JP2014004973A - Crash box for vehicle and bumper device for vehicle and impact absorption structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crash box for a vehicle capable of sufficiently performing weight saving while ensuring excellent impact absorption performance, and easily tuning an impact absorption characteristic.SOLUTION: A cylindrical resin molding 10 includes a honeycomb structure in which a plurality of cylindrical cells 12 with the area of a cross section perpendicular to a hexagonal axis gradually increasing toward one side in an axial direction share at least one side 14 and are arranged mutually adjacently, and a through hole 20 for adjusting strength to plastic deformation in an axial direction is formed in the cylindrical resin molding 10.

Description

  The present invention relates to a vehicular crash box, a vehicular bumper device, and an impact absorbing structure for a vehicle, and more particularly, an improved vehicle that can advantageously absorb energy of impact input via a bumper reinforcement. The present invention relates to a crash box for a vehicle, a bumper device for a vehicle, and a shock absorbing structure for the vehicle.

  Generally, a bumper device is installed in a front part and a rear part of a vehicle such as an automobile. This bumper device includes, for example, a bumper reinforcement and a bumper reinforcement that are arranged to extend in the vehicle width direction at the front and rear parts of a vehicle, as disclosed in Japanese Patent Application Laid-Open No. 2009-56945. At both ends, between the bumper reinforcement and the pair of side members extending in the vehicle front-rear direction, a pair of cylindrical crash boxes are provided so as to extend in the vehicle front-rear direction. . Many bumper devices also include a bumper cover that is located on the opposite side of the bumper reinforcement from the side where the crash box is disposed. In such a bumper device, for example, at the time of a vehicle collision, a pair of crash boxes are continuously plastically deformed in a bellows shape in the axial direction due to an impact load input via a bumper reinforcement. By doing so, it is configured to be able to absorb impact energy. In this way, the vehicle body and passengers can be protected.

  However, a crush box constituting such a conventional bumper device is usually formed using a metal material such as iron. For this reason, there is a drawback that the weight is large. In addition, many of such crash boxes are composed of a rectangular tube having a constant cross-sectional area perpendicular to the axis. Therefore, in such a conventional crash box, when the impact load is input from the direction intersecting (inclining direction) with respect to the axial direction, there is a risk of being pushed sideways. And when it laid down like that, there was a possibility that a sufficient deformation stroke could not be secured and the amount of shock energy absorbed would be insufficient.

  In addition, in the conventional crash box, for example, the strength against plastic deformation can be increased by changing the size and overall shape of the cylindrical wall portion or the like, or the type of metal material used as a forming material. It was supposed to be adjusted. Therefore, in such a conventional crash box, it is inevitable that the tuning of the shock absorption characteristic becomes complicated.

  In order to reduce the weight of the crash box, it is conceivable to change the metal crash box to a resin. However, the resin crash box has an extremely low strength against plastic deformation than the metal crash box. Therefore, if the crash box is simply made of resin, it will not be able to secure the same amount of shock absorption as a conventional metal crash box. As a result, there is a problem that the remarkably decreases.

JP 2009-56945 A

  Here, the present invention has been made in the background of the above-mentioned circumstances, and the place to solve the problem is to effectively secure the same impact absorption performance as a metal crash box, Sufficient weight reduction can be achieved advantageously, and the impact absorption performance equivalent to that of a conventional bumper device with a crash box for vehicles that can easily tune shock absorption characteristics and a metal crash box is effective. In addition to ensuring a sufficient weight reduction, the bumper device that can easily tune the shock absorption characteristics and the shock absorption performance equivalent to the conventional shock absorption structure are effectively secured. On the other hand, an object of the present invention is to provide a shock absorbing structure for a vehicle that can advantageously achieve weight reduction of the entire vehicle and that can easily tune shock absorbing characteristics.

