JP4866394B2 - Aluminum alloy extruded hollow shape for energy protection member for personal protection - Google Patents

Description

The present invention has the function of protecting the pedestrian from the impact at the time of vehicle collision, it relates to personal protection energy-absorbing member for an aluminum alloy extruded hollow shape members.

  In recent years, bumpers of automobiles have been required to have a performance that protects the legs (lower limbs, hereinafter referred to as knees) of pedestrians, assuming that they collide with pedestrians. When protecting especially a leg part of such a pedestrian, the performance which a bumper absorbs the collision energy added by the pedestrian collision and protects a pedestrian's leg part is calculated | required.

  As means for this purpose, various ideas such as providing an impact absorbing device and an air bag under the bumper have been proposed. However, what is actually put into practical use is a relatively thick absorber (cushion material, energy absorbing member) such as foamed urethane or polystyrene foam on the front side of the bumper reinforcement body and on the back side of the bumper cover. It is only provided (for example, refer to the energy absorbing members of Patent Documents 1, 2, and 3).

Japanese Patent Laid-Open No. 2001-71837 (pages 1 and 2, Fig. 1) JP 2001-171448 A (1-2 pages, Fig. 1) JP 2000-52898 A (1-2 pages, Fig. 2)

  In addition, an occupant protection member called a knee protector or the like that protects the occupant's knees in the event of a vehicle collision is provided in the interior of the automobile. A conventionally proposed knee protector is made of a hollow aluminum alloy material, and is provided in front of a front seat in an automobile body to protect an occupant's knee in the event of a vehicle collision.

  These conventional knee protectors are made of an aluminum alloy hollow material having a substantially rhombic cross-sectional shape (or pantograph shape) (see Patent Documents 4 and 5). These substantially rhombic cross-sectional shapes constitute a fixed length partition wall (energy absorption part) that is easily plastically deformed sequentially when the occupant's knee collides.

U.S. Pat.No. 3,931,988 (1 page, Fig. 1) Japanese Patent Laid-Open No. 5-238338 (pages 1 and 2, Fig. 3)

First, with regard to pedestrian protection, there is a great limit to the amount of energy absorbed when the absorber (cushion material) collides with a pedestrian. That is, the distance (gap) between the front side of the vehicle body of the bumper reinforcement and the bumper cover is naturally limited in terms of vehicle body design, and the thickness of the absorber to be installed is inevitably limited. For this reason, in the absorber of the system which shrink | contracts in the thickness direction and absorbs the energy at the time of a collision with a pedestrian, there is a big limit in the energy absorption amount at the time of a collision.
Further, the density and rigidity of the absorber contracted in the thickness direction suddenly increases, and there is an area that functions as a rigid body. For this reason, when the thickness of the absorber is too small, the function as the rigid body occurs in a region where the amount of displacement is small. On the contrary, there is a possibility that a large reaction force is applied to the legs of the pedestrian.

  For this reason, with regard to pedestrian protection, the actual situation is that an appropriate means for absorbing collision energy in the event of a collision with a pedestrian has been sought in the bumper instead of or in combination with these absorbers. is there.

  This also applies to an occupant protection member called a knee protector that protects the occupant's knees in the event of a vehicle collision. In order to protect human knees from collision, including pedestrians and automobile occupants, with the personal protective member made of aluminum alloy hollow shape, the human protective member has an ideal load as shown by A in Fig. 1. It is necessary to show the displacement relationship (curve).

  In the ideal load-displacement relationship indicated by A in Fig. 1, first, the load does not rise significantly at the initial stage, but remains at the same load level. This indicates that the deformation of the hollow shape is started with a small collision load and without increasing the initial load (reaction force on the legs). In addition, the load-displacement relationship of A is constant even with the subsequent displacement (deformation), and there is no vertical fluctuation (small). This indicates that the deformation of the hollow shape member is continued in the displacement direction, the energy absorption is continued for a long time, and the reaction force to the leg portion does not increase over time. In such a load-displacement relationship of A, the amount of energy absorption increases.

  On the other hand, in the load-displacement relationship indicated by B in Fig. 1, as in the case of A above, deformation is started with a small impact load and without increasing the initial load (reaction force on the legs). The However, the load level decreases due to subsequent displacement (deformation). In addition, the load suddenly rises in a region where the amount of displacement is smaller than the ideal load-displacement relationship indicated by A in FIG. For this reason, it has shown that the load added to a pedestrian's leg part is also large. This example of B corresponds to the absorber in the above-mentioned bumper, and the density and rigidity of the absorber contracted in the thickness direction suddenly increases, and the region that functions as a rigid body arrives quickly. Suddenly stands up. In this case, the pedestrian's leg is greatly damaged.

  In addition, the load-displacement relationship indicated by C in FIG. This occurs because the rigidity and strength of the aluminum alloy hollow profile are too high. This indicates that the load at the beginning of the collision (reaction force to the leg) increases, and the damage to the leg increases.

  The load-displacement relationship indicated by D in Fig. 1 shows that although the initial load rise is small, the load level increases due to the subsequent displacement (deformation), and the reaction force on the legs gradually increases over time. It shows that. Even in this case, the damage to the leg portion is increased.

  The load-displacement relationship indicated by E in FIG. 1 is the same as the load-displacement relationship indicated by B above.

  However, for personal protection members made of aluminum alloy hollow shape members, the cross-sectional shape of the members and the tensile properties (tensile properties of the hollow shape material) that greatly affect the ideal load-displacement relationship (curve) indicated by A in Figure 1 above. The relationship between strength and strength is still unclear, including pedestrian protection and occupant protection.

  As described above, the relationship between the cross-sectional shape of the member and the tensile properties (tensile strength, proof stress) of the material hollow shape, which greatly affects the load-displacement relationship of the personal protection member, is not clear. For this reason, depending on these design conditions, the load-displacement relationship from B to E in Fig. 1 is often unavoidable, and the ideal load as a member for personal protection shown by A in Fig. 1- The displacement relationship (curve) is often not obtained. As a result, the actual situation is that the conventional personal protective members made of hollow aluminum alloy members have been manufactured through trial and error.

  Therefore, the object of the present invention is to provide a function for reliably protecting humans such as pedestrians and automobile occupants, to ensure the amount of energy absorption required in the case of a human leg collision, and only to load that does not cause damage. It is intended to provide an aluminum alloy extruded hollow member for a personal protection energy absorbing member that is compatible with not loading on the legs of the human body.

