JP4787728B2 - Body bumper beam and body shock absorber - Google Patents

Description

  The present invention is excellent in load energy absorption performance at the time of a vehicle body collision, particularly at the time of a collision with a pedestrian, alleviating the impact given to the human body, and having excellent characteristics for reducing damage to the pedestrian, and a vehicle body bumper beam This relates to the member.

  In order to ensure the safety of occupants and protect the impacted object, the body of an automobile or the like is equipped with a bumper system that reduces the impact load and absorbs the impact energy by itself deforming in the impact direction when the vehicle collides. .

  A typical bumper system is a steel or aluminum alloy bumper beam attached to the front surface of the bumper stay, a foamed resin cushioning material provided on the front surface, and further provided on the front surface, integrated with the vehicle outer surface. It is a bumper system composed of a bumper cover, which often becomes.

  In recent years, in order to reduce the weight of the vehicle body, an extruded hollow member made of aluminum alloy or the like has begun to be used for these bumper beams instead of steel. The bumper beam made of aluminum alloy is made of a hollow material having a mouth shape, a date shape, an eye shape or a substantially rectangular cross-sectional shape extending in the width direction and having an appropriate bend according to the outer shape of the vehicle body. The steel bumper beam is substantially the same except that the hollow material is often an open section member.

  These body bumper systems have a bumper beam supported by the body and a cushioning material made of foam material placed on the front surface. At the same time, the function of reducing impact load and absorbing impact energy is required.

  In addition to collisions with “high-rigidity objects” such as vehicles and other objects (guardrails, telephone poles, etc.) that have been demanded in the past as these impact energy absorption functions, At the same time, new characteristics for protecting pedestrians have been demanded.

  For example, damage to a pedestrian when a vehicle collides with a pedestrian is typical in the head, waist, and legs, and the European Vehicle Commission and others are implementing a new vehicle evaluation program (NCAP). . According to this, a pedestrian protection characteristic evaluation test method is proposed for each of the head, waist, and legs, which is becoming a standard evaluation method for vehicle pedestrian protection. Among these evaluation tests, the leg evaluation method, which is a part related to the bumper system, causes a leg impactor simulating a pedestrian's leg to collide with a bumper beam at a speed of 40 km / h. At the time of this collision, it is required that the outputs (acceleration, shear deformation amount, bending angle) of various sensors provided in the leg impactor become a certain value or less. In particular, the acceleration value is required to be 150 G or less.

  However, the bumper system disclosed so far was devised on the premise of collision with “high-rigidity objects” such as vehicles and other objects (guardrails, telephone poles, etc.). Most are designed on the premise of collision with a rigid and high-strength material. For this reason, in these bumper systems, at the time of a collision with the pedestrian's leg model, the acceleration in particular exceeds the regulation value among the evaluation values (acceleration, shear deformation amount, bending angle).

  In contrast, a bumper system designed with reduced strength and rigidity to support pedestrian protection, on the contrary, reduces impact load and absorbs impact energy when colliding with high-rigidity and high-strength objects. Function will be reduced. For this reason, the bumper system is required to have both contradictory functions.

  On the other hand, various ideas such as providing an impact absorbing device and an air bag on the front surface of the bumper beam (bumper reinforcing material) have been proposed, but have not yet been put to practical use. For this reason, it is usually (actually) supported by providing a relatively thick absorber (cushion material, energy absorbing member) such as urethane foam or polystyrene on the front side of the bumper beam and on the back side of the bumper cover. I have done it. However, there is a limit to the thickness of the absorber to be provided due to the vehicle body design, and there is a limit to the pedestrian protection performance (impact energy absorption function).

  On the other hand, conventionally, a bumper beam has been proposed in which, in addition to the absorber, an impact buffering member against a vehicle body collision is provided on the front surface. In such a bumper beam, the impact buffer member is deformed in the cross-sectional thickness direction (transverse cross-sectional direction) at the time of a vehicle body collision to buffer the impact of the vehicle body collision. According to this, the function of bumper beam (bumper reinforcement) can protect pedestrians without reducing the impact load reduction and impact energy absorption function when colliding with the original highly rigid and high strength impact object. Newly added bumper reinforcement can be provided.

  For example, in Patent Literature 1, the bumper beam is positioned away from the outer end surface of the bumper beam by a required amount, and extends from a contact wall portion that receives an impact from the object at the time of collision and a mounting wall portion that contacts the bumper beam. There has been proposed a shock absorbing member of a hollow structure having a support wall portion that supports a contact wall portion from the back side. The support wall has a curved support wall extending along the mounting wall in a region having a required width continuous to the mounting wall, and the object is placed on the contact wall. When an impact is applied through the bending support wall, the bending support wall is bent while being deformed in the bending direction.

  In Patent Document 2, at least two frame rails attached to the vehicle body, at least two brackets respectively connected to these frame rails, beam portions attached to these brackets, a plate member attached to the beam portions, A vehicle impact reduction bumper device having a frame rail extension connected to the bracket has been proposed.

  In Patent Document 3, the bellows shape is extended so that the bellows shape is parallel to the collision load from the front surface, and the bellows shape is deformed at the time of a pedestrian collision. An energy absorbing member for protecting people has been proposed that lowers the load and secures the amount of energy absorption necessary for protecting pedestrians.

Patent Document 4 includes a front flange and a rear flange provided substantially parallel to the longitudinal direction of the vehicle body, and left and right webs provided substantially parallel to connect the flanges. An energy-absorbing member for protecting people has been proposed, which is made of a hollow aluminum alloy that is curved toward the direction. According to this, each web is deformed at the time of a pedestrian collision, and the whole is deformed flatly just like the open / close state of a pantograph of a train, reducing the maximum load in load displacement and walking. Energy absorption necessary for the protection of the elderly.
JP 2004-114864 JP JP 2003-285704 A JP2003-312397 JP 2004-90910 A

  However, in Patent Document 1, since the buffer member is a resin hollow member, in order to obtain sufficient pedestrian leg protection performance, the thickness is made considerably thicker than that of a metal buffer material. There is a need to sacrifice weight. In addition, the material and thickness of the resin are also limited in the production, and there is a problem that the recyclability is inferior as compared with a metal cushioning material.

