actual collision is about 1.0 to 1.8 ton and the collision speed is 8 to 64 km / h. Here, a static compression experiment is performed.

  The cross-sectional shape of the bumper reinforcing material is as follows: wall width Wa of each front wall 1: 42.57 mm (FIG. 1), 43.46 mm (FIG. 2), wall width Wb of each rear wall 2: 150.0 mm, each bumper reinforcing material The width (length) L1: 65.0 mm in the longitudinal direction of the vehicle body and the flange width (length or protrusion amount) Wd: 12 mm, respectively. In this example, for the purpose of investigating the basic characteristics of the reinforcing material against bending, the reinforcing material was a straight member, and the lower ends were supported freely (pins) by a cylindrical support material having a span of 1100 mm. The length of the bumper reinforcement was a straight line of 1300 mm. As the bumper reinforcing material, a 7000 series aluminum alloy extruded shape material having an aging treatment of 0.2% proof stress of 435 MPa was used. In addition, as a comparative example, an example shown in FIG. 6 is shown in which the outer shape is the same, and the front wall and the upper and lower ends of the rear wall have a flange shape projecting in the vertical direction.

  FIG. 8 shows the load-displacement relationship of each bumper reinforcing material of the invention example and the comparative example. In addition, Table 1 shows the numerical values of the initial buckling load (kN), the energy absorption amount (kJ) when the displacement is 100 mm, and the maximum moment (kN · m) in each example in FIG.

  As apparent from Table 1 and FIG. 8, Invention Example 1 indicated by a thin solid line in FIG. 8 and Invention Example 2 indicated by a thick solid line are compared with Comparative Example 3 indicated by a thick dotted line in the initial compression load under the pole compression condition. (KN), the maximum bending moment (kN · m), which is an amount proportional to the initial maximum load, is substantially the same. However, since the decrease in load after the maximum load is suppressed, the inventive example can increase the amount of energy absorption (kJ) within a certain amount of displacement when the displacement is 100 mm. The tendency is particularly remarkable in the large invention example 2.

  In comparison between Invention Examples 1 and 2 and Comparative Example 3, Invention Example 1 is not as advantageous in energy absorption and initial buckling load as Comparative Example 3 as in Invention Example 2. However, the difference between Invention Examples 1 and 2 is only the difference in the depth (length l shown in FIG. 3) recessed toward the rear wall 2 side of the recess 10b formed by the bumper reinforcing material of FIGS. Thus, Invention Example 2 (FIG. 2) is larger than the recess 10a of FIG. 1 as described above. In this regard, the comparison between Invention Examples 1 and 2 and Comparative Example 3 shows that the amount of energy absorption and the initial buckling load differ depending on the depth (size) of the recess 10 provided. Therefore, Invention Example 1 shows a so-called lower limit in the case where the recess 10 is provided, and supports that it is necessary to select (design) the depth (size) of the recess 10 in order to obtain an optimum effect. . Therefore, the effects of the present invention and the significance of the configuration of the present invention are clear from the results of these examples.

  Further, in Table 1 and FIG. 8, Invention Example 4 indicated by a thick alternate long and short dash line in FIG. 8 is an example in which the thickness of the rear wall 2 is larger than the thickness of the front wall 1. By increasing the thickness of the rear wall 2, the load is particularly concentrated and easily cracked at the time of a pole collision. The strength and rigidity of the central part of the rear wall 2 are increased, making it difficult to break and ensuring the performance of the reinforcing material. can do. Depending on the conditions at the time of the pole collision, the central portion of the rear wall 2 may be cracked, and the performance of the reinforcing material may not be exhibited. However, the invention example 4 in which the thickness of the rear wall 2 is made thicker may cause such a situation. It can be prevented and the performance of the reinforcing material can be ensured.

  Further, in Invention Example 4, by increasing the thickness of the rear wall 2 by making the thickness of the rear wall 2 thinner by making the thickness of the rear wall 2 thinner, the thickness of the rear wall 2 is increased. As shown in the unit weights in Table 1, the weight is reduced by offsetting or minimizing. On the other hand, if the front wall 1 is not made as thin as the invention example 4, it is possible to increase the maximum load or to suppress a decrease in the load after the maximum load, and thus it is possible to increase the amount of energy absorption. Thus, in the present invention, by adjusting the thicknesses of the rear wall 2 and the front wall 1 to each other, the performance of the reinforcing material such as the maximum load and the energy absorption amount can be freely adjusted in relation to its weight. It also has an excellent effect that it can be designed.

  Further, FIG. 9 shows each flange width Wd (length or protrusion amount: horizontal axis, mm) and various performances (initial buckling load: left vertical axis, kN, energy at 100 mm displacement) in each example of Table 1 above. Absorption amount: right vertical axis, kJ). In the analysis conditions of FIG. 9, the cross-sectional dimensions of the reinforcing material in each example were the same as those in Table 1. However, only the flange width Wd of the bumper reinforcing material (described as the flange protrusion amount on the horizontal axis in FIG. 9) was 5 mm to 15 mm. (In Table 1, Wd is constant at 12 mm).

