JP2012020684A - Vehicular shock absorbing body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that can secure necessary load bearing capacity, even if weight reduction is carried out in a vehicular shock absorbing body, such as a lower absorber.SOLUTION: The tabular vehicular shock absorbing body 1 which is substantially arranged in parallel with a plane containing a vehicle front-back direction and a vehicle width direction, while being installed in a lower area of the vehicle front, so that a first direction W which is the front-back direction may become parallel to the vehicle width direction, has a plurality of reinforcement ribs 6 which project from a plate surface of the vehicular shock absorbing body 1, and extends in a second direction L which is orthogonal to the first direction W within the plate surface, and at least either of reinforcement ribs 6 which adjoin mutually has a branch rib 7 which is formed at the end of the reinforcement rib 6 and branches and extends from the end. The reinforcement ribs 6 which adjoin mutually are connected mutually in an integrated fashion through the branch rib 7.

Description

  The present invention relates to a vehicle impact absorber that is installed in a lower region in front of a vehicle.

  Conventionally, a protective device for reducing injury to a pedestrian when the vehicle collides with a pedestrian and ensuring the safety of the pedestrian is installed in front of the vehicle.

  In the front bumper, a bumper absorber made of a resin foam or the like disposed between the bumper reinforcement and the bumper fascia and having a shock absorbing performance, and a flat lower absorber arranged in the lower part of the bumper are known. . Among these, the flat lower absorber is provided with required rigidity, and when the vehicle collides with a pedestrian, it contacts the pedestrian's leg and acts as a so-called leg-pasting material. That is, the lower absorber has a function of preventing the pedestrian from being caught in the lower part of the vehicle by paying the pedestrian's legs and jumping up the pedestrian onto the hood of the vehicle (automobile). At the same time, it is preferable that the lower absorber is also provided with a function of absorbing an impact on a pedestrian.

  In order to ensure such a function, the lower absorber must surely jump up the leg of the pedestrian while suppressing injury to the leg (mainly the knee) when colliding with the pedestrian, For this purpose, it is necessary to apply a high load only to the lower side of the leg part of the pedestrian. Therefore, the lower absorber is a flat plate-like molded body that is disposed substantially parallel to a horizontal plane including the vehicle longitudinal direction and the vehicle width direction, and the side surface of the molded body on the vehicle front side and the leg portion of the pedestrian Is formed as a flat plate-like molded body installed under the bumper so as to intersect and contact. Therefore, in such a flat lower absorber, the contact area between the lower absorber and the leg of the pedestrian is inevitably reduced. As a result, it is inevitable that the weight of the lower absorber will be increased in order to obtain a high load that can be used to pay the pedestrian's legs and jump up to the bonnet even with local compression. .

  Patent Document 1 discloses a lower shock absorber (lower absorber) which is an injection molded product of a thermoplastic resin such as polypropylene or polyphenylene oxide (PPO) resin and is configured by a flat base plate along the vehicle longitudinal direction. Has been. The upper surface of the base plate is provided with a plurality of vertical ribs that extend in the vehicle front-rear direction and project at predetermined intervals, and these vertical ribs are connected to each other by horizontal ribs extending in the vehicle width direction. ing. In this way, the lower impact absorber described above is reduced in weight by being a plate-shaped molded product, and the base plate is reinforced by the vertical ribs and the horizontal ribs so that the legs of the pedestrians come into contact with the pedestrian. The rigidity necessary to pay is secured.

  However, in this lower stage shock absorber, the height of the longitudinal ribs is necessary to ensure the required rigidity, so there is a limit to reducing the weight.