  In order to solve the above problems, the present invention provides a bumper reinforcement that extends in the vehicle width direction and a side member that is spaced from the bumper reinforcement in the vehicle front-rear direction. A crash box for a vehicle, which is made of a cylindrical body that is interposed so as to extend in the vehicle front-rear direction and absorbs impact energy by plastic deformation in the axial direction by an impact load input through the bumper reinforcement. A plurality of cylindrical cells having a hexagonal cross section in the direction perpendicular to the axis and the area of the cross section in the direction perpendicular to the axis gradually increasing toward one side in the axial direction share at least one side and are adjacent to each other. And a through hole for adjusting the strength against plastic deformation in the axial direction of the cylindrical resin molded body. Is formed, a vehicle crash box, characterized in that it is configured, it is an gist thereof.

  The present invention also includes a bumper reinforcement that extends in the vehicle width direction, a pair of side members that are spaced from the bumper reinforcement in the vehicle front-rear direction, and both ends of the bumper reinforcement. A vehicle bumper device characterized in that it includes a vehicle crash box having the above-described characteristics, which are interposed between them, is also the gist thereof.

  Furthermore, the present invention provides the above-described feature between the both end portions of the bumper reinforcement extending in the vehicle width direction and the pair of side members that are spaced from the bumper reinforcement in the vehicle front-rear direction. The vehicle crash box is interposed, and the vehicle crash box is plastically deformed in the axial direction by an impact load input via the bumper reinforcement, so that the impact energy is absorbed. The impact absorbing structure for a vehicle characterized by the above is also the gist thereof.

  That is, in the vehicle crash box according to the present invention, a sufficient weight reduction can be achieved by being constituted by the cylindrical resin molded body. In addition, since the cylindrical resin molded body is configured with a honeycomb structure in which a plurality of cylindrical cells share at least one side and are arranged adjacent to each other, compared to a resin molded body made of a simple cylindrical body. Thus, the strength against axial plastic deformation can be dramatically increased.

  Furthermore, in the crash box for a vehicle according to the present invention, a through hole for adjusting the strength against plastic deformation in the axial direction is formed. For this reason, in such a crash box for a vehicle, for example, simply through-holes without changing the size such as the thickness of the cylindrical cell, the overall basic shape, or the type of the forming material in a complex manner. The strength against plastic deformation in the axial direction can be adjusted simply by changing the size and the forming position.

  Moreover, in the vehicle crash box according to the present invention, the cross-sectional area in the direction perpendicular to the axis of each of the plurality of cylindrical cells gradually increases toward one side in the axial direction. Thereby, the entire crash box has a shape that extends outward in the direction perpendicular to the axis from one end side in the axial direction toward the other end side. Therefore, unlike a conventional vehicle crash box in which the cross-sectional area perpendicular to the axis is constant in the axial direction, such a vehicle crash box is input from the direction in which the impact load intersects the crash box axial direction. When this is done, it can be effectively prevented or suppressed that the battery is easily laid down and the amount of plastic deformation in the axial direction becomes insufficient.

  Therefore, in the vehicle crash box according to the present invention as described above, it is possible to advantageously achieve a sufficient weight reduction while effectively ensuring the same level of shock absorption performance as a metal crash box, In addition, the shock absorption characteristics can be easily tuned.

  The vehicle bumper device according to the present invention has the same crash absorption as the conventional bumper device having a metal crash box by having the vehicle crash box exhibiting the excellent characteristics as described above. A sufficient weight reduction can be advantageously realized while effectively securing the performance, and the shock absorption characteristics can be easily tuned.

  Further, even in the shock absorbing structure for a vehicle according to the present invention, the impact absorbing performance equivalent to that of the conventional shock absorbing structure can be obtained by using the vehicle crash box that exhibits the excellent characteristics as described above. Thus, it is possible to advantageously reduce the weight of the entire vehicle while ensuring the safety of the vehicle, and to easily tune the shock absorption characteristics.