In order to achieve this object, the gist of the aluminum alloy extruded hollow shape member for the human protective energy absorbing member of the present invention is an aluminum alloy extruded hollow shape member that deforms in the cross-sectional direction and absorbs the human collision energy. It has a substantially rhombic cross-sectional shape with a wall thickness in the range of 0.3 to 10 mm, a 0.2% proof stress in the range of 30 to 300 MPa as a tensile property when used as a personal protection energy absorbing member, and a tensile strength of 0.2. % The difference in yield strength is 100 MPa or less, and the substantially rhombic cross section is provided with two flanges provided at intervals, and connecting between these flanges and curved outwardly, and provided at intervals. These flanges have projecting flanges that extend outwardly, and when the web receives a collision load from the flange side, each of the webs has an outer flange. It is intended to deform towards said Ri intersecting angle each 45 der within degrees between the inner surface and the outer surface of each web of each flange is positioned in front of Panpa reinforcement of the vehicle body In addition, in the rear surface side flange of the flange, it is supported from the back by the front side flange of the bumper reinforcement, and is joined to the front side flange of the bumper reinforcement at the portion of the overhanging flange of the rear surface side flange, Suppose that it is used as a member for pedestrian protection which absorbs the collision energy added to the bumper of a car by pedestrian collision .

  The aluminum alloy extruded hollow profile of the present invention (hereinafter also simply referred to as a hollow profile) has a significant influence on the load-displacement relationship of the personal protection member, and the tensile properties (tensile strength, Clarification of relationship with proof stress). As a result, a load-displacement relationship that approximates the ideal load-displacement relationship (curve) indicated by A in FIG. 1 is obtained as a personal protection energy absorbing member for protecting pedestrians and passengers. Therefore, it is possible to ensure both the amount of energy absorption necessary for a human leg collision and to load only a load that does not cause damage to the human leg. For this reason, it is attached to the front surface (collision surface) side of the bumper reinforcing material in the bumper as an interpersonal protection energy absorbing member for protecting the pedestrian, so that the pedestrian, particularly the knee, can be reliably protected. That is, the hollow profile of the present invention can be used as a means for absorbing collision energy in the event of a collision with a pedestrian, instead of the conventional absorber, or in combination with these absorbers.

  In the present invention, first, it is assumed that the shape of an aluminum alloy extruded hollow member is a substantially rhombic cross-sectional shape, which will be described later, for a personal protection energy absorbing member. In the present invention, it is assumed that the hollow shape member is deformed not in the longitudinal direction but in the cross-sectional direction to absorb the collision energy. That is, in order to achieve the ideal load-displacement relationship indicated by A in FIG. 1, first of all, with a small impact load, the initial load (reaction force to the leg) does not increase, In order to start the deformation of the hollow member, it is deformed in the cross-sectional direction so as to absorb the collision energy. If the cross-sectional shape other than this, for example, the aluminum alloy hollow shape is an ordinary substantially rectangular cross-sectional shape, the rigidity of the hollow shape is too high when the impact load is received from the flange side, and the cross-sectional direction is not deformed. It gives a great reaction force to the knee.

  Furthermore, as a premise, the aluminum alloy extruded hollow profile of the present invention has a wall thickness of 0.3 mm to 10 mm. When the wall thickness of the profile wall exceeds 10 mm, even if the strength of the hollow profile is reduced, the rigidity becomes too high and it becomes difficult to deform in the cross-sectional direction. In order to take advantage of the adoption of aluminum alloy hollow shape for weight reduction, the wall thickness of the shape wall should be relatively thin with 10mm or less. Since the aluminum alloy hollow profile of the present invention is newly added to the vehicle body as a personal protection energy absorbing member, the weight of the vehicle body including the fastening (fixing) means is newly increased even though it is light in itself. Therefore, when the wall thickness of the profile wall exceeds 10 mm, the effect of minimizing the weight increase due to the use of the aluminum alloy is reduced. In other words, even if the aluminum alloy hollow shape material of the present invention is thin with a thickness of 10 mm or less, there is an advantage that it is possible to enhance the impact absorbing effect at the time of a human collision. However, since it is necessary to ensure the minimum required rigidity as a personal protection energy absorbing member, the minimum wall thickness is 0.3 mm or more.

  Incidentally, even these knee protectors composed of aluminum alloy hollow shapes such as the conventional patent documents 4 and 5 are common in the deformation in the cross-sectional direction of the hollow shape, and the cross-sectional shape is also substantially rhombic cross-sectional shape as in the present invention. (Or pantograph shape). However, as described above, the relationship between the cross-sectional shape of the member and the tensile properties (tensile strength, proof stress) of the material hollow shape that greatly affects the load-displacement relationship of the personal protection member is not clear. For this reason, depending on the selection of the tensile characteristics of the aluminum alloy hollow profile, the absorption of collision energy due to deformation in the cross-sectional direction of the hollow profile after the initial stage is likely to fluctuate greatly, and the characteristics as a personal protection energy absorbing member are inferior. .

  That is, in the conventional patent documents 4, 5, etc., the load-displacement relationship shown by B and D in FIG. For example, in the load-displacement relationship shown by B, the load level is lowered by the subsequent displacement (deformation) in the cross-section direction of the hollow shape member. In addition, the actual stroke becomes smaller than the required stroke (displacement in the direction of the cross section of the hollow profile), and the load suddenly rises in a relatively small stroke area. For this reason, the load applied to the pedestrian's legs is larger than the ideal load-displacement relationship indicated by A in FIG.

  In addition, in the load-displacement relationship indicated by D, the load level increases due to the subsequent displacement in the cross-section direction of the hollow profile, and the reaction force on the legs gradually increases over time, causing damage to the legs. Becomes larger.

  In the present invention, in particular, in order to keep the load level due to the deformation in the cross-sectional direction of the hollow shape material after this initial stage, the aluminum alloy hollow shape material having a substantially rhombic cross-sectional shape at the time of use as a personal protection energy absorbing member. A major feature is to define tensile properties. In addition to this, in order to ensure that the deformation of the hollow shape starts with a small collision load and without increasing the initial load (reaction force to the legs), Specifies the tensile properties when used as a protective energy absorbing member.