  On the other hand, Patent Document 2 discloses a leg cleaning device (lower absorber) having a flat plate portion disposed so as to extend in the vehicle longitudinal direction. Two types of reinforcing beads that extend in the vehicle longitudinal direction and are alternately arranged in the vehicle width direction are integrally formed on the front portion of the plate portion. The first reinforcing bead has a U-shaped cross section that protrudes upward from the vehicle and opens downward when viewed from the front-rear direction of the vehicle, and the second reinforcing bead protrudes from the lower side of the vehicle and is viewed from the front-rear direction of the vehicle. And has a U-shaped cross section opening upward. That is, each of the first and second reinforcing beads has a rectangular wave shape in a cross section orthogonal to the vehicle longitudinal direction. With such a structure of the reinforcing bead, the above-described leg cleaning device can keep the height of the reinforcing bead low to ensure the same degree of rigidity as compared with the lower shock absorber of Patent Document 1. Thus, weight reduction is achieved.

JP 2002-274298 A JP 2007-331455 A

  However, there is still a high demand for reduction in fuel consumption of vehicles (automobiles), and further weight reduction is required. Thus, it has not been possible to achieve a sufficient weight reduction in the leg payment device of Patent Document 2. In addition, the leg washer of Patent Document 2 has a shape in which the reinforcing beads protrude upward and downward of the vehicle, so the height in the vehicle vertical direction increases, and it cannot be adopted due to vehicle space constraints. There was also a problem that there was sex.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a structure capable of ensuring a required load bearing performance even in a vehicle impact absorber such as a lower absorber even if the weight is reduced.

  In order to achieve the above-described object, a vehicle impact absorber according to the present invention is installed in a lower region in front of a vehicle such that a first direction which is a longitudinal direction is parallel to a vehicle width direction, and the vehicle A plate-like vehicle shock absorber disposed substantially parallel to a plane including a front-rear direction and a vehicle width direction, each projecting from a plate surface of the vehicle shock absorber, each of which is a first in the plate surface A plurality of reinforcing ribs extending in a second direction orthogonal to the direction of the at least one of the adjacent reinforcing ribs is formed at the end of the reinforcing rib and has a branching rib extending from the end The reinforcing ribs adjacent to each other are integrally connected to each other via the branch ribs.

  In such a vehicle impact absorber, a plurality of reinforcing ribs juxtaposed in the vehicle width direction (first direction) are connected to each other by branch ribs provided at end portions of the respective reinforcing ribs. The structure is such that the load easily propagates in the width direction. Therefore, even in the case of local compression such as a collision with a pedestrian's leg, a repulsive load can be generated from a wide range in the vehicle width direction, and the entire shock absorber can function efficiently. It becomes. Therefore, even if the weight is further reduced by reducing the plate thickness, the required load resistance performance can be ensured.

  As described above, according to the present invention, in a vehicle impact absorber such as a lower absorber, a structure capable of ensuring a required load bearing performance can be provided even if the weight is reduced.

It is a schematic perspective view which shows the lower absorber as a shock absorber for vehicles in one Embodiment of this invention. It is a schematic plan view which shows the lower absorber as a shock absorber for vehicles in one Embodiment of this invention. It is a schematic plan view which shows the modification of the reinforcement rib of the lower absorber as a shock absorber for vehicles in one Embodiment of this invention. It is a figure for demonstrating a collision analysis. It is a schematic perspective view which shows the test sample (lower absorber) of the Example used for the collision analysis. It is a schematic plan view which shows the test sample (lower absorber) of the Example used for the collision analysis. It is a schematic plan view which shows the test sample (lower absorber) of the Example used for the collision analysis. It is a schematic perspective view which shows the test sample (lower absorber) of the comparative example used for the collision analysis. It is a figure which shows the load-displacement curve of the Example and comparative example which were obtained by the collision analysis. It is a figure which shows the deformation | transformation and stress distribution of the Example and comparative example which were obtained by the collision analysis.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view schematically showing a lower absorber as a shock absorber for a vehicle in an embodiment of the present invention. 2 (a) is a schematic plan view of the lower absorber shown in FIG. 1, and FIG. 2 (b) is a partially enlarged view of the lower absorber shown in FIG. 2 (a).