It is front explanatory drawing which shows one Embodiment of the crash box for vehicles which has a structure according to this invention. It is II-II sectional explanatory drawing of FIG. It is explanatory drawing which shows the state which attached the crash box for vehicles shown by FIG. 1 to the front part of the vehicle. 2 is a graph showing a load-displacement characteristic of the vehicle crash box shown in FIG. 1 and a load-displacement characteristic of a vehicle crash box having a conventional structure. It is a figure corresponding to FIG. 1 which shows another embodiment of the crash box for vehicles which has a structure according to this invention. It is VI-VI cross-section explanatory drawing of FIG.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, in FIG. 1 and FIG. 2, as an embodiment of a crash box for a vehicle having a structure according to the present invention, a crash box for an automobile constituting a bumper device installed at the front part of the automobile has a front form and a shaft. They are respectively shown in a cross-sectional form in a perpendicular direction. As is clear from these figures, the automobile crash box 10 of the present embodiment (hereinafter simply referred to as the crash box 10) is formed of a cylindrical resin molded body having a honeycomb structure.

  The crash box 10 made of such a cylindrical resin molded body is formed by using a known resin molding technique such as injection molding. In addition, the material for forming the crash box 10 is not particularly limited as long as it is a resin material. Among various resin materials, there are materials that can ensure the impact absorption characteristics required for the crash box 10 and the like. Are appropriately selected and used. Examples of a resin material that can be suitably used as a material for forming the crash box 10 include composite resin materials such as glass fiber reinforced polypropylene, glass fiber reinforced polyamide, and carbon reinforced polypropylene.

  As shown in FIGS. 1 and 2, the crush box 10 includes seven cylindrical cells 12, 12, 12, 12, 12, 12, 12 having a hexagonal axial cross section. A honeycomb structure is formed by being integrated at adjacent positions.

  More specifically, here, a central cylindrical cell 12a consisting of one of the seven cylindrical cells 12a, 12b, 12c, 12d, 12e, 12f, and 12g is located at the center and around it. The six peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g are arranged adjacent to each other in a row in the circumferential direction so as to coincide with the axial direction of the central cylindrical cell 12a.

  That is, one central cylindrical cell 12a and six peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g are six sides of a hexagonal shape having a cross section perpendicular to the axis of the central cylindrical cell 12a. And the hexagonal side of the cross section perpendicular to the axis in each of the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g, and adjacent to the circumferential direction of the peripheral cylindrical cells 12b to 12g The objects share one side of the hexagonal shape perpendicular to the axis, and seven cylindrical cells 12a, 12b, 12c, 12d, 12e, 12f, and 12g are arranged.

  In other words, the central cylindrical cell 12a and the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, 12g are the six cylindrical wall portions 14, 14, 14, 14, 14, 14 of the central cylindrical cell 12a. And the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g, each of which is adjacent to each other in the circumferential direction among the peripheral cylindrical cells 12b to 12g. Seven cylindrical cells 12a, 12b, 12c, 12d, 12e, 12f, and 12g are arranged in a state where one cylindrical wall portion 14 is shared with each other.

  Thus, the crash box 10 includes a cylindrical peripheral wall 16, one central cylindrical cell 12 a inside the peripheral wall 16, and six peripheral cylindrical cells 12 b, 12 c arranged side by side around the central cylindrical cell 12 a. It is configured as a tubular honeycomb structure including partition walls 18 that partition and form 12d, 12e, 12f, and 12g. Here, among the cylindrical wall portions 14 of the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g, six cylindrical wall portions 14 and 14 extending radially from the six vertices of the central cylindrical cell 12a. , 14, 14, 14, 14 and the six cylindrical wall portions 14, 14, 14, 14, 14, 14 of the central cylindrical cell 12a constitute a partition wall 18. In addition, among the cylindrical wall portions 14 of the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g, a total of 18 cylindrical wall portions 14 arranged so as to surround the central cylindrical cell 12a from the outside. A peripheral wall 16 is constituted by the thing.