  In FIG. 9, the analysis results of Invention Examples 1 and 2 and Comparative Example 3 in which the length l of the recess 10 is changed are compared on the same graph. The initial buckling load on the left vertical axis is the invention example 1 in which the length l of the concave portion is small at any flange width Wd (projection amount) as shown in the lower three data indicated by the left-pointing left arrow. The white circles and dotted lines) are higher than the invention example 2 (black circles and solid lines) in which the length l of the recesses is large. On the other hand, the amount of EA on the right vertical axis, as shown in the upper three data indicated by the upper right arrow, on the contrary, the length of the recess is longer in Invention Example 2 (black square mark, solid line) where the length l of the recess is larger. The height l is higher than that of Invention Example 1 (white square mark, dotted line). However, the difference between the EA amounts tends to decrease as the flange width Wd of the horizontal axis increases, and from this point, the effect of increasing Wd can be seen.

  Further, as can be seen from FIG. 9, when Wd on the horizontal axis increases, the initial buckling load on the left vertical axis and the EA amount on the right vertical axis tend to increase in each example. However, when Wd is 12 mm or more, this increase rate decreases. That is, there is an optimum flange width (length or protrusion amount) Wd that can be expected to increase the load and increase the amount of EA. From the example of FIG. 9, the range of Wd from 12 mm to 15 mm is preferable, and the value Wd / Wb obtained by dividing this by the wall width Wb of the rear wall is about 0.08 to 0.1. It turns out that it is a range. In other words, the preferable ratio Wd / Wb is in the range of 0.08 to 0.1 when the length of the flange portion of the vehicle body reinforcing member is Wd and the wall width of the rear wall is Wb.

  According to the present invention, as a bending crushing characteristic, a bumper reinforcing material and a door guard bar having high bending strength and energy absorption characteristics with respect to a bending load at the time of a vehicle collision, and excellent in collision safety without separately providing a reinforcing material. It is possible to provide an automobile body reinforcing material made of aluminum alloy. For this reason, the use of an aluminum alloy material for automobile body reinforcement is greatly expanded, and the industrial value is great.

It is a perspective view which shows one embodiment of the bumper reinforcement material which concerns on this invention. It is a perspective view which shows the other embodiment of the bumper reinforcement material which concerns on this invention. It is sectional drawing (side view) which shows the reinforcement effect of the bumper reinforcement which concerns on this invention. It is a top view of the bumper reinforcement material of FIG. It is sectional drawing (side view) which shows the bumper reinforcement material of a comparative example. It is sectional drawing (side view) which shows the bumper reinforcement material of a comparative example. It is a top view which shows the deformation | transformation at the time of the pole collision of a bumper reinforcement material. It is explanatory drawing which shows the load-displacement relationship of the reinforcing material in an Example. It is explanatory drawing which shows the relationship between the flange width Wd and various performance in an Example.

Explanation of symbols

1: Front wall, 2: Rear wall, 3, 4: Side wall, 5: Intermediate wall, 6, 7, 8, 9: Flange, 10: Hollow part, 20: Bumper reinforcement, 30: Stay

Claims (2)

An automobile body reinforcing material having an excellent bending crushing characteristic, comprising an aluminum alloy hollow shape material having a substantially rectangular cross section, having the following configurations a to d, and having improved pole collision resistance .
a. The substantially rectangular cross section connects the front wall extending substantially in the vertical direction, the rear wall extending substantially in the vertical direction substantially parallel to the front wall and spaced apart, and the front wall and the rear wall, An approximately Japanese shape consisting of upper and lower lateral walls extending in a substantially horizontal direction at intervals, and intermediate walls extending in a substantially horizontal direction by connecting the central portions of these front and rear walls. It consists of a cross section.
b. The thickness of the front wall and the rear wall is 3 mm or more and 4.6 mm or less respectively , while the thickness of the upper and lower horizontal walls and the intermediate wall is thinner than the thickness of the front wall and the rear wall. And
c. The upper and lower lateral walls are connected to the front and rear walls by connecting the upper and lower portions of the front and rear walls, respectively, below or above the upper and lower ends of the front and rear walls. The wall and the rear wall are partitioned, and both end portions of the front wall and the rear wall are flange portions projecting in the vertical direction, the length of the flange portion is Wd, and the wall width of the rear wall is Wb The ratio Wd / Wb between the two is in the range of 0.08 to 0.1 .
d. The length of the intermediate wall on the front wall side is made shorter than the length of each of the upper and lower lateral walls, and the connection between the front wall side end of the intermediate wall and the front wall central portion is made to reduce the wall width of the front wall. In this manner, a concave portion extending in the longitudinal direction of the automobile body reinforcing material is formed in the central portion of the front wall.   The automobile body reinforcing material according to claim 1, wherein in the automobile body reinforcing material, the thickness of the rear wall is made larger than the thickness of the front wall.

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