  That is, in the present invention, as the tensile characteristics when using the aluminum alloy extruded hollow shape member having a substantially rhombic cross-sectional shape as a personal protection energy absorbing member, the 0.2% proof stress is in the range of 30 to 300 MPa, and the tensile strength The difference from the 0.2% proof stress is 100 MPa or less, preferably the difference between the tensile strength and the 0.2% proof stress is 70 MPa or less.

  In the present invention, the tensile property of the hollow shape member is defined as when used as a personal protection energy absorbing member until the aluminum alloy hollow shape material is manufactured by extrusion until it is used as a personal protection energy absorbing member. In addition, the tensile properties (mechanical properties) of the hollow profile may change. That is, depending on the type of the aluminum alloy, it is aged at room temperature during this time, or is attached to the vehicle body in advance depending on the automobile manufacturing process and undergoes a paint baking process (artificial age hardening process). In addition, when it is attached to the vehicle body later, it is replaced at the time of repair after a collision, or it is attached separately, it does not receive the paint baking process. Even if the tensile properties (mechanical properties) of the hollow profile change due to the history of these various uses, the tensile properties of the hollow profile during use as an actual personal protection energy absorbing member will be a problem. . Therefore, in this invention, the tensile characteristic of a hollow shape material is prescribed | regulated as the time of use as a personal protection energy absorption member.

  First, the significance of 0.2% proof stress among the tensile properties of aluminum alloy extruded hollow members will be described below. Even if the aluminum alloy extruded hollow member has a substantially rhombic cross-sectional shape, if the 0.2% proof stress exceeds 300 MPa, the rigidity of the hollow member becomes too high and deformation in the cross-sectional direction is difficult. For this reason, the load-displacement relationship indicated by C in FIG. 1 is established, and the load rises greatly in the initial stage. As a result, the load at the beginning of the collision (reaction force on the leg) increases, and the damage to the leg increases. Even if the displacement due to the deformation in the cross-section direction of the hollow shape progresses, there is a high possibility that the web breaks in particular. In this case, the load level decreases like the displacement after the initial stage of the load-displacement relationship indicated by E in FIG.

  On the other hand, when the 0.2% proof stress is less than 30 MPa, the load-displacement relationship indicated by B in FIG. 1 is obtained. In other words, although the deformation starts with a small collision load and the initial load (reaction force on the legs) does not increase, the load suddenly rises in a region with a small amount of displacement. A large reaction force is applied to the legs. Accordingly, the 0.2% proof stress of the aluminum alloy hollow profile is set in the range of 0.2 to 300 MPa.

  Next, the significance of the difference between the tensile strength and the 0.2% proof stress of the tensile properties of the aluminum alloy extruded hollow member will be described below. The smaller the difference between this tensile strength and 0.2% proof stress, the closer to the ideal load-displacement relationship shown by A in Fig. 1, and the load level can be kept constant during the displacement (deformation) after the initial load. it can. This is because the smaller the difference between the tensile strength and 0.2% proof stress of the hollow shape material, the smaller the work hardening associated with the increase in strain, even when strain due to interpersonal impact load enters the hollow shape material, and plastic deformation (cross-sectional direction) It is assumed that this is due to the progress of deformation in the width direction.

  On the other hand, when the difference between the tensile strength and 0.2% proof stress exceeds 100 MPa, strictly 70 MPa, the load level depends on the subsequent displacement (deformation) in the ideal load-displacement relationship indicated by A in Fig. 1 above. Cannot be kept constant. In other words, the load-displacement relationship indicated by D in Fig. 1 is reached, the load level increases with subsequent displacement (deformation), and the reaction force on the legs gradually increases over time, resulting in significant damage to the legs. To do. This is because the greater the difference between the tensile strength and 0.2% proof stress of the hollow shape, the more the strain caused by interpersonal collision load enters the hollow shape, the more the work hardens due to the increase in strain and the plastic deformation (deformation in the cross-sectional direction). This is probably because the load required for Therefore, the difference between the tensile strength and 0.2% proof stress of the extruded aluminum alloy is 100 MPa or less, preferably 70 MPa or less.

  By adopting the cross-sectional shape and tensile properties as in the present invention, the aluminum alloy extruded hollow shape can be approximated to the ideal load-displacement relationship indicated by A in FIG. That is, the energy absorbing member can reduce the maximum load in the load displacement when assuming an interpersonal collision, and can cause a deformation in the cross-sectional direction necessary for energy absorption with a low collision load commensurate with the interpersonal collision. .

  In addition, even if the displacement of the hollow profile progresses due to the deformation in the cross-sectional direction, there is no breakage of the web in particular, the load reduction amount is extremely small, energy absorption is performed continuously, and the amount of energy absorption necessary for personal protection Can be secured.

  Furthermore, all of these hollow members (personal protection energy absorbing members) operate at a level far lower than the crushing strength and rigidity of the automobile member (vehicle body) to which this energy absorbing member is attached or supported. Is called. For this reason, there is no influence on the automobile member itself to which the energy absorbing member is attached during the operation of these personal protection energy absorbing members. The member to which this energy absorbing member is attached or supported is a bumper reinforcement for pedestrian protection and a pole-shaped instrument panel reinforcement for occupant protection. Therefore, for example, even when the bumper is repaired after a pedestrian collision, there is no need to replace the bumper reinforcing material or the stay, and only the added energy absorbing member needs to be replaced, which is very economical. This is also the case for occupant protection, and even when the knee protector is repaired after the occupant's knee collides, there is no need to replace the instrument panel reinforcing member or the like, and only the added knee protector can be replaced.

  Hereinafter, a preferred embodiment of the substantially rhombic cross-sectional shape of the aluminum alloy extruded hollow member of the present invention will be described. 2 and 3 are plan views showing preferred embodiments of various substantially rhombus cross-sectional shapes of the aluminum alloy extruded hollow member of the present invention.

