JP4847821B2 - Shock absorber for shock absorber bumper for vehicles - Google Patents

Description

  The present invention relates to an impact absorbing material, and more particularly to an impact absorbing material for an impact absorbing bumper for a vehicle.

  The shock absorbing bumper for a vehicle plays a role of mitigating the impact and preventing the vehicle body from being damaged when the vehicle comes into contact with an external object or a pedestrian. On the other hand, in recent years, bumpers have been developed with an emphasis on pedestrian protection, and the bumpers are required to suppress damage to pedestrians as much as possible. In other words, the shock absorbing bumper is required to have a shock energy absorption property that does not cause damage to the pedestrian's leg so that it cannot be recovered even when it comes into contact with the pedestrian at a relatively high speed. Is done.

  This type of shock absorbing bumper includes, for example, a bumper beam 101 that is disposed at the front of the vehicle body and extends in the vehicle width direction as shown in a cross section in FIG. 9, and a front surface 101 a of the bumper beam 101 along the vehicle width direction. The shock absorbing material 102 disposed on the bumper face 103 and the bumper face 103 covering the shock absorbing material 102 are mainly formed. The shock absorbing material 102 is formed of a foamed resin such as polypropylene, and the bumper face 103 is formed of a resin such as polyurethane or polypropylene.

  Here, the deformation resistance against the impact of the shock absorbing material 102 made of foamed resin such as polypropylene is substantially determined by the foaming ratio of the foamed resin and the deformation stroke amount of the shock absorbing material 102, particularly when the foaming ratio of the foamed resin is low. The initial drag tends to rise rapidly and become excessive. However, the expansion ratio of the foamed resin is limited by productivity and marketability, and the desired required deformation resistance characteristic may not be obtained.

  For example, even if a foamed resin having the maximum expansion ratio that can be produced is used as the shock absorbing material 102, the deformation resistance is high, the initial resistance rises rapidly and becomes excessive, and the desired required impact energy absorbability cannot be achieved. The person's legs may not be adequately protected. The deformation drag characteristic, that is, the correlation between the deformation drag and the deformation stroke is shown by a broken line ra in the “deformation drag-deformation stroke correlation diagram” shown in FIG.

  As a countermeasure against this, as shown in FIG. 10, in an impact absorbing bumper 110 in which an impact absorbing material 113 formed of foamed resin such as polypropylene is disposed between a bumper beam 111 and a bumper face 112 extending in the vehicle width direction. A plurality of groove-like recesses 115 and protrusions 116 that are continuous in the vehicle width direction are alternately formed on the rear surface 114 of the shock absorber 113 that is in contact with the front surface 111a of the bumper beam 111 so as to come into contact with an object or a leg of a pedestrian. At the same time, it is known that the projecting portion 116 is compressed or buckled by the impact load P to suppress a sudden rise and increase in initial drag (see, for example, Patent Document 1).

JP 2004-82957 A

  According to the above-mentioned Patent Document 1, even when the foaming ratio of the foamed resin is relatively low, when it comes into contact with an object or a leg of a pedestrian, the protrusion that abuts against the bumper beam 111 of the shock absorber 113 due to the impact load P. By compressing and deforming the portion 116, it is possible to suppress a sudden rise and increase in initial drag.

  However, since the protruding portion 116 is formed in a thin wall shape continuous in the vehicle width direction, in the process of the compressing deformation of the protruding portion 116 due to the impact load P due to contact with an object or a pedestrian, for example, an imaginary line in FIG. As indicated by 116a, there is a concern about the occurrence of buckling deformation such as opening and folding. When buckling deformation occurs in the process of compressive deformation of the protrusion 116, as shown by a one-dot chain line rb in FIG. Therefore, there is a concern that the object and the leg of the pedestrian cannot be sufficiently protected and a situation in which damage is caused is induced.

  Accordingly, an object of the present invention made in view of such a point is to provide a shock absorbing material for a shock absorbing bumper for a vehicle, which can obtain excellent shock energy absorption without causing damage when contacting an object or a pedestrian. There is to do.