  On the other hand, in order to narrow the distance (gap) between the front side of the body of the bumper beam (bumper reinforcement) and the bumper cover, such as in car body design and small cars, an impact buffer member (for personal protection) The energy absorbing member is required to have a thinner width in the longitudinal direction of the vehicle body. In this regard, in the shock absorbing member as in Patent Document 2, the length of the plate member in the longitudinal direction of the vehicle body is relatively long in order to ensure the amount of energy absorption necessary for protecting the pedestrian (the plate member is the front surface of the bumper beam). It cannot be used depending on the design of the car body (model).

  Moreover, in an actual collision accident, the pedestrian's collision position is different. For this reason, the collision position of a pedestrian may largely shift with respect to the installation position of the energy absorbing member. That is, the collision position of the pedestrian leg is shifted in the vehicle width direction, the collision direction of the pedestrian leg is shifted from the horizontal direction, and the like. Corresponding to these cases, in order to cause the deformation expected of the buffer member (energy absorbing member), an energy absorbing member for protecting human beings having a relatively large area over the front surface of the bumper reinforcing material is necessary. It becomes.

  When the buffer member has a relatively large area as described above, the buffer member configured with a relatively thick wall as in Patent Documents 3 and 4 increases in weight and sacrifices weight reduction. Further, assuming that the collision direction of the pedestrian leg is deviated from the vertical direction of the vehicle body (vertical direction), in the buffer member using the crushing in the cross-sectional thickness direction of the profile as in Patent Documents 3 and 4, It means that the line of action of the compressive force is shifted. If the line of action of the compressive force is deviated, the energy absorption characteristics of the buffer member utilizing the crushing in the cross-sectional thickness direction are likely to deteriorate. Therefore, in this type of buffer member, the thickness of the cross-section must be increased in order to maintain this energy absorption characteristic even when the pedestrian collides with the collision position. Also from this point of view, it is difficult to secure the amount of energy absorption necessary for protection of pedestrians with the buffer members as in Patent Documents 3 and 4.

  Therefore, the object of the present invention is to reduce the generated load, acceleration, etc. at the time of collision even when the area is relatively large and the weight is light and the width is reduced (thinned) in the cross-sectional thickness direction. An object of the present invention is to provide a vehicle body bumper beam and a vehicle body shock-absorbing member having excellent protection characteristics for pedestrian legs.

In order to achieve the above object, the gist of the vehicle body bumper beam of the present invention is a vehicle body bumper beam having a hollow structure in which an impact buffering member is provided on the front surface side of the bumper beam body, and the bumper beam body is made of an aluminum alloy. It is made of a hollow extruded shape and has a flange extending from the rear surface wall in the vertical direction of the vehicle body. The shock absorbing member has a collision wall portion, a side wall portion, and a joining flange, and these have a thickness. are formed integrally by molding of the following metal plate 3.0 mm, the impact wall section, with projecting toward the front side of the bumper beam main body, the front surface of the bumper beam body extending in the vertical direction of the vehicle body over the entire region of the wall extending in the vertical direction of the vehicle body, said side wall portion, from each end of the vehicle body vertical direction of the impact wall section, the body before and after the bumper beam body And each extending toward the rear of the vehicle body along the outside of sidewall extending direction leads to a rear wall of the bumper beam main body, between the deflector portion and the side wall portion, to surround the bumper beam body vehicle body to form a shaped cross section of substantially C, while each overhang in the vertical direction of the vehicle body said joining flanges from each end of the vehicle body rear side of the side wall portions, a rear wall of the bumper beam main body It is joined to the flange extending in the vertical direction and supported from the rear wall side of the bumper beam main body .

  In order to reduce the maximum load in load displacement and ensure deformation in the cross-sectional thickness direction that secures the energy absorption necessary for protection of pedestrians, the impact wall of the impact cushioning member is the starting point of deformation at the time of vehicle collision. It is preferable to have a dent. Similarly, it is preferable that the impact buffer member is formed by integrally forming the collision wall portion, the side wall portion, and the joining flange by molding an aluminum alloy plate.

In order to achieve the above object, the gist of the shock absorbing member for a vehicle body of the present invention is a bumper beam that is formed of an aluminum alloy hollow extruded member and has a flange extending in the vertical direction of the vehicle body from the rear surface wall. 2. An impact buffering member against a vehicle body collision provided on the front surface side of the main body , comprising a collision wall portion, a side wall portion, and a joining flange, each having a thickness of 3. Are formed integrally by molding of 0mm following metal plate, the impact wall section with projecting toward the front side of the bumper beam body, the bumper beam body extending in the vertical direction of the vehicle body of the front wall extending in the vertical direction of the vehicle body over the entire region, the side wall portion, from each end of the vehicle body vertical direction of the impact wall section, along the outside of the side wall extending in the vehicle longitudinal direction of the bumper beam main body and each extending toward the rear of the vehicle body Te reaches up to the rear wall of the bumper beam main body, in a side wall portion and the collision wall portion, forming a shaped cross-sectional shape of a substantially U-shape surrounding the bumper beam body as well as, by each overhang in the vertical direction of the vehicle body said joining flanges from each end of the vehicle body rear side of the side wall portions, a flange extending in the vertical direction of the vehicle body from the rear wall of the bumper beam main body contact To, is to be supported from the wall side of the rear of the bumper beam main body.

  This impact buffer member reduces the maximum load in load displacement and ensures deformation in the cross-sectional thickness direction that secures energy absorption necessary for protection of pedestrians. It is preferable to have a dent serving as a starting point. Moreover, it is preferable that the said impact buffer member is what formed the said collision wall part, the side wall part, and the joining flange integrally by shaping | molding of an aluminum alloy plate.

  The vehicle body bumper beam of the present invention is characterized by the structure and shape of an impact buffering member against vehicle body collision provided on the front surface of the bumper beam. That is, in the vehicle body bumper beam according to the present invention, first, the collision wall portion of the shock absorbing member projects toward the front side of the bumper beam and extends over the entire region of the front wall of the bumper beam extending in the vertical direction of the vehicle body. Extends in the vertical direction.