  First, the cross-sectional structures (shapes) of the aluminum alloy extruded hollow members 1a and 1b of the present invention shown in FIGS. 2 (a) and 2 (b) are basically provided at intervals substantially parallel to each other in the vertical direction of the drawings. The two flanges 2 and 3 and the two left and right webs 4 and 4 provided at an interval connecting the flanges are integrally formed. The straight flanges (vertical wall portions) 2 and 3 are arranged in parallel in the vertical direction of the figure, and these flanges intersect these flanges at a certain angle θ1, θ2, θ3, and θ4. In this form, left and right webs 4, 4 arranged at intervals in the left-right direction (for example, the vehicle body width direction) in the figure intersect to connect the flanges. The flanges 2 and 3 have projecting flanges 2a and 2b and projecting flanges 3a and 3b, respectively, projecting outward in the left-right direction (for example, the vehicle body width direction) in the figure.

  The hollow profile 1a in FIG. 2 (a) and the hollow profile 1b in FIG. 2 (b) are basically similar, but the spacing between the flanges 2 and 3 is different, and the hollow profile 1a is more The interval is longer than that of the hollow shape member 1b. In this regard, the hollow shape 1a having a larger ratio H / B between the distance H between the flanges and the length B of both flanges has a higher crushing strength than the hollow shape 1b having a smaller H / B. It becomes low and easily deforms in the cross-sectional direction.

  The aluminum alloy extruded hollow members 1a and 1b of the present invention, including the hollow members described later, are deformed in the cross-sectional direction (vertical direction in the figure) with respect to the direction of the interpersonal collision load F shown in the figure. Arranged with respect to the vehicle body. For example, when it is attached to the front surface of a bumper reinforcement for a pedestrian protection member, the vertical direction in the figure is the vehicle longitudinal direction (vehicle longitudinal direction).

  Here, each of the webs 4, 4 is curved in an arc shape toward the outer side in the left-right direction in the figure, and is further convex at the substantially central portion of each of the webs 4, 4. Overhanging bent portions 5 and 5 are formed. Due to these requirements, the aluminum alloy extruded hollow members 1a and 1b in FIGS. 1 and 2 have a substantially rhombus shape. In the present invention, the arc-shaped bending direction of each of the webs 4 and 4 is outward, but this means that the webs 4 and 4 face outward rather than inward of each other. In the case of a pedestrian protection member described later, the bending direction with respect to the vehicle body also depends on the attachment method, and in the case of an aspect as a pedestrian protection member described later, the outer side is the vertical direction of the vehicle body in FIG. Is the width direction of the car body.

  When a load due to interpersonal collision is applied from the arrow F indicating the load direction due to the synergistic action of the outwardly curved arcs (bulges) of the webs 4 and 4 and the bent portions 5 and 5 of the substantially central portion, As shown in FIGS. 9 and 10, which will be described later, the webs 4 and 4 spread outwardly around the bent portions 5 and 5 as shown in FIGS. 9 and 10 to be described later, and the front side flange 2 against the load has a rear surface. As it approaches the side flange 3 side, it is transformed into a pantograph shape of a train in the cross-sectional direction. The bent portions 5 and 5 at the substantially central portions of the webs 4 and 4 promote such a function and exhibit a synergistic action with the arc-shaped curve, so that the personal protection is more required. It is preferable to provide it.

  For example, if the webs 4 and 4 have a straight, substantially rectangular cross-sectional shape, there is no bending due to interpersonal collisions such as pedestrians even within the tensile property range of the hollow profile of the present invention. A large load is required at the start of deformation, the above-described action of the present invention does not occur, and it cannot be an energy absorbing member for personal protection. In addition, if the webs 4 and 4 have a shape such as an arc that is recessed inward, the webs 4 and 4 come into contact with each other during the deformation and the load increases, and thus the above-described action of the present invention does not occur. It cannot be an energy absorbing member for personal protection.

  FIG. 9 shows the FEM analysis results of the time-dependent changes in the load deformation state of the aluminum alloy extruded hollow profile 1a of the present invention and FIG. 10 for the aluminum alloy extruded hollow profile 1b of the present invention for each displacement of 5 mm. The deformation state changes in the order of (a) to (h) in these figures. For example, when a load due to an interpersonal collision is applied to an aluminum alloy extruded hollow shape (for example, from the upper side of the figure), each of the webs 4 and 4 becomes (bent portions 5 and 5 due to the arc-shaped bending action of the webs 4 and 4. If it has, the front flange 2 is deformed so that it spreads outward (with the bent portions 5 and 5 as the center) and the front flange 2 approaches the rear flange 3 side. Further, even if the displacement due to the deformation in the cross-sectional direction advances, the web does not break or the like and deforms in the cross-sectional direction. This effect is remarkable when the bent portions 5 and 5 are formed. As a result, the ideal load-displacement curve shown by A in FIG. 1 is obtained.

  Next, FIGS. 3 (a), (b), and (c) show another embodiment of the substantially rhombic cross-sectional shape of the extruded aluminum alloy of the present invention. The sectional shape of the hollow profile in FIGS. 3 (a), (b), and (c) is basically the same as the sectional profile of the hollow profile in FIG. However, the substantially central portion of each web of the hollow shape member 1c in FIG. 3 (a) is more convex outward than the bent portion 5 of the aluminum alloy extruded hollow shape members 1a and 1b in FIG. An overhanging bent portion 5 is formed. Therefore, the cross-sectional shape is easily deformed in the cross-sectional direction with a smaller collision load.

  In the aluminum alloy extruded hollow members 1d and 1e shown in FIGS. 3 (b) and 3 (c), the distance between the webs is larger than that of the hollow member 1c. Further, with respect to the bent portion 5, the hollow shape member 1d of FIG. 3 (b) has a smaller overhang than the bent portion 5 of the hollow shape members 1a and 1b of FIG. Further, in the hollow shape member 1e of FIG. 3 (c), the bent portion 5 is not formed at the substantially central portion of each web. Therefore, the cross-sectional shape is less likely to deform in the cross-sectional direction than the hollow shape member 1c in FIG. 3 (a) and the hollow shape members 1a and 1b in FIG. Note that the deformation of each of the curved webs 4 and 4 when a load due to an interpersonal collision is applied from the arrow F indicating the load direction causes the hollow profile 1a, 1b in FIG. 2 or the hollow profile 1c in FIG. Like (commonly), it is deformed in the cross-sectional direction (vertical direction in the figure) so as to spread outward (in the horizontal direction in the figure).