The invention of a shock absorber for a vehicle shock absorbing bumper according to claim 1, which achieves the above object, is disposed extending in the vehicle width direction between a front surface of the bumper beam extending in the vehicle width direction and the bumper face. In the shock absorbing material made of foamed resin, the shock absorbing material extends in the vehicle width direction with a substantially rectangular cross-sectional shape having a front surface, an upper surface, a lower surface, and a rear surface in contact with the front surface of the bumper beam covered by the bumper face. A plurality of first central axes that are formed in a block shape and extend in the longitudinal direction of the vehicle body at intervals on an upper reference line that extends in the vehicle width direction along the extending direction of the shock absorber. A plurality of first holes extending in the front-rear direction of the vehicle body at intervals on a bottomed hole-like first hole extending to open to the rear surface and a lower reference line extending in the vehicle width direction below the upper reference line 2 Center axis A blind hole-shaped second air hole opened in the rear surface and extends in the vehicle longitudinal direction is formed as, by the formation of the first holes and the second holes, the upper surface to one side An upper protrusion adjacent to the first hole, an intermediate protrusion adjacent to the first hole and the second hole, and a lower protrusion adjacent to the second hole with the lower surface on one side. An upper partition protrusion connecting the upper protrusion and the intermediate protrusion, and a lower partition protrusion connecting the lower protrusion and the intermediate protrusion, and the upper partition protrusion; the lower partition wall projecting portions are arranged alternately offset in the vehicle width direction to each other, said first holes and the second holes are each in the cross-sectional shape perpendicular to the first central axis and second central axis A widened portion having a relatively wide width in the vertical direction at the center and a vehicle extending from the widened portion while continuing to the widened portion. Has a narrow portion vertical width becomes gradually narrower with increasing distance in the direction, at least a portion of the narrow portion of the narrow portion and the second cavity of the first holes overlap in the vehicle width direction to each other It is characterized by that.

  According to the present invention, even when the shock absorbing material is made of, for example, a foamed resin having a relatively low foaming ratio, the deformation drag is suppressed by the arrangement of the first hole and the second hole, so that the vehicle can walk outside objects and walks. The increase in initial deformation resistance upon contact with a person is moderate and the maximum value of deformation resistance is suppressed.

  Further, an upper protrusion that continues in the vehicle width direction between each first hole and the upper surface, and an intermediate protrusion that continues in the vehicle width direction between the first hole and each second hole are adjacent to each other. Each of the first protrusions connected by upper partition protrusions formed between the first holes and the lower protrusions and the intermediate protrusions that are continuous in the vehicle width direction between the second holes and the lower surface are adjacent to each other. Are connected by the lower partition wall protrusion formed between the two holes to prevent buckling deformation of each protrusion, ensure smooth compressive deformation and obtain good impact energy absorption, and external objects And damage to objects and pedestrians when contacted with pedestrians.

Further, each first hole and each second hole are offset from each other in the vehicle width direction, and at least a part of the narrow portion of the adjacent first hole and the narrow portion of the second hole is in the vehicle width direction. Therefore, the difference in deformation drag of each part in the vehicle width direction is suppressed, and a uniform deformation drag can be ensured over the entire width in the vehicle width direction.

The invention according to claim 2, in the impact absorbing member for a vehicle shock absorbing bumper according to claim 1, the distance in the vehicle width direction adjacent said first central axis and second central axis, the compression applied to the shock absorber The compression test apparatus is characterized in that it is set smaller than the outer diameter of a cylindrical impactor having an outer diameter assuming the size of a human shin.

  According to the present invention, by setting the distance between the first central axis and the second central axis in the vehicle width direction to be smaller than the outer diameter of the impactor, the difference in deformation drag against the impactor of each part in the vehicle width direction is suppressed. The variation in deformation resistance of each part in the vehicle width direction can be suppressed. That is, since the outer diameter of the impactor is set on the assumption of the size of a human shin, a stable deformation resistance characteristic with respect to the leg portion can be secured at each portion of the shock absorbing material in the vehicle width direction, so that the pedestrian leg portion can be secured. Damage to the can be suppressed.

  According to the shock absorbing material of the vehicle shock absorbing bumper of the present invention, the first deformation force and the second hole arranged in the shock absorbing material increase the initial deformation drag when contacting an object or a pedestrian. In addition, the maximum value of the deformation resistance is suppressed, the buckling deformation of the shock absorbing material is prevented, and a smooth compressive deformation can be secured, so that a good shock energy absorption property can be obtained.