  As described above, in the vehicle body bumper beam of the present invention, the area of the collision wall portion of the shock absorbing member is enlarged so as to extend over the front surface of the bumper beam (so that the entire surface of the bumper beam front wall can be covered). For this reason, an energy absorption function can be exhibited irrespective of a pedestrian's collision position. Further, the hollow structure itself formed by the bumper beam front wall and the collision wall portion can be enlarged, and the impact absorption and buffering function at the time of vehicle collision can be increased due to deformation of the hollow structure in the longitudinal direction of the vehicle body (cross-sectional thickness direction).

  Further, the side wall portion of the shock absorbing member extends from each end of the collision wall portion in the vehicle body vertical direction toward the rear of the vehicle body along the outside of the side wall extending in the vehicle body longitudinal direction of the bumper beam. The bumper beam reaches the rear wall, and the side wall portion and the collision wall portion form a substantially U-shaped cross-sectional shape surrounding the bumper beam. For this reason, in the present invention, the stroke (length) of the both side walls of the shock absorbing member becomes relatively long, and the deformation length in the vehicle longitudinal direction (cross-sectional thickness direction) of the both side walls due to the impact at the time of vehicle collision is reduced. become longer. As a result, the sudden rise of the load in the load-displacement relationship (curve) can be reduced, and the shock absorbing characteristic (pedestrian protection characteristic) at the time of collision can be improved. In addition, it does not adversely affect the characteristics such as strength on the bumper beam 10 side. Furthermore, it is possible to change the energy absorption characteristics and increase the degree of freedom of design.

  Further, the joining flange of the shock absorbing member is joined to a flange projecting in the vertical direction of the vehicle body from each end on the vehicle body rear side of the both side walls and extending in the vertical direction of the vehicle body from the rear wall of the bumper beam. Thus, the shock absorbing member is supported from the rear wall side of the bumper beam. Such support and joining are continuously performed over the longitudinal direction (vehicle body width direction) of the bumper beam and the shock absorbing member.

  For this reason, the joint between the shock-absorbing member and the bumper beam becomes a joint between the flanges, and a general-purpose mechanical joining means such as a bolt or a rivet or a general-purpose welding joining means such as spot welding can be employed. As a result, the number of options for joining increases and the joining itself becomes simple. Thereby, it is possible to control the support and bonding force of the shock absorbing member to the bumper beam over the longitudinal direction of the shock absorbing member. In other words, the amount of energy absorption necessary to protect pedestrians is secured, and the shock absorbing member is controlled to ensure deformation in the longitudinal direction of the vehicle body (cross-sectional thickness direction), and the reaction force and acceleration generated in the event of a collision are controlled. It can also be controlled.

  Each member of the impact wall portion, the side wall portion, and the joining flange of the impact buffer member, such as the impact buffer member formed of a single aluminum alloy plate, It is integrally formed of a metal material of 0 mm or less. This makes it easier to manufacture the shock absorbing member as compared to a case where the members divided into the collision wall portion, the side wall portion, and the joining flange are joined and integrated. In addition, each joint portion is not broken by an impact at the time of a vehicle body collision, and the energy absorption function at the time of the collision can be improved.

  Therefore, the vehicle body bumper beam of the present invention can reduce the generated load, acceleration, etc. at the time of collision even when the shock absorbing member is relatively narrow (thinned), and can secure the characteristics necessary for protecting pedestrians. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of the vehicle body bumper beam of the present invention provided on the front side or rear side of the vehicle body, and an embodiment in which the metal shock absorbing member of the present invention is attached to the front surface side of the vehicle body bumper beam. . FIG. 2 is a perspective view showing another aspect of only the shock absorbing member to be attached.

  1 and 2, the metal shock-absorbing member 1 of the present invention has, as a basic structure, a collision wall portion 2 on the front side of the vehicle body, side walls 3 on the upper and lower sides (upper side in the figure), 4 (lower side in the figure). ) And upper and lower joining flanges 5 (upper side in the figure) and 6 (lower side in the figure).

The bumper beam 10 in FIGS. 1 and 2 is a hollow formed of a front wall 11 on the front side of the vehicle body, side walls 13 (upper side in the figure) and 14 (lower side in the figure), and a rear wall 12. (Cross section) structure. The rear wall 12 has two flanges 15 (upper side in the figure) and 16 (lower side in the figure) that extend in the vertical direction of the vehicle body. The flanges 5 and 6 of the shock-absorbing member 1 are joined on the surface side of the flanges 15 and 16 (front side: right side in the drawing). Here, the bumper beam 10 in FIGS. 1 and 2 means a bumper beam body.

  This is one mode in which the flanges 5 and 6 of the shock absorbing member 1 are supported from the rear wall side of the bumper beam. In the bumper beam 10 shown in FIGS. 1 and 2, flanges 15 and 16 for supporting the flanges 5 and 6 (of the shock absorbing member 1) are projected from the extension line (on the same surface) of the rear wall 12. . However, although these flanges 15 and 16 are on the rear wall 12 side of the bumper beam, the upper side wall (web) 13 and the lower side wall (web) 14 on the front side of the rear wall 12 are arranged in the vertical direction of the vehicle body. You may overhang each. However, in this case, the length of the side walls 3 and 4 is shorter than the support on the extension line of the rear wall 12 of FIGS. The front side of the rear wall 12 is such that the member performance is not deteriorated.

  In FIGS. 1 and 2, the arrow F indicates the load direction at the time of vehicle collision. In FIGS. 1 and 2, the load direction at the time of vehicle collision is from right to left in the drawing, and the right side of the drawing is the bumper beam or the vehicle body. Indicates the front or rear side. Also, a vehicle body panel (bumper cover, hood, trunk, etc.) is shown on the right side of the shock absorbing member 1 by a one-dot chain line 22.

  Although not shown in FIGS. 1 and 2, an absorber made of PP foam or the like may be disposed as usual between the shock absorbing member 1 and the vehicle body indicated by a one-dot chain line. Further, a steel or aluminum alloy stay, a steel vehicle body side member, and the like that support the bumper beam 10 are sequentially arranged on the rear side of the vehicle body of the bumper beam 10 (left side in the drawing). In the present invention, the thickness of the absorber can be made thinner or smaller than in the prior art, and it is possible to use no absorber.