  Here, the arc-shaped curvature of each of the webs 4 and 4 of each hollow profile of the present invention ensures that the cross-sectional deformation spreads outward, so that the front flange inner surface 2c and the left and right web outer surfaces 4a The angles θ1 and θ2 that intersect with each other, and preferably the angles θ3 and θ4 that intersect the rear flange inner surface 3c and the left and right web outer surfaces 4a are within 45 degrees. In all of the aluminum alloy extruded hollow members shown in FIGS. 2 to 5, the angles θ1 to θ4 are within 45 degrees. By adjusting these web angles θ1, θ2, θ3, and θ4, it is possible to control the maximum load and the amount of load decrease in the load displacement of the aluminum alloy extruded hollow member. When the intersecting angles θ1, θ2, θ3, θ4 exceed 45 degrees, even if the hollow profile of the present invention is within the tensile property range, the load load during human collision (biased with respect to the front flange 2) Depending on the load, etc., it tends to break during deformation. When this rupture phenomenon occurs, load reduction occurs, and it becomes difficult to secure an energy absorption amount necessary for personal protection.

  Furthermore, in each of the hollow shape members of the present invention, the flanges 2 and 3 are extended outward (toward the left and right directions in the figure, for example, in the vehicle body width direction), and are extended flanges 2a, 2b and 3a, 3b respectively. The overhanging flanges 2a, 2b and 3a, 3b may be provided on either one of the flanges. The overhanging flanges 2a, 2b and 3a, 3b have the advantages described below.

  By having the overhanging flanges 2a, 2b and 3a, 3b, the flanges 2 and 3 can respond to an interpersonal collision with a sufficient wall area (collision area). In other words, even when an impact is applied to the front flange 2 from the direction F due to an interpersonal collision, the maximum load in load displacement is low, but the bending rigidity of the front flange 2 is increased, preventing crushing or damage. preferable. Further, even if the collision position of the person (eg, knee) is different, or even if the position of the person collision is shifted from the flange center point, it is preferable in terms of energy absorption.

  In addition, these overhanging flanges 2a, 2b and 3a, 3b, as will be described later, can easily perform mechanical joining such as welding or bolts with a member supporting the extruded aluminum alloy of the present invention. From the viewpoint of workability and joining workability. Note that the flanges 2 and 3 are not necessarily linear, but may be curved such as arcs that swell outward or inward. In addition, unevenness may be provided even if the surface is not flat. Therefore, it is allowed to appropriately change the shape of the hollow shape material in accordance with the use conditions while having the above basic requirements.

  In the present invention, the deformation characteristics in the cross-sectional direction of these substantially rhombic cross-sectional shapes and the tensile characteristics (0.2% proof stress, difference between tensile strength and 0.2% proof stress) of the extruded aluminum alloy are the maximum allowable in each application. Considering the load (initial load) and the required energy absorption, the approximate rhombus cross-sectional shape and tensile properties are selected as appropriate. In other words, by selecting the cross-sectional shape and the tensile characteristics of the hollow shape member, it is possible to freely control and select the maximum load and the amount of energy absorption in the load displacement according to the use of the personal protection member.

  And if it is an embodiment of the hollow profile of the present invention having a substantially rhombic cross-sectional shape as described above, the aluminum alloy extruded hollow profile, together with the tensile properties at the time of use as a personal protection energy absorbing member, The maximum load or maximum acceleration in the load displacement or acceleration displacement can be surely lowered, and the deformation in the cross-sectional direction necessary for energy absorption can be generated with an appropriate collision load commensurate with a human collision such as a pedestrian. In addition, when the aluminum alloy extruded hollow shape is used as a personal protective energy absorbing member, even when displacement due to deformation in the cross-sectional direction progresses, the web does not break in particular, and the load fluctuation is extremely high. A small and constant load level can be reliably maintained and the deformation stroke is extended, so that energy is continuously absorbed, and the amount of energy absorption and deformation (displacement) necessary to protect people such as pedestrians are ensured. Can be secured.

  Hereinafter, an embodiment in which the hollow profile 1a of the present invention shown in FIG. 2 (a) is attached to a bumper reinforcement for protecting a pedestrian and attached to a vehicle body bumper will be described with reference to FIGS. FIG. 4 is a partial cross-sectional side view of the entire vehicle body bumper, and FIG. 5 is a plan view showing the main parts of the vehicle bumper, such as a bumper reinforcement.

  In FIG. 4, first, 10 is a bumper cover, 9 is an absorber, 1a is an extruded hollow aluminum alloy material of the present invention, 6 is a bumper reinforcement, 7 is a stay, 8 is a vehicle body side member, and these are in the vehicle longitudinal direction. They are arranged or joined in order. The absorber 9 is appropriately composed of a commercially available material such as foamed urethane or polystyrene, but as described above, in the present invention, the thickness of the absorber 9 can be made thinner or smaller than that of the prior art. Further, it is possible to use no absorber 9 for pedestrian protection.

  4 and 5, two aluminum alloy extruded hollow members 1a are arranged as energy absorbing members on the front surface of the bumper reinforcing member 6 at intervals. However, in each of the webs 4 and 4 of the hollow shape member 1a in FIG. 4, the arcuate bending direction is the outer side in the vertical direction of the vehicle body. Further, in each of the webs 4 and 4 of the hollow shape member 1a in FIG. 5, the arcuate bending direction is the outer side in the width direction of the vehicle body. The effect does not change in any direction or slightly deviating from these directions. In addition, the number and position of the hollow shape members arranged on the front surface of the bumper reinforcing material as the energy absorbing member are appropriately determined according to the bumper design conditions and pedestrian protection conditions. In this regard, the hollow shape member 1a has the overhanging flanges 2a, 2b and 3a, 3b as described above, so that even if the pedestrian collision position is different, or the pedestrian collision position is the center of the flange Even if it deviates from the point, there is an advantage that energy can be absorbed similarly. For this reason, the number and position of the arrangement can be determined according to the bumper design conditions and pedestrian protection conditions, and the bumper design conditions and pedestrian protection conditions are not subject to restrictions from the hollow shape (energy absorbing member) side. There is no advantage.

  4 and 5, both of the aluminum alloy extruded hollow members 1a are supported from the back side by the front side flange 11 (flange surface 11a) of the bumper reinforcement 6 at the rear side flange 3 and the rear side flange. The three overhanging flanges 3a and 3b are mechanically joined to the front flange 11 of the bumper reinforcement 6 by bolts 19. This joining method may be welding or a combination of welding and mechanical joining.