Further, each first hole and each second hole are offset from each other in the vehicle width direction, and at least a part of the narrow portion of the adjacent first hole and the narrow portion of the second hole is in the vehicle width direction. Therefore, the difference in deformation drag of each part in the vehicle width direction is suppressed, and a uniform deformation drag can be ensured over the entire width in the vehicle width direction.

( Reference example )
Hereinafter, a reference example of a shock absorbing material for a vehicle shock absorbing bumper according to the present invention will be described with reference to FIGS. In each figure, an arrow F indicates the vehicle front direction, and an arrow W indicates the vehicle width direction.

  FIG. 1 is a cross-sectional perspective view showing a main part of an outline of a shock absorbing bumper 1 for a vehicle. The shock absorbing bumper 1 is disposed at the front of the vehicle body and extends in the vehicle width direction along the bumper beam 2 that extends in the vehicle width direction, the bumper face 5 that forms the outer surface of the bumper 1, and the front surface 3 of the bumper beam 2. And an impact absorbing material 10 which is covered by the bumper face 5.

  The bumper beam 2 has a substantially hollow rectangular cross-sectional shape and extends in the vehicle width direction. Both ends of the bumper beam 2 are supported by brackets at the front ends of vehicle body frames such as left and right side members extending in the vehicle longitudinal direction (not shown). The bumper beam 2 is formed of a steel plate or the like having excellent rigidity, and the front surface 3 is formed in a substantially rectangular shape that is long in the vehicle width direction. The bumper face 5 is formed of a resin such as polyurethane or polypropylene, and the impact absorbing material 10 is formed of a foamed resin such as polypropylene having a relatively low expansion ratio that is excellent in productivity and ensures product shape accuracy.

  The shock absorber 10 has a substantially rectangular cross-sectional shape having a front surface 11, an upper surface 12, a lower surface 13 and a rear surface 14 in contact with the front surface 3 of the bumper beam 2 covered by the bumper face 5, and extends in the vehicle width direction. The front surface 11, the upper surface 12, the lower surface 13, and the rear surface 14 are formed in a substantially rectangular shape that is long in the vehicle width direction.

  The shock absorber 10 will be described in detail with reference to FIGS. 2 is a partially enlarged view of the rear surface 14 of the shock absorber 10 that contacts the front surface 3 of the bumper beam 2. FIG. 3 is a cross-sectional view taken along line II in FIG. 2, and FIG. 4 is a line II-II in FIG. It is sectional drawing. In FIG. 3 and FIG. 4, the bumper beam 2 is indicated by a virtual line.

  The shock absorber 10 extends in the vehicle longitudinal direction on the upper reference line L1 extending in the vehicle width direction along the extending direction, with the first central axis 19a extending in the vehicle longitudinal direction at equal intervals as the axis. Then, a plurality of bottomed hole-like first holes 15 that open to the rear surface 14 and whose front surface 11 side is closed by the bottom portion 15a are arranged at equal intervals in the vehicle width direction.

  Similarly, on the lower reference line L2 extending in the vehicle width direction below the upper reference line L1, the rear center surface extends in the vehicle longitudinal direction with the second central axis 19b extending in the vehicle longitudinal direction at equal intervals as the axis. 14 and a plurality of second holes 16 having a bottomed hole shape whose front surface 11 side is closed by a bottom portion 16a are arranged at equal intervals in the vehicle width direction.

  The first center axis 19a on the upper reference line L1 and the second center axis 19b on the lower reference line L2 are alternately arranged offset in the vehicle width direction, and each first hole 15 and each second hole are arranged. The holes 16 are alternately arranged offset in the vehicle width direction. That is, the first holes 15 and the second holes 16 are alternately arranged over the entire width of the shock absorber 10 in the vehicle width direction.