  The lower absorber of the present embodiment is an elongated plate-like member having a planar shape, and is disposed in parallel to a plane (horizontal plane) including a vehicle longitudinal direction and a vehicle width direction with respect to the vehicle, and its longitudinal direction. Is assumed to be installed in parallel with the vehicle width direction. Therefore, in the following description, each direction in the plate | board surface of a lower absorber is set as each direction of the corresponding vehicle in the state installed in the vehicle. That is, as shown in FIG. 1, the longitudinal direction (first direction) of the lower absorber is a vehicle width direction W, and the direction (second direction) perpendicular to the longitudinal direction is a vehicle longitudinal direction L. Note that both the perspective view of FIG. 1 and the plan view of FIG. 2 show the lower absorber as viewed from above the vehicle.

  As shown in FIGS. 1 and 2, the lower absorber 1 of the present embodiment is formed in a plate shape, and has an elongated rectangular planar shape as a whole. The lower absorber 1 is formed by injection molding a thermoplastic resin such as polypropylene or polyethylene. In addition, as a material of the lower absorber 1, it is not limited to such a single thermoplastic resin, What added inorganic fillers and rubber components, such as a talc, to a thermoplastic resin, glass fiber, etc. Natural fibers such as synthetic fibers and cellulose fibers may be added as reinforcing fibers. Alternatively, it may be a lower absorber made of a thermosetting resin or a metal material.

  Plate-shaped flange portions 2 are respectively formed on the vehicle rear side and the vehicle width direction end portion of the lower absorber 1. A plurality of mounting holes 3 are formed in the flange portion 2. When the lower absorber 1 is installed in a vehicle, the lower absorber 1 is fixed to the vehicle body via the mounting holes 3 by a known fastening means such as a screw. Will be. Further, the flange portion 2 on the vehicle rear side is provided with a notch portion 4 according to the shape of the vehicle body to be fixed.

  In the region surrounded by the flange portion 2 of the lower absorber 1, a recessed portion 5 is formed which is one step lower than the flange portion 2 on the vehicle lower side. The recessed portion 5 is formed with a plurality of reinforcing ribs 6 projecting upward from the bottom surface of the recessed portion 5 and extending in the vehicle longitudinal direction L.

  The reinforcing ribs 6 are provided to increase the rigidity of the lower absorber 1 formed in a flat plate shape. In the present embodiment, the reinforcing ribs 6 have the same thickness and are arranged with a certain interval in the vehicle width direction W. Has been. Therefore, in this embodiment, the rigidity of the lower absorber 1 is constant in the vehicle width direction W. However, the configuration of the reinforcing rib 6 is not limited to this, and the thickness of the reinforcing rib 6 and the interval between the reinforcing ribs 6 are as follows. It can also be changed according to the position in the vehicle width direction W. That is, the rigidity of the lower absorber 1 can be gradually increased from the end in the vehicle width direction W toward the center, for example.

  Each reinforcing rib 6 of the lower absorber 1 is formed at an end portion (hereinafter referred to as “front end portion”) on the front side of the vehicle, and includes a branch rib 7 that branches in two from the end portion. As shown in FIG. 2B, the branch ribs 7 are integrally connected to the branch ribs 7 of the adjacent reinforcing ribs 6 so that their respective tips are in contact with each other. As a result, the reinforcing ribs 6 adjacent to each other in the vehicle width direction W are integrally connected to each other via the branch ribs 7 formed on each of the reinforcing ribs 6. Therefore, the plurality of reinforcing ribs 6 juxtaposed in the vehicle width direction W are Are integrally connected to each other. With such a configuration, in the lower absorber 1 of the present embodiment, the load propagation property in the vehicle width direction W is significantly improved. That is, even in the case of local compression such as contact with the legs of a pedestrian, the load is likely to propagate in the vehicle width direction W of the lower absorber 1. Therefore, the lower absorber 1 can generate a repulsive load throughout the vehicle width direction W, and the entire lower absorber 1 can efficiently exhibit load bearing performance. As a result, even if the overall weight is reduced by reducing the thickness of the lower absorber, etc., the required load-bearing performance can be ensured, so it is possible to realize a lower weight lower absorber. Become.