  And in this crash box 10, the area of the cross section in the direction perpendicular to the axis showing the hexagonal shape of each of the cylindrical cells 12a to 12g gradually increases from one end in the axial direction toward the other end. That is, here, among the cylindrical wall portions 14 respectively included in the six peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g, all the cylindrical wall portions 14 constituting the peripheral wall 16 are the six The distance between each of the peripheral cylindrical cells 12b, 12c, 12d, 12e, 12f, and 12g and the central axis P is gradually increased toward one side in the axial direction, that is, with respect to the central axis P. Are inclined with a predetermined inclination angle. Further, the six cylindrical wall portions 14, 14, 14, 14, 14, and 14 of the central cylindrical cell 12a also have a distance from the central axis P of the central cylindrical cell 12a toward the one side in the axial direction. It is arranged so as to increase gradually, that is, with a predetermined inclination angle with respect to the central axis P, respectively.

  In addition, the central axis of each cylindrical cell 12b-12g of the 18 things of the cylindrical wall part 14 which comprises the surrounding wall 16: The magnitude | size of the inclination angle with respect to P, and the central axis of each cylindrical wall part 14 of the central cylindrical cell 12a: The magnitude of the inclination angle with respect to P is not particularly limited, and can be changed as appropriate within a range in which the shock absorption characteristics required for the crash box 10 can be secured. In general, the inclination angle between each cylindrical wall portion 14 and the central axis P is set to a value within a range of about 3 to 20 degrees. This is because if the inclination angle is smaller than 3 degrees, it is difficult to smoothly mold the molded product when the crash box 10 is manufactured by die molding such as injection molding. This is because the moldability of 10 may be reduced, and when the inclination angle is larger than 20 degrees, the impact load may be reduced or the crash box 10 may be enlarged.

  Further, the thickness of each cylindrical wall portion 14 of the cylindrical cell 12 is not limited at all, and generally has a desired plastic deformation strength and is formed within a range in which the required shock absorption can be ensured. The thickness of the resin material used as the material is appropriately determined in consideration of the type of resin material and the like. This is because when the thickness of each cylindrical wall portion 14 is less than 2 mm, it is too thin, so that, for example, when the crash box 10 is manufactured by molding such as injection molding, melting in the molding cavity of the mold is performed. This is because the flowability of the resin material is lowered, and thereby the moldability of the crash box 10 may be lowered. If the thickness of each cylindrical wall portion 14 is thicker than 4 mm, the entire crash box 10 is formed. This is because there is a possibility that a problem arises that the weight of the crush box 10 is increased or the cooling time when the crush box 10 is molded by molding is increased, resulting in a longer molding cycle of the crush box 10.

  In the crash box 10, two through holes 20 are formed in each of the peripheral wall 16 and all the partition walls 18, i.e., all the cylindrical wall portions 14 of the cylindrical cells 12 a to 12 g. Yes. The through-hole 20 has a long, narrow rectangular slit shape that extends straight over the entire width in the width direction (direction perpendicular to the axial direction of the cylindrical cells 12a to 12g) with respect to each cylindrical wall portion 14. have. And the corner | angular part thru | or ridgeline formed between the two mutually adjacent cylindrical wall parts 14 and 14 is pierced only by the width | variety same as the width | variety of the through-hole 20 at the both ends of the extension direction of this through-hole 20 Cutout portions 22 and 22 are provided respectively. In the present embodiment, two through holes 20 provided in each of the cylindrical wall portions 14 are alternately arranged in the axial direction between the two adjacent cylindrical wall portions 14 and 14.

  Thus, in the crash box 10 of the present embodiment, each of the cylindrical cells 12a is formed by forming two through holes 20 in each of the cylindrical wall portions 14 of the cylindrical cells 12a to 12g. The plastic deformation strength of each cylindrical wall portion 14 in the axial direction of ˜12 g is reduced by a predetermined amount as compared with the case where such a through hole 20 is not provided. As a result, the plastic deformation strength in the axial direction of all the cylindrical wall portions 14 and thus the entire crash box 10 is tuned to a desired value.