  In FIGS. 4 and 5, the bumper reinforcing material 6 made of a hollow material is supported by two hollow cylindrical stays 7 on the back surface thereof. Further, it is joined to the vehicle body side member 8 via the stay 7 and supported on the vehicle body side. Specifically, the front flange 16 on the stay 7 side and the rear flange 12 on the bumper reinforcement 6 are connected to the rear flange 17 on the stay 7 side and the front flange 18 on the side member 8 by bolts 19, respectively. It is joined. This joining method may also be welding or a combination of welding and mechanical joining.

  As the bumper reinforcing material itself in this embodiment, a hollow shape made of aluminum alloy or steel can be used. Furthermore, the longitudinal shape of the bumper reinforcement can be freely selected from the viewpoint of the vehicle body design. In addition to the above-mentioned linear shape, it may have linear or curved curved portions (bent portions) at both ends. The whole may be curved. Bumper reinforcement (hollow profile) The cross-sectional shape and structure of the bumper itself absorbs the energy of external forces applied from the front and rear of the vehicle body or by collisions in the front and rear, by its own bending deformation and cross-sectional deformation. Therefore, it is comprised by the substantially rectangular cross-section hollow shape material. Specifically, as shown in FIG. 4, a front wall (front side flange) 11 erected in the collision direction or the longitudinal direction of the vehicle body, a rear wall (rear side flange) 12 positioned rearward, and The side walls (webs) 13 and 14 connected at right angles form a substantially rectangular cross section.

  Furthermore, in the bumper reinforcing member 6 of FIG. 4, the side walls 13 and 14 are formed so that the cross section has a cricoid shape in order to increase the crushing strength, and two hollow section sections are provided in the substantially rectangular hollow cross section. A horizontal intermediate wall (medium rib) 15 is provided in parallel with the horizontal wall 15. The cross-sectional shape and structure of these bumper reinforcements (hollow shape members) depends on the size (height) of the bumper reinforcement cross-section according to the vehicle body design and the required characteristics such as the strength or impact energy absorption. In addition to the cross-section, these are appropriately selected from a mouth shape without the middle ribs, an eye shape with two middle ribs, and a rice field with the vertical and horizontal middle ribs crossed.

  Next, since the stay 7 in FIG. 4 is joined to the bumper reinforcing material, the stay 7 is a front wall according to the back surface shape of the bumper reinforcing material such as a straight line, a curved line, or an inclined shape. In order to reduce the weight of the stay, it is preferable that the stay itself is also a hollow cylinder or shape. And about a material and a manufacturing method, as with a bumper reinforcement material, steel plates, such as normal steel and high tension, an aluminum alloy extrusion shape material, a board | plate material, etc. are selected suitably.

Next, an embodiment in which the aluminum alloy extruded hollow member of the present invention is used as an energy absorbing member for personal protection as a passenger protecting member such as a knee protector for protecting a passenger's knee at the time of a vehicle collision is outside the scope of the present invention. Will be described with reference to FIGS. FIGS. 6 and 7 are front views of the occupant protection member obtained by connecting the extruded aluminum alloy hollow members of the present invention. FIG. 8 is a front view showing an embodiment in which the occupant protection member 20a of FIG. 6 (a) is attached to a vehicle body member.

  Each of the occupant protection members 20a to 20d in FIGS. 6 and 7 is configured by selectively combining the aluminum alloy extruded hollow shapes 1a to 1d described with reference to FIGS. That is, these selected hollow members are connected to each other in the width direction (cross-sectional direction), and a plurality of the two hollow shape members are connected to each other to form an energy absorbing portion (partition wall) continuous in the width direction (cross-sectional direction) of the hollow shape member. It is composed. 6 and 7, the right side of each figure is assumed to be the occupant's knee side, and the left side of the figure is assumed to be the front side of the vehicle body.

  The number of these hollow members to be connected is as an occupant protection member, in order to ensure the amount of impact energy absorbed by continuous plastic deformation in the cross-sectional direction, and to be attached to the vehicle body member at the optimum position relative to the knee. To do this, the required length (stroke) is selected and determined. Even if the number of connections is excessively large, the number of steps for bonding to each other increases, and the bonding strength may decrease. Therefore, it is not necessary to increase the number of connected hollow profiles even if the installation space of the vehicle body is limited. There is also a method of reducing the number of connections by increasing the width of the hollow member (the length of the web). However, when the angle θ1, θ2, θ3, and θ4 at which the inner surface of the flange 2 intersects with the outer surface of the web exceeds 45 degrees by increasing the length of the web), as described above, the tensile characteristics of the hollow profile of the present invention Even within the range, depending on the state of the load applied at the time of the person-to-person collision, the web is likely to break during deformation. In this respect, the preferred number of connected hollow shapes is about 2 to 4.

  An occupant protection member 20a shown in FIG. 6 (a) is a combination of two hollow profiles 1a of the present invention shown in FIG. 2 (a). That is, these hollow members 1a are joined to each other at flanges 3 and 2 and overhanging flanges 3a and 2a provided on these flanges, and are connected to each other in the width direction (in the cross-sectional direction) of the hollow members. . This is basically the same for the modes of FIGS. 6 (b), 7 (a), and (b).

  The passenger protecting member 20b in FIG. 6 (b) includes the hollow profile 1a of the present invention shown in FIG. 2 (a) and the hollow profile 1b of the present invention shown in FIG. Are combined in the same manner as in FIG. 6 (a).

  The occupant protection member 20c in FIG. 7 (a) is connected in the same manner as in FIG. 6 (a) by combining three hollow members 1a of the present invention shown in FIG. 2 (a). The occupant protection member 20d in FIG. 7 (b) includes two hollow profile members 1a of the present invention shown in FIG. 2 (a) and the occupant's knee side (on the right side of the figure). The hollow shape members 1b1 of the present invention shown in FIG. 6) are combined and connected in the same manner as in FIG. 6 (a).

  In the aspect of the occupant protection member that connects the extruded aluminum profiles of the present invention described above, the length (stroke) of the energy absorbing portion described above is increased or decreased as necessary depending on the number of the hollow profiles to be connected. Can also be adjusted. For this reason, it can be applied to a member for protecting an occupant corresponding to many various vehicle types having different conditions.