  Further, as shown in FIG. 2B, the branch rib 7 extends in a Y-shape from the front end portion of the reinforcing rib 6 when viewed from the vehicle upper side of the lower absorber 1. That is, the branch rib 7 branched into two from one reinforcing rib 6 is formed so as to be symmetric with respect to the direction in which the reinforcing rib 6 extends (vehicle longitudinal direction L). As a result, the branch rib 7 can also absorb the impact load when it expands and buckles under the impact load, so that the impact absorbing performance of the lower absorber 1 is improved. .

  Here, the branch rib 7 is formed so that the angle formed by the direction in which the branch rib 7 extends and the vehicle front-rear direction L is in the range of 20 ° to 60 ° when viewed from the vehicle upper side of the lower absorber 1. It is preferable that it is formed so as to be in the range of 30 ° to 50 °. If it is equal to or more than the lower limit described above, the length of the reinforcing rib 6 in the vehicle front-rear direction L becomes too short, and the leg-paying performance of the lower absorber 1 is lowered, or the interval between the reinforcing ribs 6 adjacent to each other is narrowed. Thus, an increase in the weight of the lower absorber 1 is suppressed. Moreover, if it is below the above-mentioned upper limit value, sufficient space | interval for ensuring the leg-paying performance of the lower absorber 1 will be acquired, without the space | interval between the mutually adjacent reinforcement ribs 6 becoming too wide, and the branch rib 7 The effect of improving the shock absorption performance by the is also obtained.

  In this embodiment, all the reinforcing ribs 6 (branch ribs 7) have substantially the same height as the depth of the recessed portion 5, that is, the height from the bottom surface of the recessed portion 5 to the flange portion 2. It is formed to become. However, the rib height of the reinforcing rib 6 is not limited to this, but is preferably formed so as to be lower than the height to the flange portion 2. With such a configuration, the reinforcing rib 6 itself can be protected. When the lower absorber 1 is stacked during transportation after the molding of the lower absorber 1, the reinforcing rib 6 is deformed or damaged. It is possible to reduce the risk of being lost as much as possible.

  A front side wall (transverse rib) 8 is formed at the front end of the lower absorber 1 so as to project upward from the bottom surface of the recessed portion 5 and extend in the vehicle width direction W. As shown in FIG. 2B, the front side wall 8 is integrally connected to the branch ribs 7 so as to contact the ends of the branch ribs 7 connected to each other, that is, the reinforcing ribs 6 adjacent to each other. The branch rib 7 and the front side wall 8 are connected to each other at one connection point X. Thereby, in this embodiment, it becomes possible to raise effectively the rigidity of the vehicle front side of the lower absorber 1, suppressing the increase in the weight of the lower absorber 1. FIG. Therefore, the repulsive load at the initial stage of the collision can be increased with respect to the impact load input to the front side wall 8 or the reinforcing portion 9 described later, whereby the lower absorber 1 of the present embodiment has good leg-paying performance. Will be granted. Further, the reinforcing ribs 6 juxtaposed on the upper surface side (the vehicle upper side) of the lower absorber 1 are connected to each other not only via the branch rib 7 but also via the front side wall 8. Has been. Therefore, in the present embodiment, the propagation property of the impact load locally input from the front side of the vehicle in the vehicle width direction W is further improved, thereby efficiently using the entire lower absorber 1. Thus, a repulsive load can be generated. As a result, it is possible to reduce the weight of the lower absorber 1 without significantly degrading the conventional leg-paying performance, that is, while maintaining good leg-paying performance, by significantly improving the leg-paying performance of the lower absorber. It becomes.