  In addition, at both ends in the width direction of each through-hole 20, cutout portions 22, 22 formed by cutting a corner portion or a part of a ridge line formed between two cylindrical wall portions 14, 14 adjacent to each other, Since each is provided, the amount of increase or decrease in the size or width of each through-hole 20 compared to the case where the through-hole 20 is formed through only the intermediate portion excluding both ends in the width direction of each cylindrical wall portion 14. Thus, the plastic deformation strength in the axial direction of the entire crash box 10 can be tuned to a desired value more easily and reliably.

  In the crash box 10, outer flange portions 24 and 25 are integrally formed at both end portions in the axial direction. The two outer flange portions 24 and 25 are both formed from an annular flat plate that protrudes from the outer peripheral surface at both ends in the axial direction of the peripheral wall 16 at a predetermined height outward in the direction perpendicular to the axis and continuously extends in the circumferential direction. It has become. Each of the outer flange portions 24 and 25 has a plurality of bolt insertion holes 26 formed at predetermined intervals in the circumferential direction.

  Then, the crash box 10 of the present embodiment having such a structure, for example, as shown in FIG. 3, constitutes a bumper device 30 together with the bumper reinforcement 28, and is installed in the front part of the automobile. It has become so. In FIG. 3, an arrow F indicates a vehicle front side direction, an arrow R indicates a vehicle rear side direction, and an arrow W indicates a vehicle width direction.

  That is, as apparent from FIG. 3, the bumper reinforcement 28 constituting the bumper device 30 together with the crash box 10 is made of a long metal member having high rigidity, as in the prior art. And the crash box 10 is respectively provided with respect to the one end side site | part and the other end side site | part of the length direction in the surface (rear surface) located in the vehicle rear side in the installation state in the motor vehicle of this bumper reinforcement. Of the two end portions in the axial direction, the end surface of the end portion on the side where the cross section in the direction perpendicular to the axis is small is placed in contact with the end surface of the outer flange portion 24 provided at the end portion. Further, under such an arrangement state, each crash box 10 is attached to the bumper reinforcement 28 by the mounting bolts 32 inserted into the plurality of bolt insertion holes 26 provided in the outer flange portion 24 of each crash box 10. Bolts are fixed.

  Thus, one crush box 10 is provided at each of both ends of the rear surface of the bumper reinforcement 28 in the longitudinal direction, the direction perpendicular to the length of the bumper reinforcement 28, that is, the bumper reinforcement. It is arranged and fixed so that it extends toward the vehicle rear side under the installation state of 28 automobiles, and the cross-sectional area in the direction perpendicular to the axis gradually increases toward the vehicle rear side. Thereby, the bumper device 30 is configured as an integrated assembly of the bumper reinforcement 28 and the two crash boxes 10 and 10.

  As shown in FIG. 3, the bumper device 30 having such a structure has two bumper reinforcements 28 at the front part on the lower side of the automobile so as to extend in the vehicle width direction. The crash boxes 10, 10 are positioned so as to extend in the vehicle front-rear direction. Further, under such an arrangement, each of the two crush boxes 10 and 10 has an end face on an end portion on the side where the cross-sectional area in the direction perpendicular to the axis is large, and an outer flange portion 25 provided on the end portion. The end surfaces are arranged in contact with the front end surfaces of the pair of side members 34, 34 extending straight in the vehicle front-rear direction. Then, the two crash boxes 10, 10 are attached to the front end surfaces of the pair of side members 34, 34 by the mounting bolts 32 inserted through the plurality of bolt insertion holes 26 provided in the outer flange portion 25. Each bolt is fixed.

  Thus, both ends in the longitudinal direction of the bumper reinforcement 28 extending in the vehicle width direction, and a pair of side members 34 extending in the vehicle front-rear direction at a predetermined interval on the vehicle rear side of the bumper reinforcement 28, 34, one crush box 10 is inserted between each. The two crash boxes 10 and 10 extend in the vehicle front-rear direction between both ends of the bumper reinforcement 28 and the pair of side members 34, and have a cross-sectional area perpendicular to the axis. It is arranged so as to gradually increase toward the rear side of the vehicle, and is installed at the front part of the automobile.