  A plurality of first holes 15 are arranged at equal intervals on the upper reference line L1, and a plurality of second holes 16 are arranged at equal intervals on the lower reference line L2, so that each first hole A front surface portion 20 is formed between the bottom portions 15 a and 16 a of the holes 15 and the second holes 16 and the front surface 11. Further, an upper protruding portion 21 that is continuous in the vehicle width direction is formed between each first hole 15 and the upper surface 12, and between each first hole 15 and each second hole 16 in the vehicle width direction. A continuous intermediate protrusion 22 is formed, and a lower protrusion 23 continuous in the vehicle width direction is formed between each second hole 16 and the lower surface 13. Further, the upper protruding portion 21 and the intermediate protruding portion 22 are connected at equal intervals by the upper partition protruding portion 24 formed between the adjacent first holes 15, and similarly between the adjacent second holes 16. The intermediate projecting portion 22 and the lower projecting portion 23 are connected at equal intervals by the lower partition wall projecting portion 25.

  Further, the first holes 15 arranged on the upper reference line L1 and the second holes 16 arranged on the lower reference line L2 are alternately arranged with an offset in the vehicle width direction. Thus, the upper partition wall projections 24 formed between the adjacent first holes 15 and the lower partition wall projections 25 formed between the adjacent second holes 16 are alternately arranged in the vehicle width direction. Be placed. That is, each of the upper partition wall projections 24 and the lower partition wall projections 25 are arranged offset from each other in the vehicle width direction, and the first holes 15 and the second holes 16 overlap each other in the vehicle width direction. Formed.

  The shock absorber 10 in which the first holes 15 and the second holes 16 are alternately arranged in the vehicle width direction is made of, for example, a vapor-type foaming agent using a resin such as polypropylene resin in advance. The impregnated resin foam particles are produced, and the resin foam particles can be produced by an existing molding method such as an in-mold foaming method in which the resin foam particles are filled in a mold and heated by steam to fuse the particles.

  As shown in FIG. 1, the shock absorber 10 formed in this way is disposed in the vehicle width direction along the front surface 3 of the bumper beam 2 with the rear surface 14 coming into contact with the front surface 3 of the bumper beam 2. 12 and the lower surface 13 are covered with a bumper face 5 and disposed between the bumper beam 2 and the bumper face 5.

  Next, the operation of the shock absorbing bumper 1 configured as described above will be described.

  When a vehicle equipped with the impact bumper 1 comes into contact with an external object or a pedestrian, for example, a pedestrian's leg, and an impact load P is applied to the bumper 1 from the front, the impact is applied from the front surface 11 via the bumper face 5. A compressive load is input to the absorbent material 10. When a compressive load is input and the shock absorber 10 is compressed in the front-rear direction, the upper protruding portion 21, the intermediate protruding portion 22, the lower protruding portion 23 formed by the first hole 15 and the second hole 16, Since the deformation resistance of each protrusion of the upper partition wall protrusion 24 and the lower partition wall protrusion 25 is set lower than the deformation resistance of the front surface portion 20, the upper protrusion 21, the intermediate protrusion 22, and the lower side are mainly used. The protruding portion 23, the upper partition wall protruding portion 24, and the lower partition wall protruding portion 25 are compressed and deformed, and deformation resistance is generated along with the compressive deformation.

  Deformation drag and deformation stroke due to compressive deformation of the upper projection 21, intermediate projection 22, lower projection 23, upper partition projection 24, lower partition projection 25, and the like are shown by a solid line r in FIG. The deformation drag r gradually increases with the deformation stroke, but the deformation drag r is set low by the formation of the first hole 15 and the second hole 16, and the increase of the deformation drag r in the initial contact is moderate. In addition, the maximum value rm of the deformation drag r is suppressed and an increase in the deformation stroke is obtained, and good impact energy absorption is ensured, so that damage to the pedestrian's legs can be greatly reduced.

  When the upper projecting portion 21, the intermediate projecting portion 22, the lower projecting portion 23, the upper partition projecting portion 24, the lower partition projecting portion 25 and the like are compressed and deformed, the upper projecting portion 21 and the intermediate projecting portion extending in the vehicle width direction. 22 are connected at equal intervals by a plurality of upper partition wall projections 24 extending in the vertical direction, and the intermediate projection portion 22 and the lower projection 23 are equally spaced by a plurality of lower partition wall projections 25 extending in the vertical direction. Because of the connection at the upper projection 21, the intermediate projection 22, the lower projection 23, the upper partition projection 24, the lower partition projection 25, etc. Is restrained, a smooth and stable deformation resistance characteristic can be ensured and good impact energy absorption can be obtained, and damage to the pedestrian's legs can be suppressed.