  Further, the front side wall 8 of the lower absorber 1 has a reinforcing wall 9a serving as an impact input surface so as to protrude from the front side wall 8 toward the front of the vehicle, and the vehicle between the front side wall 8 and the reinforcing wall 9a. A reinforcing portion 9 having a bridging rib 9b extending in the front-rear direction L is formed. The vehicle front side of the lower absorber 1 is reinforced by the reinforcing portion 9 in addition to the front side wall 8 described above, and the rigidity is increased compared with the vehicle rear side, so that the repulsive load at the initial stage of the collision is increased, and walking The leg-paying performance for the leg portion of the person is further improved.

  Note that the recessed portion 5 of the lower absorber 1 has holes for draining mainly on the bottom surfaces of the region surrounded by the adjacent reinforcing ribs 6 and the region surrounded by the branch ribs 7 and the front side wall 8. The through-hole 10 that functions as is formed. Thereby, in the lower absorber 1 of the present embodiment, the water accumulated in the above-described region of the recessed portion 5 is discharged from the through hole 10 when traveling in the rain or the like, thereby increasing the vehicle weight and deteriorating the fuel consumption. Can be suppressed. In relation to this, it is preferable that the above-described region of the recessed portion 5 is formed so as to incline downward toward the through hole 10 in order to enhance the water discharge performance.

  As mentioned above, in this embodiment, although the case where the reinforcing rib 6 (branch rib 7) was formed in the upper surface side (vehicle upper side) of the lower absorber 1 was mentioned as an example, this invention is not limited to this, The reinforcing rib may be formed on the lower surface side (the vehicle lower side) of the lower absorber. The reinforcing ribs may be formed on both the upper surface side and the lower surface side of the lower absorber. In such a lower absorber, in order to obtain the same rigidity as when the reinforcing ribs are formed only on one side, the total rib height on both sides should be lower than the rib height when only one side is formed. Can do. For this reason, it is possible to further reduce the weight of the lower absorber. Further, in the present embodiment, the branch rib 7 is formed only at the front end portion of the reinforcing rib 6, but as in the following modification, it is formed at the end portion of the reinforcing rib on the vehicle rear side or in an intermediate region. Or a plurality of reinforcing ribs may be formed on one reinforcing rib.

  FIG. 3A to FIG. 3F are schematic plan views showing modified examples in which the configuration of the reinforcing rib is changed in the lower absorber of the present embodiment, and an enlarged part of the lower absorber as viewed from the upper side of the vehicle. As shown.

  3 (a) to 3 (f), a rear side wall (transverse rib) 11 having the same configuration as that of the front side wall 8 is provided at an end of the lower absorber on the vehicle rear side (hereinafter referred to as "rear end"). A modification is shown in which a plurality of reinforcing ribs 6 are formed between them. In these modified examples, the point that each reinforcing rib 6 is formed along the vehicle front-rear direction L and the point that the branching rib 7 branches off from the end of the reinforcing rib and extends are described above. It is the same. 3A to 3F, for each branch rib 7, the angle formed by the direction in which the branch rib 7 extends and the direction in which the reinforcing rib 6 extends (vehicle longitudinal direction L) is 45 °. The case is shown. In addition, in FIG. 3 (a) to FIG.3 (f), the through-hole formed in the recessed part of a lower absorber is not shown in figure for simplicity.

  In order to improve the load propagation property in the vehicle width direction in the lower absorber and thereby reduce the weight of the lower absorber, as in the embodiment shown in FIGS. Need not be formed. That is, as shown in FIGS. 3A and 3B, at least one of the reinforcing ribs adjacent to each other includes a branching rib, and the reinforcing ribs adjacent to each other are integrally connected via the branching rib. It only has to be.

  The modification shown in FIG. 3A is a modification in which a reinforcing rib 16 having no branching ribs is added between the plurality of reinforcing ribs 6 of the embodiment shown in FIG. 2B. That is, the reinforcing ribs 6 on which the branch ribs 7 are formed and the reinforcing ribs 16 on which the branch ribs are not formed are alternately arranged in the vehicle width direction W.