(Collision wall)
1 and 2, the collision wall portion 2 of the metal shock absorbing member 1 projects toward the front side of the bumper beam 10 and extends in the vehicle body vertical direction (vertical direction in the figure). It extends in the vertical direction of the vehicle body over the entire area of the front wall 11 of the bumper beam (all areas in the vertical direction of the vehicle body). The shape of the collision wall portion 2 in the vertical direction of the vehicle body has a dome shape that protrudes toward the front of the bumper beam 10 and curves. When the vehicle collides with a pedestrian, the entire collision wall portion 2 is deformed in the longitudinal direction of the vehicle body (cross-sectional thickness direction) and becomes a main portion that absorbs and cushions the impact of the collision.

  Thus, the collision wall portion 2 extends over the entire area of the front wall 11 of the front wall 11 of the bumper beam 10 in the vertical direction of the vehicle body (the entire surface of the bumper beam front wall 11 in the vertical direction of the vehicle body). Enlarge to be able to cover. For this reason, the energy absorption function can be exhibited regardless of the shift in the vehicle body vertical direction (vertical direction) of the collision position of the pedestrian with respect to the bumper beam 10. Moreover, the hollow structure itself comprised by the bumper beam front wall 11 and the collision wall part 2 can be enlarged. For this reason, it is possible to increase the shock absorption and shock absorbing function at the time of the vehicle body collision due to the deformation of the collision wall portion 2 in the longitudinal direction of the vehicle body.

  The shape of the collision wall 2 can be freely selected as long as the collision wall 2 protrudes toward the front side of the bumper beam 10. That is, as shown in FIG. 1, it may be formed as an arc shape without side walls 3 and 4 with no corners (no corners or squares). Alternatively, the corner portions of the large shoulder R may be provided in the vertical direction of the vehicle body, which may be the opposite ends of the collision wall portion 2 in the vertical direction of the vehicle body and the intersections with the side walls 3 and 4. However, when a corner (corner) is provided, this is likely to be a starting point of destruction. Therefore, it is preferable to eliminate the corner by using a large shoulder R or an arc as shown in FIG. When there is the corner portion, the corner portion becomes each end portion of the collision wall portion 2 in the vertical direction of the vehicle body in the present invention. However, when the corners are eliminated, the end portions in the vehicle body vertical direction of the collision wall 2 referred to in the present invention are the substantially horizontal side walls 3 and 4 and the substantially vertical collision wall 2. A suitable intersection.

  In the present invention, the collision wall portion 2 extends over the entire region of the front wall 11 of the front wall 11 of the bumper beam 10 in the vertical direction, but the longitudinal direction (vehicle width direction) is the longitudinal direction of the front wall 11 ( It is not necessary to extend over the entire region (entire region) in the vehicle body width direction). 1 and 2, the metal shock absorbing member 1 of the present invention has a typical structure in which the single shock absorbing member 1 is disposed in the entire longitudinal direction (vehicle width direction) of the bumper beam 10. The case where it extends in a row is illustrated.

  On the other hand, the shock absorbing member 1 and the collision wall portion 2 are partially or divided only in a necessary portion in the longitudinal direction (vehicle body width direction) of the front wall 11 of the bumper beam 10 or only in a necessary length. A plurality of them may be provided. Further, the collision wall portion 2 may be partially cut out only in an unnecessary portion (unnecessary portion) on the front surface in the longitudinal direction (vehicle body width direction) of the front wall 11 of the bumper beam 10.

  When the impact buffer member 1 and the collision wall portion 2 are provided in a partially or divided manner, the bumper beam 10 is supported from the rear surface by a stay or the like. It is necessary to protect the pedestrian legs at both ends of the bumper beam 10 that is provided, and the shock absorbing members 1 are provided indispensably.

  On the other hand, the central portion of the bumper beam 10 in the longitudinal direction (vehicle body width direction) may be provided with only the absorber without providing the shock absorbing member 1 partially. As described above, when the shock absorbing member 1 and the collision wall portion 2 are provided partially or divided, only the necessary portion on the front surface in the longitudinal direction of the front wall 11 of the bumper beam 10 or only the necessary length is provided. The impact buffer member can be reduced in weight.

(Sidewall)
The upper and lower side wall portions 3 (upper side in the drawing) and 4 (lower side in the drawing) of the shock absorbing member 1 extend from the end portions of the collision wall portion 2 in the vertical direction of the vehicle body in the vehicle longitudinal direction of the bumper beam 10. Each extends toward the rear of the vehicle body along the outside of the existing side walls 13 and 14 and extends to the rear wall 12 of the bumper beam. As a result, the side wall parts 3 and 4 and the collision wall part 2 form a substantially U-shaped cross-sectional shape surrounding the bumper beam 10.

  Thus, in the present invention, the stroke (length) of the side walls 3 and 4 of the shock absorbing member 1 is the amount of protrusion of the collision wall 2 toward the front of the vehicle body (the collision wall from the bumper beam front wall 11). And the lengths of the side walls 13 and 14 of the bumper beam 10 extending in the longitudinal direction of the vehicle body. For this reason, the side wall parts 3 and 4 of the shock absorbing member 1 have a relatively large stroke (length). On the other hand, when the flanges 5 and 6 of the shock absorbing member 1 are supported by the front wall 11 or the side walls 13 and 14 of the bumper beam 10 (extend from the front wall or side wall portion of the bumper beam). The stroke of the both side walls of the shock absorbing member must be considerably smaller than the both side walls 3, 4 of the shock absorbing member 1 of the present invention.

  That is, even if the collision wall portion 2 does not protrude so much from the front surface of the vehicle body from the bumper beam front wall 11 and extends along the bumper beam front wall 11, at least the length of the bumper beam side walls 13 and 14 is sufficient. The stroke of the side walls 3 and 4 is always ensured. For this reason, in the present invention, the deformation length in the longitudinal direction of the vehicle body (cross-sectional thickness direction) of the side wall portions 3 and 4 due to the impact at the time of the vehicle body collision is increased, and the load suddenly rises in the load-displacement relationship (curve). It can reduce and can improve the buffer characteristic (pedestrian protection characteristic) at the time of a collision. In addition, it does not adversely affect the characteristics such as strength on the bumper beam 10 side.