  Further, by arranging the first holes 15 and the second holes 16 alternately in the vehicle width direction, variation in deformation resistance of each portion of the shock absorber 10 in the vehicle width direction is suppressed. In other words, the difference in deformation resistance in each part in the vehicle width direction can be reduced, and a uniform deformation resistance can be secured over the entire width in the vehicle width direction, and reduction of damage to the legs of the pedestrian can be expected.

( First embodiment)
Hereinafter, a first embodiment of a shock absorbing material for a vehicle shock absorbing bumper according to the present invention will be described with reference to FIG. In FIG. 6, parts corresponding to those in FIGS. 1 to 4 are denoted by the same reference numerals, detailed description thereof will be omitted, and different parts will be mainly described. FIG. 6 is an enlarged rear view of the shock absorber 10 corresponding to FIG.

  The shock absorber 10 extends on the upper reference line L1 extending in the vehicle width direction along the extending direction thereof, and extends in the front-rear direction around the first central axis 19a extending in the vehicle body front-rear direction, and is opened on the rear surface 14. The bottomed hole-shaped first holes 15 are arranged in a plurality of rows at equal intervals in the vehicle width direction and extend in the front-rear direction about the second center axis 19b extending in the vehicle body front-rear direction on the lower reference line L2. Then, a plurality of bottomed hole-like second holes 16 opened in the rear surface 14 are arranged at equal intervals in the vehicle width direction.

  The first hole 15 has, in a cross-sectional shape orthogonal to the first center axis 19a, linear upper and lower edges 15c and 15d that extend in the vehicle width direction and face each other via the first center line 19a. 15c and a lower edge 15d are substantially oval having arcuate side edges 15e connecting the ends of the lower edge 15d, and the upper edge 15c and the lower edge 15d have a wide portion 15A having a relatively wide vertical width at the center. A narrow portion 15B is formed which is formed and is continuous with the widened portion 15A by each side edge 15e and gradually decreases in width in the vertical direction as it moves toward the end portion 15f away from the first central axis 19a.

  Similarly, the second hole 16 has a linear upper edge 16c and a lower edge 16d that extend in the vehicle width direction and face each other via the second central axis 19b in a cross-sectional shape orthogonal to the second central axis 19b. The upper edge 16c and the lower edge 16d are substantially oval having arc-shaped side edges 16e that connect the ends of the lower edge 16d, and the upper edge 16c and the lower edge 16d have a relatively wide vertical width at the center. A widened portion 16A is formed, and a narrow width portion 16B is formed which is continuous with the widened portion 16A by each side edge 16e and gradually decreases in width in the vertical direction as it moves toward the end portion 16f away from the central axis 19b.

  The first central axis 19a arranged on the upper reference line L1 and the second central axis 19b on the lower reference line L2 are offset from each other in the vehicle width direction, and the narrow portion 15B of the first hole 15 and the first At least a part of the narrow portion 16B of the two holes 16 is wrapped in the vehicle width direction, that is, overlapped. By arranging an overlapping range L3 between the narrow portion 15B of the first hole 15 and the narrow portion 16B of the second hole 16, an upper protrusion 21 and an intermediate protrusion 22 in each longitudinal section in the vehicle width direction. Further, the variation in the total area of the protrusions of the lower protrusion 23, the upper partition protrusion 24, and the lower partition protrusion 25 is suppressed. For example, the upper protruding portion 21, the intermediate protruding portion 22, the lower protruding portion 23, the upper partition protruding portion 24, the occupied area of the lower partition protruding portion 25 and the upper protruding portion 21 in the IV-IV line section in the III-III line section, Differences in the occupied areas of the intermediate projecting portion 22, the lower projecting portion 23, the upper partition projecting portion 24, and the lower partition projecting portion 25 are suppressed, and variation in deformation resistance of each portion in the vehicle width direction can be suppressed. In other words, in addition to the first embodiment, the deformation resistance difference in the vehicle width direction is further suppressed, and a uniform deformation resistance can be secured over the entire width in the vehicle width direction, and the reduction of damage to the pedestrian's legs can be expected. .