  In this modification, the reinforcing ribs 6 and 16 adjacent to each other have their respective tips, that is, the front end portion of the reinforcing rib 16 where the branching rib is not formed and the tip of the branching rib 7 of the reinforcing rib 6 are mutually connected. They are connected together. Thereby, the reinforcing rib 16 in which the branch rib is not formed is integrally connected to the front side wall 8 at the connection point X where the branch rib 7 of the adjacent reinforcing rib 6 and the front side wall 8 are connected. . Therefore, the front side wall 8 is reinforced not only by the branch rib 7 but also by the reinforcing rib 16 on which the branch rib is not formed, so that its rigidity is further increased. Therefore, in this modification, it is possible to obtain an effect that the repulsive load at the initial stage of the collision is further increased with respect to the collision load input to the lower absorber.

  The modified example shown in FIG. 3B is different from the modified example shown in FIG. 3A in that one of the reinforcing ribs 6 adjacent to the reinforcing rib 16 where the branched ribs are not formed is the branched rib 7 ′. It is the modification which changed the edge part which forms A from the front-end part to the rear-end part. That is, the reinforcing ribs 16 not formed with the branch ribs are integrally connected to the front side wall 8 and the rear side wall 11 at the front end portion and the rear end portion, respectively, and the branch ribs 7 of the adjacent reinforcing ribs 6, 7 ′ is integrally connected to the tip. Therefore, in this modification, the reinforcing rib 6 in which the branch rib 7 is formed at the front end, the reinforcing rib 16 in which the branch rib is not formed, and the reinforcing rib 6 in which the branch rib 7 'is formed at the rear end. The reinforcing ribs 16 on which no branch ribs are formed are arranged in this order in the vehicle width direction W. With such a configuration, it is possible to provide a rigidity difference in the vehicle width direction W without reducing the load propagation performance in the vehicle width direction W at the front end portion of the lower absorber. Thereby, it becomes possible to improve the shock absorption performance by improving the deformation performance of the lower absorber.

  FIG. 3C shows a modification in which a branch rib 7 ′ is also formed at the rear end of each reinforcing rib 6 ′ with respect to the embodiment shown in FIG. 2B. In this case, the branch rib 7 ′ formed at the rear end portion is integrally connected to each other at the front ends in the same manner as the branch rib 7 formed at the front end portion. The rear side wall 11 is integrally connected so as to be in contact with the side wall 11. Thereby, the load propagation performance in the vehicle width direction W of the lower absorber can be further enhanced.

  FIG. 3D shows a modification in which the distance between the reinforcing ribs 6 is narrowed from the left side to the right side of the drawing, for example, with respect to the embodiment shown in FIG. With such a shape, it is possible to give a rigidity difference in the vehicle width direction W of the lower absorber, that is, it is possible to increase the rigidity of the lower absorber on the right side of the figure compared to the left side of the figure. .

  In the modification shown in FIG. 3 (e), an intermediate wall (transverse rib) 12 having the same configuration as the front side wall 8 and the rear side wall 11 is formed between the front side wall 8 and the rear side wall 11. This is a modification in which the same configuration as the lower absorber shown in FIG. 2B is arranged between the intermediate wall 12 and between the intermediate wall 12 and the rear side wall 11. In other words, the modification shown in FIG. 3E has a configuration in which two lower absorbers shown in FIG. Therefore, in this modified example, the structure capable of enhancing the load propagation performance in the vehicle width direction W, that is, the reinforcing ribs 6 adjacent to each other via the branch ribs 7, 7 ″ and the front side wall 8 or the intermediate wall 12. A plurality of configurations that integrally connect 6 ″ are formed in the vehicle longitudinal direction L. Therefore, the load propagation performance in the vehicle width direction W can be further enhanced as the entire lower absorber.