(Flange)
1 and 2, flanges 5 and 6 that are mounting walls of the shock absorbing member 1 are flanges 15 that are part of the rear wall 12 of the bumper beam from the end portions of the side walls 3 and 4 on the rear side of the vehicle body. It has a shape that extends in the vertical direction of the vehicle body along the upper side) and 16 (lower side in the figure) and abuts on the front side (the right side in the figure) of each flange 15 and 16. In the flanges 15 and 16, the flanges 5 and 6 of the shock absorbing member 1 are joined by a mechanical joining means 21 or the like. 1 and 2, as shown in FIGS. 1 and 2, the flanges 15 and 16 of the bumper beam 10 and the flanges 5 and 6 of the shock absorbing member 1 are appropriately arranged in the longitudinal direction (vehicle body width direction). It is performed at intervals as required.

  As described above, for this reason, if the shock-absorbing member 1 and the bumper beam 10 are joined to each other by flanges, general-purpose mechanical joining means 21 such as bolts and rivets, and general-purpose such as spot welding are used. The welded joining means that can be used can be employed, the choice of joining increases, and the joining itself is simplified.

  Further, as described above, the shock absorbing member 1 is supported on the rear wall 12 side of the bumper beam 10. As a result, due to the synergistic effect of joining the flanges described above, the support and joining force of the shock absorbing member 1 to the bumper beam 10 can be freely partially or entirely over the longitudinal direction of the shock absorbing member 1. It is possible to control. For example, when the support and joining force of the shock absorbing member 1 is a relatively strong joining strength (supporting strength), the support surface of the shock absorbing member becomes a wide area of the front wall of the bumper beam, and the collision load is Even when the joint is localized when loaded, the joint is less likely to break. For this reason, the deformation | transformation of the cross-sectional thickness direction of a hollow structure only to ensure the amount of energy absorption required for protection of a pedestrian is securable. On the other hand, when making this a relatively weak joint strength, it is possible to increase the interval of bolts, spot welding, etc., thereby reducing the reaction force and acceleration generated at the time of collision of welding joint means commonly used. Can be suppressed.

  In Patent Document 2, the mounting wall portion of the shock absorbing member is joined to the upper and lower wall surfaces of the bumper beam. However, when the mounting wall of the shock absorbing member is joined to the upper and lower wall surfaces of the bumper beam in this way, when the bumper beam has a closed cross section, it is joined only from one side from the mounting wall of the shock absorbing member ( Cannot be combined) In this one-side joining method, there is no choice but to weld or make a pilot hole and join with a blind rivet or the like. At this time, if welding is used, if the bumper beam is made of an aluminum alloy, the strength is partially reduced due to the thermal effect during welding. Further, in the blind rivet, an extra work for making a pilot hole is required, and the bonding strength is weakened. For this reason, the force which supports the attachment wall part of an impact buffer member becomes weak, and when a collision load is applied, the local joint part of both tends to break. Therefore, it is difficult to ensure the deformation in the cross-sectional thickness direction that secures the energy absorption necessary for protecting the pedestrian. In Patent Document 2, a hollow structure is formed by the point that the collision wall portion and the mounting wall portion are integrally formed of a thin metal plate, or the bumper beam front surface and the collision wall portion. It is the same as the present invention in that the impact of the vehicle body collision is buffered by being deformed in the direction. However, since it is attached to the upper and lower wall surfaces of the bumper beam, the problem of the one-sided joint described above and, as described above, the stroke of the side wall portion of the shock absorbing member is relatively short, and the compression deformation length of the shock absorbing member is shortened. There's a problem. As a result, the initial load in the load displacement becomes high, and there are disadvantages such as a decrease in buffer characteristics (pedestrian protection characteristics).

(Flange joining method)
The flanges 5 and 6 of the shock absorbing member 1 may be joined to the bumper beam flanges 15 and 16 by mechanical joining 21 such as rivets and bolts. Instead of this, it may be welded in combination with this. This joining position is arbitrary as long as the joining strength can be ensured, and it extends over the longitudinal direction (vehicle body width direction) of the bumper beam 10 (flanges 15 and 16) and the shock absorbing member 1 (flanges 5 and 6). , Provided at appropriate intervals. Note that the bonding strength (support strength) of the shock absorbing member 1 can be changed by changing the bonding position or the bonding interval. For example, at a site where a strong bonding strength is required, the bonding strength (bonding force) can be increased by selecting a bonding method having a high bonding force or by reducing the bonding pitch. Further, when it is desired to suppress the reaction force and acceleration generated at the time of collision low, the bonding strength (bonding force) can be reduced by selecting a bonding method with a low bonding force or increasing the bonding pitch.

(Thin plate integrated)
The impact wall portion 2, the side wall portions 3 and 4, and the joining flanges 5 and 6 of the shock absorbing member 1 are integrally formed from a metal material having a thickness of 3.0 mm or less. That is, each member of the collision wall portion 2, the side wall portions 3 and 4, and the joining flanges 5 and 6, such as a single aluminum alloy plate, is formed by 3. It is integrally formed of a metal material of 0 mm or less. As a result, the shock absorbing member can be easily manufactured as compared with the case where the members divided into the collision wall portion, the side wall portion, and the joining flange are joined and integrated. In addition, each joint portion is not broken by an impact at the time of a vehicle body collision, and the energy absorption function at the time of the collision can be improved. Of course, the thicknesses of the collision wall portion 2, the side wall portions 3, 4 and the joining flanges 5, 6 may be uniform (same) or may not be uniform (different) depending on the required characteristics. . At this time, at least the thickness of the collision wall portion 2 is set to 3.0 mm or less, more preferably 2.0 mm or less.