  Note that the cross-sectional shapes of the first hole 15 and the second hole 16 are not limited to the shape shown in FIG. In addition, the cross-sectional shape can be changed to another cross-sectional shape having a narrowed portion that gradually narrows from the widened portion in the vehicle width direction, for example, a circle, an ellipse, or a rhombus.

( Second Embodiment)
A second embodiment of the shock absorbing material for a vehicle shock absorbing bumper according to the present invention will be described below with reference to FIGS. 7 and 8 as reference examples . 7 and 8, the same reference numerals are given to the portions corresponding to those in FIGS. 1 to 4, and the detailed description thereof is omitted.

  FIG. 7 is a partially enlarged view of the rear surface 14 of the shock absorber 10 that abuts against the front surface 3 of the bumper beam 2 corresponding to FIG. 2, and the shock absorber 10 has a vehicle width direction along its extending direction. A bottomed hole-like first hole 15 extending in the vehicle front-rear direction with the first central axis 19a extending in the vehicle body front-rear direction as an axis is opened on the upper reference line L1 extending in the vehicle width direction. A plurality of second holes having a bottomed hole that are provided in a plurality of rows at equal intervals and extend in the longitudinal direction of the vehicle body with the second central axis 19b extending in the longitudinal direction of the vehicle body on the lower reference line L2 and opening in the rear surface 14 extending in the longitudinal direction of the vehicle body. A plurality of holes 16 are provided at equal intervals in the vehicle width direction. The first center axis 19a arranged on the upper reference line L1 and the second center axis 19b arranged on the lower reference line L2 are alternately arranged in the vehicle width direction and are alternately arranged. One hole 15 and each second hole 16 are alternately arranged in the vehicle width direction.

  A compression test for inspecting the deformation resistance characteristic of the shock absorber 10 will be described with reference to FIG. 8A is a side view of the test apparatus 50, and FIG. 8B is a plan view.

  The compression test method is performed by compressing the impact absorbing material 10 at a preset test speed using an impactor made of a rigid pipe as a compression jig under conditions of preset temperature and relative humidity. The outer diameter D of the impactor 51 assumes the size of a human shin.

  In FIG. 8, 10 is an impact absorbing material to be a test piece, 51 is an impactor made of a rigid pipe having an outer diameter D of 70 mm, 52 is a holding base for a test piece made of a rigid body extending in the horizontal direction, 53 Is a compression device to which the impactor 51 is attached.

  The support base 52 is installed extending in the horizontal direction assuming the height of the bumper beam 2 of the bumper 1 mounted on the vehicle. The shock absorbing material 10 serving as a test piece is installed with the rear surface 14 facing the front surface 52a of the support base 52 and extending in the horizontal direction. The compression device 53 assumes a case where the bumper 1 mounted on the vehicle comes into contact with a pedestrian, that is, a standing human leg, from the front surface 11 side of the shock absorber 10 as shown in FIGS. As shown in FIG. 3, the impactor 51 is moved in the front-rear direction from the front surface 11 side so that the axial direction of the impactor 51 is perpendicular to the length direction (vehicle width direction) of the shock absorber 10 (ie, the vehicle width direction). Apply compression and perform compression test.

  Each shock absorber 10 is subjected to a compression test until a compression strain set in advance, for example, 70% or more, that is, a deformation stroke is generated, and a compression load at each deformation stroke, that is, a deformation drag is measured from a compression curve. To do.

  Here, an interval L4 between the first central axis 19a serving as the axis of each first hole 15 and the second center axis 19b serving as the axis of the second hole 16 in the vehicle width direction is determined from the outer diameter D of the impactor 51. By setting small (L4 <D), the upper protrusion 21, the intermediate protrusion 22, the lower protrusion 23, the upper partition protrusion 24, the lower side by the impactor 51 in each part in the longitudinal direction of the shock absorbing member 10 Variations in the projected area of the partition protrusion 25 are suppressed. Thereby, the difference of the deformation drag in each part of the vehicle width direction with respect to the impactor 51 is suppressed, and the variation in the deformation drag of each part in the vehicle width direction can be suppressed. In other words, since the outer diameter D of the impactor 51 is set on the assumption of the size of a human shin, stable deformation resistance characteristics can be secured and damage to the pedestrian's legs can be suppressed.