  As a joining means for connecting these hollow members to each other at their flanges and / or overhanging flanges, a mechanical joint such as an adhesive or a bolt, welding, a combination thereof, or the like is appropriately selected. In other words, according to the present invention, an aluminum alloy extruded hollow member can be connected by bonding with an adhesive without increasing the bonding strength using relatively complicated bonding means such as mechanical bonding such as bolts or welding. There is also an advantage that the joining strength that can satisfy the function as a member for protecting the passenger is ensured.

  FIG. 8 shows an aspect in which the occupant protection member 20a of FIG. 6 (a) is attached to a vehicle body member. In FIG. 8, the occupant protection member 20a is disposed in front of the knee 24 so as to face the position of the occupant's knee 24 from obliquely upward to downward. This arrangement position is variously selected or determined according to the vehicle type and the vehicle body design. For example, it may be disposed in front of the knee 24 so as to face the position of the occupant's knee 24 in the horizontal direction. The occupant protection member 20a is joined directly or through a bracket 21 or the like to a pole-shaped instrument panel reinforcing member 22 or the like that is connected at both ends to pillars provided on both sides of a vehicle body member (not shown). The bracket 21 includes an arm 21a for joining to the instrument panel reinforcing member 22 and a flange 21b for joining to the flanges 2a and 2b which are rear surfaces of the passenger protecting member 20a.

  On the other hand, the front flange (collision surface) side flanges 3a and 3b on the occupant's knee 24 side are provided with softness and the like so that the protection of the occupant's knee 24 and the above-described collision position of the occupant's knee can be accommodated. A knee panel (a knee protection panel) 23 and the like that are selectively formed from materials and extend corresponding to the occupant's knee 24 surface are selectively provided. For joining these members, an adhesive, mechanical joining, welding, a combination thereof, or the like is appropriately selected.

  Here, FIGS. 11 and 12 show the time-dependent changes in the load deformation state of the occupant protection member in which the extruded aluminum alloy profiles of the present invention are connected to each other as FEM analysis results. FIGS. 11 (a), 11 (b), and 11 (c) show changes over time in the load deformation state for each displacement of 20 mm, 40 mm, and 60 mm in the load displacement curve of the occupant protection member 20a of the present invention in FIG. FIGS. 12 (a), 12 (b) and 12 (c) show changes over time in the load deformation state for every displacement of 20 mm, 30 mm and 40 mm in the load displacement curve of the occupant protection member 1b of the present invention in FIG.

  As can be seen from FIGS. 11 (a), (b), and (c), the same aluminum alloy extruded hollow member 1b in the occupant protection member 20a is curved in the arcuate shape of the web 4 when a load due to collision is applied. As a result, the webs 4 and 4 are plastically deformed so as to spread outwardly around the bent portions 5 and 5 and so that the flanges 2 and 3 approach each other. At that time, if the aluminum alloy extruded hollow members 1a have the same cross-sectional shape, such plastic deformation (deformation in the cross-sectional direction) must be simultaneously and evenly deformed despite being connected. I understand.

  On the other hand, in the occupant protection member 20b of the present invention, which is a combination of aluminum alloy extruded hollow members 1a and 1b having different cross-sectional shapes, as shown in FIGS. 12 (a), (b), and (c), the load caused by the collision When applied, the hollow members do not plastically deform simultaneously and evenly. That is, the ratio H / B between the distance H between the flanges and the length B of both flanges is large and the hollow shape 1a having a lower crushing strength is deformed first, and then this H / B is smaller and the crushing strength is lower. It can be seen that the high hollow profile 1b is deformed.

  As described above, according to the present invention, the energy absorption performance of the occupant protection member can be freely adjusted by adjusting and selecting the cross-sectional shape of the hollow shape material combined with the adjustment of the length of the hollow shape material (energy absorption portion). Can control and design.

  As an aluminum alloy that satisfies these required characteristics, general-purpose (standard) aluminum such as 3000 series, 5000 series, 6000 series, 7000 series, etc. stipulated in AA to JIS standards, which are generally used for such structural member applications An alloy material (extruded profile) that has been tempered or heat-treated so as to have the above-described tensile properties of the present invention, such as O 2, T4, T6, T7, etc., is preferably and selectively used. Among them, aluminum alloys such as 5000 series and 6000 series having good formability and relatively high yield strength are preferable. The aluminum alloy hollow shape of the present invention uses a hollow shape produced by a conventional method of hot extrusion.

  The aluminum alloy extruded hollow shapes 1a and 1b shown in FIGS. 2 (a) and 2 (b), respectively, were subjected to a crushing test by changing the tensile properties depending on the type of alloy and tempering (heat treatment). The load-displacement relationship was determined. These results are shown in FIG. 13 (a), (b), FIG. 14 (a), and (b), respectively.

  The crushing test conditions were the following common conditions in both the above invention examples and comparative examples. That is, the load of the load is indicated by F in FIG. 2 by the press test device on the hollow shape members 1a and 1b placed on the base with the cross-section direction of the hollow shape as the vertical direction (just in the vertical direction in FIG. 2). The load was applied to the center of the flange 2 in each hollow profile 1a, 1b.

  Each aluminum alloy ingot, which is a composition component of 6063, 6N01, 3004 according to JIS standard, was hot-extruded after homogenization heat treatment to form hollow shapes 1a, 1b having a wall thickness of 4.0 mm. These hollow shapes were subjected to tempering treatment such as O 2 and T6 to adjust the tensile properties of 0.2% proof stress and the difference between tensile strength and 0.2% proof strength. These conditions, tensile properties, and cross-sectional shapes are organized and shown in Table 1.

The outer dimensions of the hollow sections 1a and 1b are 40 mm for the length B of both flanges 2 and 3, and the distance H between the flanges 2 and 3 is 40 mm for 1a, 30 mm for 1b, and the distance between the flanges of the webs 4 1a is 5 mm, 1b is 10 mm, the web 4 is projected to the right and left as 17.5 mm, 1b is 15 mm, and the web angles θ1, θ2, θ3, and θ4 are equally 45 degrees.