  Therefore, an automobile in which the bumper device 30 including the two crash boxes 10 and 10 and the bumper reinforcement 28 is installed in the front part of the vehicle causes a collision accident or the like to the bumper reinforcement 28, for example. When an impact load is input, the impact load is transmitted to the two crash boxes 10 and 10 via the bumper reinforcement 28, and the two crash boxes 10 and 10 are moved in the axial direction. In FIG. 4, the plastic deformation is continuously performed in a bellows shape so that the impact energy can be absorbed.

  In the crash box 10 of the present embodiment, in particular, between the bumper reinforcement 28 and each side member 34, the vehicle extends in the vehicle front-rear direction, and the cross-sectional area perpendicular to the axis is the vehicle front side. It arrange | positions so that it may become large gradually as it goes to the back side from. Therefore, as indicated by the solid white arrows in FIG. 3, the input direction of the impact load transmitted to each crash box 10 via the bumper reinforcement 28 is the same as that of each crash box 10 that matches the vehicle longitudinal direction. Axial direction: When the direction is parallel to P, it goes without saying that each crush box 10 does not lie down side by side and stably plastically deforms in the axial direction. 3, the input direction of the impact load transmitted to each crash box 10 via the bumper reinforcement 28 is the axial direction of each crash box 10 as indicated by a two-dot chain line arrow or a dashed arrow in FIG. On the other hand, even in a direction inclined at a certain angle, each crash box 10 does not lie down as in the case where an impact load is input along the axial direction: P of each crash box 10. It is stable and plastically deforms in the axial direction.

  As is clear from the above description, the crash box 10 of the present embodiment is formed of a resin molded body, so that a sufficient weight reduction can be advantageously realized as compared with a conventional metal product. .

  In addition, although the crash box 10 is formed using a resin material having rigidity or strength lower than that of the metal material, the crash box 10 has a honeycomb structure, so that it has mechanical strength, particularly axial plasticity. The deformation strength can be sufficiently secured at a level comparable to that of a conventional metal product.

  Furthermore, in the crash box 10 of the present embodiment, the slit-like through holes 20 are provided in the cylindrical wall portions 14 of the plurality of cylindrical cells 12a to 12g constituting the honeycomb structure. The plastic deformation strength is adjusted. Therefore, in such a crash box 10, the elements related to the basic design of the crash box 10, such as the thickness of each cylindrical cell 12 a to 12 g and the type of forming material, are not changed in any complex manner, for example, The plastic deformation strength of the crash box 10 as a whole can be changed by simply changing the size of the through-hole 20 and the formation position of the through-hole 20 with respect to the cylindrical wall portion 14 of the cylindrical cells 12a to 12g. The shock absorption characteristics can be easily tuned.

  In the crash box 10, all of the cylindrical cells 12 a to 12 g extend between the bumper reinforcement 28 and the side members 34 in the vehicle front-rear direction and have a cross-sectional area perpendicular to the axis. However, it arrange | positions so that it may become large gradually as it goes to a back side from the vehicle front side. As a result, when the input direction of the impact load transmitted to each crash box 10 via the bumper reinforcement 28 is the direction parallel to the axial direction P of each crash box 10, the impact load is input. Even if the direction is an axial direction of each crash box 10: a direction inclined at a predetermined angle with respect to P, each crash box 10 does not lie down side by side and stably plastically deforms in the axial direction. It has become. Therefore, in such a crash box 10, when an impact load is input, the amount of plastic deformation in the axial direction is stably secured in a sufficient amount regardless of the input direction, and the impact energy is sufficiently high. And it can be stably absorbed.