Similarly, the cross-sectional shape of the first hole 15 and the second hole 16 in the first embodiment has a widened portion with a relatively wide vertical width at the center, and is continuous with the widened portion and the widened portion. By forming a shape having a narrow width portion that gradually narrows from the vehicle width direction to the vehicle width direction, the deformation resistance difference in each portion in the vehicle width direction is further suppressed, and a uniform deformation drag can be secured over the entire width in the vehicle width direction. Reduction of damage to pedestrian legs can be expected.

It is a principal part section perspective view showing an outline of a shock absorption bumper for vehicles concerning a reference example of the present invention. It is a partially expanded view of the rear surface of the shock absorber. It is the II sectional view taken on the line of FIG. It is the II-II sectional view taken on the line of FIG. It is a deformation drag-deformation stroke correlation diagram. 1 is a partially enlarged view of a rear surface of a shock absorber showing an outline of a vehicle shock absorber bumper according to a first embodiment of the present invention. It is a reference figure explaining the shock absorbing bumper for vehicles concerning a 2nd embodiment of the present invention, and is a partial enlarged view of the rear surface of a shock absorbing material. It is explanatory drawing which shows the outline | summary of the compression test method of an impact-absorbing material, (a) is a side view of a compression test apparatus, (b) is a top view. It is sectional drawing of the conventional impact-absorbing bumper. It is sectional drawing of the conventional impact-absorbing bumper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle shock absorption bumper 2 Bumper beam 3 Front surface 5 Bumper face 10 Shock absorber 11 Front surface 12 Upper surface 13 Lower surface 14 Rear surface 15 1st hole 15A Wide part 15B Narrow part 16 2nd hole 16A Wide part 16B Narrow part 19a First central axis 19b Second central axis 20 Front surface 21 Upper protrusion 22 Intermediate protrusion 23 Lower protrusion 24 Upper partition protrusion 25 Lower partition protrusion 50 Test device 51 Impactor 53 Compressor D Impactor diameter L1 Upper Reference line L2 Lower reference line L3 Overlapping range L4 Spacing in the vehicle width direction between the first central axis and the second central axis

Claims (2)

In the shock absorber made of a foamed resin that extends in the vehicle width direction between the front surface of the bumper beam extending in the vehicle width direction and the bumper face,
The shock absorber is formed in a block shape extending in the vehicle width direction in a substantially rectangular cross-sectional shape having a front surface, an upper surface, a lower surface and a rear surface in contact with the front surface of the bumper beam, which are covered by the bumper face.
The rear surface extends in the vehicle front-rear direction with a plurality of first central axes extending in the vehicle front-rear direction at intervals on an upper reference line extending in the vehicle width direction along the extension direction of the shock absorber. A first hole with a bottomed hole opening in
A plurality of second central axes extending in the longitudinal direction of the vehicle body at intervals on a lower reference line extending in the vehicle width direction below the upper reference line extend in the longitudinal direction of the vehicle body and open to the rear surface. A bottomed hole-like second hole is formed,
Due to the formation of the first hole and the second hole, the upper protrusion is adjacent to the first hole with the upper surface on one side, and the first hole and the second hole are adjacent to each other. An intermediate protrusion, a lower protrusion adjacent to the second hole with the lower surface on one side, an upper partition protrusion connecting the upper protrusion and the intermediate protrusion, and the lower protrusion A lower bulkhead projection connecting the middle projection ,
The the upper partition wall projection and the lower partition wall projecting portions are arranged alternately offset in the vehicle width direction to each other,
The first hole and the second hole are continuous with the widened portion having a relatively wide vertical width at the center and the widened portion in a cross-sectional shape orthogonal to the first central axis and the second central axis, respectively. Having a narrow width portion in which the width in the vertical direction gradually narrows as the distance from the wide width portion increases in the vehicle width direction,
An impact-absorbing material for a vehicle impact-absorbing bumper, wherein at least a part of the narrow portion of the first hole and the narrow portion of the second hole overlap each other in the vehicle width direction . A cylindrical impactor having an outer diameter in which the distance between the adjacent first central axis and the second central axis in the vehicle width direction assumes the size of a human shin in a compression test apparatus that compresses and applies the shock absorber. 2. The shock absorbing material for a vehicle shock absorbing bumper according to claim 1 , wherein the shock absorbing material is set smaller than an outer diameter.

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