  FIG. 3F shows a modification in which the configuration of the reinforcing rib 6 disposed between the front side wall 8 and the intermediate wall 12 is changed with respect to the modification shown in FIG. In this modification, the interval between the reinforcing ribs 6 arranged between the front side wall 8 and the intermediate wall 12 is larger than the interval between the reinforcing ribs 6 ″ arranged between the intermediate wall 12 and the rear side wall 11. That is, since the reinforcing rib 6 ″ on the vehicle rear side is smaller than the reinforcing rib 6 on the vehicle front side, the rigidity of the lower absorber in the region on the vehicle rear side is larger than that on the region on the vehicle front side. It is configured to be low. As a result, the load propagation performance of the lower absorber can be improved in the region on the vehicle rear side where the load propagating less than the region on the vehicle front side, which is the load input side, and the entire lower absorber can be more efficiently It is possible to generate a repulsive load by using it.

  As described above, the lower absorber according to the present embodiment has a configuration in which a load easily propagates in the vehicle width direction. Therefore, even in a local collision such as contact with a pedestrian, a wider area is obtained. A repulsive load can be generated. For this reason, even if weight reduction is performed by reducing the plate thickness, it is possible to ensure the required load bearing performance.

(Example)
The yield load (maximum load) and load propagation of the lower absorber according to the present invention were evaluated by CAE (Computer Aided Engineering) analysis. Specifically, using the CAE analysis software LS-Dyna (registered trademark, manufactured by LSTC, USA), the impactor 21 imitating the leg of a pedestrian is caused to collide with the test sample 22 as shown in FIG. Collision analysis was performed.

  As a test sample, the lower absorber (Example) shown in FIGS. 5 to 7 and the lower absorber (Comparative Example) shown in FIG. 8 were used.

  5 is a schematic perspective view of the lower absorber according to the embodiment as viewed from above the vehicle. FIGS. 6 and 7 are schematic plan views of the lower absorber shown in FIG. 5 as viewed from above and below the vehicle, respectively. It is. FIG. 8 is a schematic perspective view of the lower absorber of the comparative example as viewed from above the vehicle.

  The lower absorber 101 in the example has substantially the same configuration as that of the above-described embodiment on the upper surface side (the vehicle upper side) and the lower surface side (the vehicle lower side) of the rectangular flat plate portion 102. Specifically, it is as follows.

  An integrated front side wall 108 that protrudes upward and downward from the vehicle is formed at the front end of the plate portion 102. A reinforcing rib 106 having the same configuration as that of the embodiment shown in FIG. 2B is formed on the upper surface side of the plate portion 102 so as to be integrally connected to the front side wall 108 (see FIG. 6). That is, the branch ribs integrally connected to the front side wall 108 so that the front ends thereof are integrally connected to the front end portion of the reinforcing rib 106 and the front ends connected to each other are in contact with the front side wall 108. 107 is formed. The reinforcing rib 106 is formed from the front end portion to the middle of the rear end portion of the plate portion 102, that is, does not reach the rear end portion of the plate portion 102. For this reason, the upper surface side of the plate portion 102 is configured so that the rigidity gradually decreases from the vehicle front side region where the branch rib 107 is formed to the vehicle rear side region of only the plate portion 102.

  On the other hand, on the lower surface side of the plate portion 102, a rear side wall 111 and an intermediate wall 112 are formed, as shown in FIG. 7, in addition to the front side wall 108 protruding also above the vehicle. A reinforcing rib 106 ′ having the same configuration as that of the embodiment shown in FIG. That is, the reinforcing rib 106 ′ on the lower surface side of the plate portion 102 has a branch rib 107 integrally connected to the intermediate wall 112 at the rear end portion in addition to the branch rib 107 integrally connected to the front side wall 108. 107 '. A plurality of auxiliary ribs 115 each extending in the vehicle front-rear direction L are formed between the intermediate wall 112 and the rear side wall 111, and the auxiliary ribs 115 pass through the intermediate wall 112 and pass through the auxiliary rib 106. It is integrally connected to the “branch rib 107 at the rear end”.

  Each of the branch ribs 107 and 107 ′ provided on the upper surface side and the lower surface side of the plate portion 102 is formed so that an angle formed with the extending direction of the reinforcing ribs 106 and 106 ′ is about 45 °.