  As the metal material, a metal thin plate having a thickness (thickness) of 3.0 mm or less is preferable. Examples of the aluminum alloy material include an aluminum alloy thin plate having a plate thickness of 3.0 mm or less. Moreover, as a steel material with high strength, a thin steel plate having a plate thickness of 1.5 mm or less is preferable. It is preferable that the impact buffer member 1 is integrally formed with the impact wall portion 2, the side wall portions 3, 4, and the joining flanges 5, 6 by press forming these thin plates.

If the thickness or plate thickness is not small (thickness is not thin), the deformation in the cross-sectional thickness direction that secures the amount of energy absorption necessary for protecting the pedestrian, starting from the collision load load at the time of the pedestrian collision begins to occur. The load becomes high and the function as an impact buffering member cannot be exhibited. In addition, when the thickness exceeds 3.0 mm, the weight increases and the weight can be reduced even if an aluminum alloy thin plate is used when used for a large (wide) area over the entire front surface of the bumper beam. difficulties and that Do not.

  Moreover, when these divided | segmented members are joined and integrated without integrating the collision wall part 2, the side wall parts 3 and 4, and the joining flanges 5 and 6, the divided part thru | or joined part are Inevitably exists. For this reason, it becomes easy to fracture | rupture from these division | segmentation parts thru | or a junction part, and also the deformation | transformation of the cross-sectional thickness direction which ensures the energy absorption amount required for a pedestrian's protection becomes difficult to occur, and the function as an impact buffer member cannot be exhibited. Moreover, the process and cost of manufacturing the shock absorbing member will increase.

(Deformation part)
Here, as shown in FIG. 2, in order to facilitate the deformation in the cross-sectional thickness direction triggered by the collision load load at the time of the pedestrian collision, the collision wall 2 is formed at the center in the vertical direction. It is preferable to have the deformed portion 7 which is a dent (concave portion) serving as a starting point of deformation. The dent deforming portion 7 extends over the vehicle body width direction (longitudinal direction) of the collision wall portion 2 in order to exert an effect of facilitating deformation in the cross-sectional thickness direction regardless of the pedestrian collision position. To be provided. Therefore, the shock-absorbing member 1 provided with the deformed portion 7 of FIG. 2 is a so-called double mountain-shaped cross section formed by the recess 7 as compared with the dome-type shock-absorbing member of FIG. It has a hollow shape. In addition, the meaning of the dent means that it is retracted or recessed with respect to the load direction F.

  As will be explained in the examples described later, the double mountain type shock-absorbing member of FIG. 2 provided with the deformable portion 7 that easily causes the deformation in the thickness direction of the cross section (transverse cross-sectional deformation) does not include the deformable portion 7. If the other conditions are the same as those of the dome-type impact buffer member, the maximum acceleration (maximum load) is small and the energy absorption amount is relatively large. In order to exhibit the effect of facilitating deformation in the cross-sectional thickness direction, the deformed portion 5 does not necessarily have to be the dent, and can be a notched portion or a thinner portion than other portions. . However, a dent is preferable because it is easy to integrally form the shock-absorbing member when it is press-molded from the base plate and the effect of promoting deformation is easily exhibited.

(Shape in the longitudinal direction of the entire shock absorbing member)
In FIGS. 1 and 2, the bumper beam 10 is not linear due to the design of the vehicle body, but has both ends retreated and curved in the longitudinal direction of the vehicle body, and the entire shape is curved in the vehicle body width direction over the longitudinal direction. is doing. For this reason, the shock absorbing member 1 also has a shape in which both end portions are retracted and curved in the longitudinal direction of the vehicle body in accordance with the curved shape of the bumper beam 10 and the entire body is curved in the vehicle body width direction over the longitudinal direction. is doing. As described above, the shape of the entire shock absorbing member 1 in the longitudinal direction is adapted to the shape of the entire bumper beam 10 in the longitudinal direction, such as linear if the shape of the bumper beam 10 in the vehicle body width direction is linear. Shall be.

(Other aspects of shock absorbing member)
As another aspect of the shock absorbing member, either one or both of the joining flanges 5 and 6 of the shock absorbing member 1 are arranged along the back side (the left side surface in the drawing) of the flanges 15 and 16 of the bumper beam 10. , You may join. In such a case, the length of the collision wall portion 2 of the shock absorbing member 1 in the vertical direction of the vehicle body or the interval between the side wall portions 3 and 4 in the vertical direction of the vehicle body is determined by the bumper including the flanges 15 and 16 of the bumper beam 10. As long as the length (height) of the beam 10 in the vertical direction of the vehicle body is ensured, the linearity of the side walls 3 and 4 extending to the rear of the vehicle body is ensured. However, the supporting force of the shock absorbing member 1 is reduced as compared with the case of FIGS.

(Material of shock absorbing member)
The material of the shock absorbing member having a plate thickness of 3.0 mm or less may be a normal steel plate or a high-tensile steel plate, but it is lightweight and has a large energy absorption effect even when used over a large area over the entire front surface of the bumper beam. Aluminum alloys are preferred. This type of aluminum alloy, typically as a thin plate, are generally used in this type structural member application, referred to in AA to JIS specification, 3000 series, well relatively high yield strength formability, 5000, 6000 A general-purpose (standard) aluminum alloy such as O, T4, T5, T6, T7, etc. that has been tempered or heat-treated in accordance with required performance such as O, T4, T6, and T7 is suitably and selectively used.

(Bumper beam)
The bumper beam 10 shown in FIGS. 1 and 2 connects the front wall 11 and the rear wall 12, and has a mouth-shaped cross-section hollow portion composed of an upper side wall 13 and a lower side wall 14 that are arranged substantially in parallel with each other. Have Moreover, it has two flanges 15 (upper side) and 16 (lower side) respectively extending from the rear wall 12 of the bumper beam in the vertical direction of the vehicle body. The flanges 15 and 16 are not provided in that the attachment wall portions 3 (upper side) and 4 (lower side) of the shock absorbing member 1 are joined, and the front wall 11 is joined to the attachment wall portions 3 and 4 directly. Easy to do and efficient. However, as a mode of supporting the flanges 5 and 6 of the shock absorbing member 1 from the rear wall side of the bumper beam, the flanges 15 and 16 are not necessarily on the extension line of the rear wall 12 (same as in FIGS. It is not necessary to overhang from the surface. For example, although these flanges 15 and 16 are on the rear wall 12 side of the bumper beam, the upper side wall 13 and the lower side wall 14 on the front side in the front-rear direction of the vehicle body from the rear wall 12 respectively in the vertical direction of the vehicle body. It is good also as an aspect which is made to project and this supports the flanges 5 and 6 of the impact buffering member 1 from the rear wall side of the bumper beam.