  Therefore, according to the crash box 10 of the present embodiment as described above, it is possible to advantageously achieve a sufficient weight reduction while ensuring stable and effective shock absorption performance equivalent to that of a metal crash box. In addition, it is possible to easily tune the shock absorbing characteristics.

  Here, in order to compare the impact absorption characteristics (load-displacement characteristics) of a crash box having a structure according to the present invention with the impact absorption characteristics (load-displacement characteristics) of a crash box having a conventional structure, the present inventor The conducted tests will be described in detail.

  That is, first, as a crash box having a structure according to the present invention, a crash box having a structure as shown in FIGS. 1 and 2 was prepared and prepared. This was designated as Sample 1. In addition, the crush box of this sample 1 was produced by performing injection molding using glass fiber reinforced polypropylene. The crush box of the sample 1 has an axial length of 130 mm, a cylindrical wall thickness of the cylindrical cell: 2 mm, a cylindrical wall width at one axial end of the cylindrical cell: 60 mm, and a cylindrical shape. The width of the cylindrical wall portion at the other axial end of the cell: 70 mm, the central axis of the cylindrical cell: the inclination angle of the cylindrical wall portion with respect to P: 5 to 10 degrees, the length of the through hole: 5 mm, the width of the through hole: It was 30 mm.

  On the other hand, as a crash box having a conventional structure, a crash box made of iron and having a square cylinder shape in which the cross-sectional area perpendicular to the axis is constant in the axial direction and no through-hole is provided in the cylinder wall portion is manufactured. ,Got ready. This was designated as Sample 2. In addition, the crush box of the specimen 2 had an axial length: 130 mm, a cylinder wall thickness: 2 mm, and a cylinder wall width: 55 mm.

  And, in a state where the crush box of the specimen 1 is fixed on the base at the end portion on the side where the axial perpendicular direction cross-sectional area is large, with respect to the end portion on the side where the axial perpendicular direction cross-sectional area is small, A collision test in which an impactor weighing 1500 kg was collided at a speed of 15 km / h was performed according to a known method. Then, based on the measured value by the accelerometer provided in the impactor, the load-displacement characteristic of the crush box of the sample 1 was examined by a conventional method. The results are shown in FIG.

  Next, after fixing the crush box of the specimen 2 on the base at one end in the axial direction, the same collision test as that performed on the crush box of the specimen 1 is performed under the same conditions. It was. Thereafter, in the same manner as described above, the load-displacement characteristics of the crush box of the specimen 2 were examined. The results are also shown in FIG.

  As is clear from FIG. 4, in the crash box of the specimen 1 having the structure according to the present invention, in the initial stage of impact input, the load value increases rapidly with a small amount of displacement, and then the increase in the amount of displacement occurs. In other words, it is recognized that it has an ideal load-displacement characteristic (load-displacement curve) that draws a rectangular wave such that the load value changes at a substantially constant value. And it is also recognized that the load-displacement characteristic of such a specimen 1 is similar to the load-displacement characteristic of the crush box of the iron specimen 2 having a conventional structure. From these results, it can be clearly recognized that the crash box having the structure according to the present invention can ensure the excellent shock absorption characteristics equivalent to the iron crash box having the conventional structure.

  The specific configuration of the present invention has been described in detail above. However, this is merely an example, and the present invention is not limited by the above description.

  For example, in the embodiment, the crash box 10 is configured by integrating the seven cylindrical cells 12a to 12g with each other. However, the number of the cylindrical cells 12 constituting the crash box 10 is not limited to this, and is appropriately determined according to the axial plastic deformation strength, the shock absorption characteristics, etc. required for the crash box 10. Can be changed. Therefore, for example, as shown in FIGS. 5 and 6, four cylindrical cells 12 a, 12 b, 12 c, 12 d have several sides of a hexagon having a cross section perpendicular to the axis, that is, several cylindrical walls. The crash box 10 may be formed by sharing 14 and being integrated adjacent to each other. That is, the number of cylindrical cells 12 constituting the crash box 10 may be any number as long as it is plural. In addition, regarding the crash box 10 shown in FIGS. 5 and 6, the same reference numerals as those in FIGS. 1 and 2 are used for members and parts having the same structure as that of the embodiment shown in FIGS. 1 and 2. The detailed description is omitted by attaching.