  On the other hand, the lower absorber 201 in the comparative example has substantially the same configuration as the lower absorber described in Patent Document 2. In other words, in the comparative example, the protrusions 203 and the recesses 204 that extend in the vehicle front-rear direction L and are alternately arranged in the vehicle width direction W on the vehicle front side of the plate portion 202 are orthogonal to the vehicle front-rear direction L. The convex part 203 and the recessed part 204 in which the cross section to be formed in the rectangular wave shape are formed.

  As conditions for the collision analysis, the outer dimensions of the test sample are 600 mm in the vehicle width direction W and 270 mm in the vehicle front-rear direction L in both the example and the comparative example, while the weight of the test sample is performed with respect to the comparative example. The example was 13% lighter. Moreover, the impactor 21 used for the analysis was a cylindrical iron rigid body having a diameter of 70 mm and a mass of 7.1 g around which a urethane foam 23 having a thickness of 25 mm was wound. The impactor 21 was caused to collide with the vicinity of the center of the test sample 22 at a speed of 40 km / h (see FIG. 4), and the impactor penetration amount and the load applied to the impactor were measured. FIG. 9 shows load-displacement curves of Examples and Comparative Examples obtained by such collision analysis.

  In the examples, the maximum load was obtained up to nearly 6.0 kN despite being 13% lighter than the comparative example, and the load bearing performance (leg-paying performance) was improved compared to the comparative example. Was confirmed.

  FIG. 10 summarizes the deformation / stress distribution diagrams obtained by the collision analysis for each of the progress degrees of the deformation with respect to the example and the comparative example.

  From FIG. 10, in the embodiment, compared with the comparative example, the range of the stress distribution in the vehicle width direction W and the vehicle front-rear direction L is wide, and more load propagates in the vehicle width direction W and the vehicle front-rear direction L. I understand that. In particular, the difference between the stress distributions in the middle and late stages of deformation is large. In the comparative example, a repulsive load is generated only in the peripheral area of the collision point, whereas in the example, the load is extended to a wider range. It was confirmed that the repulsive load was generated in a wide region in the vehicle width direction W and the vehicle front-rear direction L by being propagated.

1 Lower absorber 6, 6 ', 6 ", 16 Reinforcement rib 7, 7' Branch rib 8 Front side wall 11 Rear side wall 12 Middle wall W Vehicle width direction L Vehicle front-rear direction

Claims (7)

The first direction, which is the longitudinal direction, is installed in a lower region in front of the vehicle so that the first direction is parallel to the vehicle width direction, and is disposed substantially parallel to a plane including the vehicle front-rear direction and the vehicle width direction. A plate-like vehicle shock absorber,
A plurality of reinforcing ribs protruding from a plate surface of the vehicle shock absorber, each extending in a second direction perpendicular to the first direction in the plate surface;
At least one of the reinforcing ribs adjacent to each other has a branch rib formed at an end portion of the reinforcing rib and extending branched from the end portion,
The shock absorber for a vehicle, wherein the reinforcing ribs adjacent to each other are integrally connected to each other via the branch rib. Each reinforcing rib has the branch rib,
The vehicle impact absorber according to claim 1, wherein the reinforcing ribs adjacent to each other are integrally connected to each other.   The shock absorber for a vehicle according to claim 1 or 2, wherein the respective reinforcing ribs adjacent to each other are integrally connected to each other at their tips. Projecting from the plate surface of the vehicle shock absorber and having a transverse rib extending in the first direction;
The shock absorber for a vehicle according to any one of claims 1 to 3, wherein the branch rib and the transverse rib are integrally connected to each other.   5. The vehicle shock absorber according to claim 4, wherein the branch rib and the transverse rib are integrally connected to each other such that a tip of the branch rib is in contact with the transverse rib.   6. The vehicle shock absorber according to claim 4, wherein a plurality of the transverse ribs are formed along the second direction.   The shock absorber for a vehicle according to any one of claims 1 to 6, wherein the branch rib extends in a Y shape from an end portion of the reinforcing rib.