(Other aspects of bumper beam)
An intermediate rib may be provided as an aspect in which the deformation strength in the cross-sectional thickness direction (vehicle body longitudinal direction: lateral direction) of the hollow portion of the bumper beam 10 shown in FIGS. In the hollow portion of the mouth-shaped cross section of the beam 10, one inner rib may be inserted in the lateral direction to form a daily section, or two inner ribs may be inserted in parallel in the lateral direction to form an eye-shaped section. Also, a cross-shaped or X-shaped middle rib may be inserted into the mouth-shaped cross-section hollow portion of the bumper beam 10 of FIGS. Furthermore, the corner R of the connecting portion (corner portion) between the upper and lower side walls 13 and 14 and the rear wall 12 of the bumper beam 10 is increased in combination with or without these intermediate ribs, and the cross-sectional thickness direction of the hollow portion is increased. The deformation strength may be improved.

In these examples, including the bumper beam 10 shown in FIGS. 1 and 2, the material of the bumper beam is an aluminum alloy, and an aluminum alloy hollow extruded shape is used because of the ease of forming a hollow cross-sectional shape extending in the longitudinal direction. The embodiment is intended. Bumper beam 10 is a good Ri lightweight, energy absorbing effect is large due to plate thickness effect of a metal sheet, an aluminum alloy is preferred. Generally used for this kind of structural member, 3000 series, which is generally used for AA or JIS standards, and 5000 series, 6000 series, 7000 series etc. Extruded shapes (those that have been tempered or heat-treated to meet the required performance of O, T4, T5, T6, T7, etc.) are preferably and selectively used.

  In addition, although the suitable example was shown as mentioned above, the material of the cross section thickness direction (transverse section) on the bumper beam side and the material made of steel, aluminum alloy, etc. are mainly determined from the convenience of the automobile design side. For this reason, the present invention can be applied to various bumper beams such as various cross-sectional thickness direction (transverse cross-sectional) shapes, longitudinal direction shapes, and materials, which are determined on the vehicle design side, regardless of the above preferred examples.

  The bumper beam of the present invention shown in FIG. 1 and FIG. 2 is modeled as an analysis, and the acceleration-displacement relationship is analyzed by static crush analysis under load assuming a pedestrian collision using general-purpose finite element analysis software ABAQUS. I asked for. In this analysis model of the invention example, no absorber is provided. However, as an aspect of use of the present invention, an absorber made of PP foam or the like may be disposed (combined with the absorber) on the front side of the shock absorbing member 1. Also, as shown in FIG. 3, in the lower part of the bumper beam, at the time of collision, the lower part of the leg is kicked up by the force of F1 indicated by the arrow in the direction opposite to the collision direction, and the leg is bent excessively ( It may be combined with another means 20 for preventing a large bending angle.

  FIG. 3 shows the analysis model. In FIG. 3, 10 is the bumper beam of the present invention shown in FIG. 1, 11 and 12 are the front wall and rear wall of the bumper beam, 1 is the shock absorbing member, 2, 3, and 4 are the collision wall portion and the side wall portion of the shock absorbing member. is there. Reference numeral 22 denotes a vehicle body panel, 30 denotes a leg impactor model simulating a pedestrian leg according to the new vehicle evaluation program of the European Vehicle Commission, and 31 denotes a knee (joint) portion.

  In FIG. 3, the impact position (height) h of the bumper beam 10 indicates the height (mm) from the ground, and is made constant at 340.0 mm according to the new vehicle evaluation program of the European Vehicle Commission. In addition, it was assumed that the legs of the pedestrian collide at a position shifted by 100 mm or 300 mm in the longitudinal direction (vehicle body width direction) from the longitudinal center of the bumper beam 10. This is shown in Table 1 as the striking position.

  In this analysis, the load (acceleration) received by a leg impactor when a leg impactor simulating a pedestrian's leg collided at a speed of 40 km / h (initial speed) according to the evaluation test of the European Vehicle Commission. ), Knee bending angle (collision direction), and knee shear displacement (collision direction). The evaluation is performed according to the standards of the European Vehicle Commission, and the load (acceleration) received by the leg impactor 30 is 150 G or less, the knee bending angle is 15.0 ° or less, and the knee shear displacement is 5.0 or less. It became the standard of acceptance. These results are shown in Table 1.

  For comparison, the shock-absorbing member of the present invention is not provided, and the bumper beam 10 shown in FIG. 1 has a foaming ratio of 11 times on the front side of the bumper beam 10. The bumper beams of comparative examples (conventional examples) 7 and 8 in which only a 40 mm-thick absorber is arranged were analyzed in the same manner.

  The analysis conditions were the following common conditions for both the above invention examples and comparative examples. That is, as shown in FIG. 1, the load is applied as indicated by an arrow F to the front and center of each bumper beam 10 (of the shock absorbing member 1). The shock absorbing member 1 was a JIS 6022 aluminum alloy plate H tempered material, a press-formed product of two types of plates having a plate thickness of 0.8 mm and a thickness of 1.2 mm.

  The external dimensions of the shock-absorbing member 1 that is a press-molded product are commonly 1400 mm in length (vehicle width direction), the same as that of the bumper beam 10, 90 mm in the maximum height of the collision wall 2 (vehicle body vertical direction), The maximum overhang length of the wall portion 2 (the overhang length in the longitudinal direction of the vehicle body from the front wall 11 of the bumper beam) is 50 mm, and the lengths of the side wall portions 3 and 4 (the vehicle body from the flanges 5 and 6 to the collision wall portion 2) The length in the front-rear direction was 95 mm. The length of the flanges 5 and 6 in the vertical direction of the vehicle body was 15 mm. Further, in the case where there is a dent 7 over the entire length of the shock absorbing member 1, the width (the vehicle body vertical direction) of the dent 7 is 70 mm and the depth (vehicle body longitudinal direction) is 10 mm.