  Further, the number of through holes 20 formed in the cylindrical wall portion 14 of the cylindrical cell 12 can be changed as appropriate. For example, as shown in FIGS. 5 and 6, each cylindrical wall portion 14 may be provided with only one through hole 20, or although not shown, each cylindrical wall portion 14 has a through hole. Three or more 20 may be provided.

  Further, the size and position of the through-hole 20 can be changed as appropriate according to, for example, required shock absorption characteristics and the number of formed holes on the cylindrical wall portion 14. For example, as shown in FIGS. 5 and 6, when only one through-hole 20 is formed in each cylindrical wall portion 14, as shown in FIGS. 1 and 2, The size of the through hole 20 can be increased as compared with the case where two through holes 20 are formed.

  Furthermore, the through holes 20 do not necessarily have to be provided in all the cylindrical wall portions 14 of the cylindrical cell 12, and only through those appropriately selected from the cylindrical wall portions 14 of the cylindrical cell 12. Even if the hole 20 is formed, there is no problem.

  Further, the crash box 10 may be disposed between the bumper reinforcement 28 and the side member 34 in a direction opposite to the direction shown in FIG. That is, the end of the crush box 10 on the side where the cross-sectional area on the axis perpendicular direction is large is positioned on the bumper reinforcement 28 side, while the end on the side where the cross-sectional area on the axis perpendicular direction is small is It is also possible to dispose it so that it extends in the vehicle longitudinal direction.

  Furthermore, as the attachment structure of the crash box 10 to the bumper reinforcement 28 or the side member 34, a known attachment structure other than the illustrated bolt fixing can be appropriately employed.

  In addition, the present invention provides a crash box and a bumper device arranged at the front of the automobile, a shock absorbing structure at the front of the automobile, a crash box and a bumper device arranged at the front of the automobile, Needless to say, the present invention can be advantageously applied to any of the shock absorbing structure at the rear, or the crash box or bumper device disposed in a vehicle other than the automobile, and the shock absorbing structure of a vehicle other than the automobile.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Crash box 12a Central cylindrical cell 12b-12g Peripheral cylindrical cell 14 Cylinder wall part 20 Through-hole 22 Notch part 28 Bumper reinforcement 30 Bumper apparatus 34 Side member

Claims (3)

A tubular body interposed between a bumper reinforcement extending in the vehicle width direction and a side member positioned at a distance in the vehicle longitudinal direction with respect to the bumper reinforcement. A crash box for a vehicle that absorbs impact energy by plastic deformation in the axial direction by an impact load input via the bumper reinforcement.
A honeycomb in which a cross section perpendicular to the axis has a hexagonal shape, and a plurality of cylindrical cells in which the area of the cross section perpendicular to the axis increases gradually toward one side in the axial direction are arranged adjacent to each other sharing at least one side A cylindrical resin molded body having a structure, and a through-hole for adjusting the strength against plastic deformation in the axial direction is formed on the cylindrical resin molded body. Vehicle crash box.   A bumper reinforcement that extends in the vehicle width direction, a pair of side members that are spaced from each other in the vehicle front-rear direction with respect to the bumper reinforcement, and both ends of the bumper reinforcement are respectively interposed. A vehicle bumper device comprising the vehicle crash box according to claim 1. 2. The vehicle according to claim 1, between a both ends of a bumper reinforcement extending in the vehicle width direction and a pair of side members positioned at a distance in the vehicle front-rear direction with respect to the bumper reinforcement. Each of the crash boxes is interposed, and the vehicle crash box is plastically deformed in the axial direction by an impact load input via the bumper reinforcement, and is configured to absorb impact energy. Vehicle shock absorption structure.

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