  The aluminum alloy extruded hollow shape material 1a of the present invention shown in FIGS. 13 (a) and 13 (b) has a substantially rhombic cross-sectional shape as shown in FIG. 2 (a). As the tensile properties, the 0.2% proof stress is in the range of 30 to 300 MPa, and the difference between the tensile strength and the 0.2% proof stress is 100 MPa or less. For this reason, as shown by solid lines in FIGS. 13 (a) and 13 (b), each approximates an ideal load-displacement relationship (as shown in FIG. 1) indicated by a dotted line A.

  That is, the load does not rise significantly at the initial stage, and the load level remains unchanged. This indicates that the deformation of the hollow shape is started with a small collision load and without increasing the initial load (reaction force on the legs). Also, the load level is constant due to the subsequent displacement (deformation), and the vertical fluctuation is small. Therefore, the deformation of the hollow shape member is continued in the displacement direction, the energy absorption is continued for a long time, and the reaction force to the leg does not increase even with the passage of time. In addition, this load-displacement relationship also increases energy absorption.

  However, the difference between the tensile strength and 0.2% proof stress of 6063-T6 tempered material in Fig. 13 (b), where the difference between the tensile strength and 0.2% proof stress is smaller, is greater than 90 MPa. Compared to the 6063-O tempered material in Fig. 1, it approximates the ideal load-displacement relationship shown in Fig. 1 indicated by the dotted line A. The 6063-O tempered material in Fig. 13 (a), which has a larger difference between tensile strength and 0.2% proof stress, gradually increases its load compared to the ideal load-displacement relationship indicated by dotted line A. .

  On the other hand, the 3004-O material of the comparative example indicated by the alternate long and short dash line in FIGS. 14 (a) and 14 (b) has a difference between the tensile strength and the 0.2% proof stress of 110 MPa as shown in Table 1, and the upper limit of 100 MPa. It is over. Therefore, as shown in FIG. 2 (a), it is a hollow section 1a having a substantially rhombic cross-sectional shape, and the ideal load indicated by the dotted line A is in spite of the fact that the 0.2% proof stress is within the scope of the invention of 70 MPa. -Compared to the displacement relationship, the load due to displacement is increasing. That is, it can be seen from these results that the load tends to increase as the difference between the tensile strength and the 0.2% proof stress increases. Therefore, it is understood that there is a critical point of load increase where the difference between the tensile strength and the 0.2% proof stress is allowable around 100 MPa, assuming a substantially rhombic cross-sectional shape.

  Furthermore, the 6N01-T6 material indicated by the solid lines in FIGS. 14 (a) and 14 (b) has a difference between the tensile strength and the 0.2% yield strength of 30 MPa and within the invention range of 100 MPa or less, but the 0.2% yield strength is 255 MPa. And relatively high. For this reason, the initial maximum load has risen relatively large compared to the 6063 material of FIG. This tendency becomes more prominent as the 0.2% yield strength is higher. Therefore, it is understood that the 0.2% proof stress of the hollow profile has an upper limit around 300 MPa, assuming a substantially rhombic cross-sectional shape.

  According to the present invention, an aluminum alloy extruded hollow member for a human protective energy absorbing member having a function of reliably protecting a human such as a pedestrian or an automobile occupant, and a human protective energy absorbing member comprising the aluminum alloy extruded hollow member. Can be provided. In other words, it is possible to ensure both the amount of energy absorption necessary for a human leg collision and that only a load that does not cause damage is applied to the human leg. Therefore, the present invention greatly expands the use of the aluminum alloy material for the energy absorbing member, and has a great industrial value.

It is explanatory drawing which shows the ideal load-displacement relationship of an energy absorption member. It is a top view which shows one embodiment of this invention. It is a top view which shows one embodiment of this invention. It is a partial cross section side view of the whole vehicle body bumper which shows the usage example to the pedestrian protection member of this invention. It is a top view which shows principal parts, such as a bumper reinforcement, among the vehicle body bumpers of FIG. It is a front view which shows the usage example to the member for occupant protection of this invention. It is a front view which shows the usage example to the member for occupant protection of this invention. It is a side view of a passenger protection member showing an example of use for a passenger protection member of the present invention. It is explanatory drawing which shows the time-dependent change of the load deformation state of this invention. It is explanatory drawing which shows the time-dependent change of the load deformation state of this invention. It is explanatory drawing which shows the time-dependent change of the load deformation state of this invention. It is explanatory drawing which shows the time-dependent change of the load deformation state of this invention. It is explanatory drawing which shows the load-displacement relationship of an aluminum alloy hollow shape material. It is explanatory drawing which shows the load-displacement relationship of an aluminum alloy hollow shape material.

Explanation of symbols

1: Aluminum alloy extruded hollow shape, 2: Front flange, 3: Rear flange, 4: Web,
5: Overhang, 6: Bumper reinforcement, 7: Stay, 8: Side member, 9: Absorber,
10: Bumper cover, 11: Front flange, 12: Rear flange, 13, 14: Web, 15: Medium rib, 16, 17, 18: Flange, 19: Bolt, 20: Crew protection member,
21: Bracket, 22: Instrument panel reinforcement, 23: Knee panel, 24: Crew knee,

Claims (2)

An aluminum alloy extruded hollow shape that deforms in the cross-sectional direction and absorbs human collision energy, and has a substantially rhombic cross-sectional shape with a wall thickness of 0.3 to 10 mm as a human protective energy absorbing member As the tensile properties when using the two, the 0.2% proof stress is in the range of 30 to 300 MPa, the difference between the tensile strength and the 0.2% proof stress is 100 MPa or less, and the substantially rhombic cross section is provided with two gaps The flanges are composed of two webs connected between the flanges and curved outwardly, and spaced apart from each other, and these flanges have projecting flanges facing outwards. When receiving a collision load from the flange side, each of the webs is deformed outward, and an angle at which the inner surface of each flange intersects the outer surface of each web Each Ri 45 degrees within der, while being disposed in front of Panpa reinforcement of the vehicle body, the side flange after of said flange, is supported from the rear by the front side flange of Panpa reinforcement, Zhang of the rear side flange Interpersonal protection energy characterized in that it is used as a pedestrian protection member that absorbs collision energy applied to the bumper of an automobile due to a pedestrian collision by being joined to the front flange of the bumper reinforcement at the out flange portion Aluminum alloy extruded hollow shape for absorbent members.   The aluminum alloy extruded hollow member for personal protection energy absorbing member according to claim 1, wherein a difference between the tensile strength and 0.2% proof stress is 70 MPa or less.

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