  The bumper beam 10 was a 7000 series aluminum alloy extruded shape T5 tempered material and had a thickness of 3.0 mm. The external dimensions are commonly length (vehicle width direction) 1300 mm, front wall 11 and rear wall 12 height (car body vertical direction) 87 mm, front wall 11 thickness 2.3 mm, rear wall 12 thickness. The length was 2.0 mm, the length of each of the flanges 15 and 16 (vehicle body vertical direction) was 15 mm, the length of each of the side walls 13 and 14 (vehicle body longitudinal direction) was 38 mm, and each thickness was 2.2 mm.

  From the results of Table 1, Invention Examples 1 to 6 of the type of FIGS. 1 and 2 have a small maximum load and a large amount of energy absorption (EA) even when the leg hitting position of the pedestrian is shifted. As a result, the load (acceleration) received by the leg impactor, the knee bending angle (collision direction), and the knee shear displacement (collision direction) are small and satisfy the acceptance criteria of the European Vehicle Commission. Therefore, it turns out that the example of an invention has little damage with respect to the leg part of the pedestrian at the time of a collision.

  On the other hand, comparative examples (conventional examples) 7 and 8 in which only the absorber made of PP foam is disposed on the front side of the bumper beam 10 shown in FIG. The load (acceleration) received by the club impactor 30, the knee bending angle, the knee shear displacement, and the like exceed the standards for passing the European Vehicle Commission. This means that, despite the presence of the absorber, the leg portion collides with the front side of the bumper beam 10 at an early stage, and a sudden load rise occurs early. Therefore, it is confirmed that the conventional absorber alone causes a large damage to the pedestrian's leg at the time of collision.

  According to the present invention, even in a relatively thin outer dimension, the maximum load in load displacement can be reduced, and the deformation in the cross-sectional direction necessary for energy absorption with an appropriate collision load commensurate with a pedestrian collision is achieved. Can result. As a result, it is possible to provide a bumper beam and an impact buffering member having a function of reliably protecting a human such as a pedestrian. In addition, it is possible to provide a bumper beam to which a pedestrian protection function is newly added without deteriorating the original function of the bumper beam. For this reason, an effective pedestrian protection effect can be given to a bumper beam.

It is a perspective view which shows the one aspect | mode of this invention vehicle body bumper beam. It is a perspective view which shows the other aspect of this invention vehicle body bumper beam. It is explanatory drawing which shows the aspect of an analysis of this invention vehicle body bumper beam characteristic.

Explanation of symbols

1: shock absorbing member, 2: collision wall portion, 3, 4: side wall portion, 5, 6: flange,
7: dent, 10: bumper beam, 11: bumper beam front wall,
12: Bumper beam rear wall, 13, 14: Bumper beam side wall,
15, 16: Bumper beam flange, 21: Joining means, 22: Body panel,
30: Pedestrian leg model, 31: Knee

Claims (5)

A vehicle body bumper beam having a hollow structure in which an impact buffering member is provided on the front surface side of the bumper beam main body , the bumper beam main body being formed of an aluminum alloy hollow extruded shape and extending from the rear wall to the vehicle body vertical direction. The impact buffering member has a collision wall portion, a side wall portion, and a joining flange, and these are integrally formed by molding a metal plate having a thickness of 3.0 mm or less, the collision wall, together with the protruding toward the front side of the bumper beam main body, extending in the vertical direction of the vehicle body over the entire region of the front wall of the bumper beam body extending in the vertical direction of the vehicle body, the sidewall portions from each end of the vehicle body vertical direction of the impact wall section, each extended toward the rear of the vehicle body along the outer side wall extending in the vehicle longitudinal direction of the bumper beam main body Leads to the rear wall of the bumper beam main body, in a side wall portion and the collision wall portion, to form a shaped cross-sectional shape of a substantially U-shape surrounding the bumper beam body, the both sides the joining flange from each end of the vehicle body rear side of the wall portion by each overhang in the vertical direction of the vehicle body, by joining the flanges extending in the vertical direction of the vehicle body from the rear wall of the bumper beam main body, from the wall side of the rear of the bumper beam main body Body bumper beam characterized by being supported.   The vehicle body bumper beam according to claim 1, wherein the collision wall portion of the impact buffering member has a recess serving as a starting point of deformation at the time of vehicle body collision. 3. The vehicle body bumper beam according to claim 1 , wherein the impact buffer member is formed by integrally forming the collision wall portion, the side wall portion, and the joining flange by molding an aluminum alloy plate. A shock-absorbing member for a vehicle body collision, which is provided on the front side of a bumper beam body, which is formed of an aluminum alloy hollow extruded shape and has a flange extending from the rear surface wall in the vertical direction of the vehicle body. and a joining flange and the wall and the side wall portion, which is integrally formed by molding of the following metal plate thickness 3.0 mm, the collision wall, toward the front side of the bumper beam main body with projecting Te, extends over the entire area of the front wall of the bumper beam body extending in the vertical direction of the vehicle body in the vertical direction of the vehicle body, said side wall portion, the vehicle body vertical direction at each end of the impact wall section from parts, said respectively extend toward the rear of the vehicle body along the outer side wall extending in the vehicle longitudinal direction of the bumper beam main body, reaches up to the rear wall of the bumper beam body, the side In parts and the collision wall portion, to form a shaped cross-sectional shape of a substantially U-shape surrounding the bumper beam body, the vehicle body vertical direction the joining flange from each end of the vehicle body rear side of the side wall portions by each overhang on the bumper beam from rear wall of the body and joined with a flange extending in the vertical direction of the vehicle body, the vehicle body shock absorbing member characterized by being supported from the wall side of the rear of the bumper beam main body. The impact buffering member for a vehicle body according to claim 4 , wherein the impact buffering member is formed by integrally forming the collision wall portion, the side wall portion, and the joining flange by molding an aluminum alloy plate.

Images