JP2017124720A - Vehicle crash box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vehicle crash box by which impact absorption performance, which absorbs impact energy in the event of vehicle collision, can be maintained through hindrance of an increase in weight and with a simple structure.SOLUTION: A crash box 10 is a square tubular structure 11 with a closed cross-section, and is formed such that a plate thickness t1 of an upper wall part 16 and a lower wall part 18 is less than a plate thickness t2 of an external wall part 20 and an inner wall part 22. In addition, a recessed part 24 and a projecting part 26 are formed in the upper wall part 16 and the lower wall part 18 in a plate thickness direction, and a plurality of ridge lines P, Q, intersecting each other, are provided. Accordingly, in the crash box 10, the rigidity can be improved compared to the case where the ridge lines P, Q are not formed. That is, by hindering an increase in weight and increasing lateral flexure yield stress of the crash box 10 with a simple structure, external face deformation along a vehicle width direction of the crash box 10 can be hindered. Accordingly, impact energy can be effectively absorbed by the crash box 10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle crash box.

  Patent Document 1 below discloses a technique related to a crash box for a vehicle configured by a cylindrical resin body having a honeycomb structure. In this prior art, the crash box is made of a cylindrical resin body to reduce the weight, and by being made of a honeycomb structure, the plasticity in the axial direction is smaller than that of a resin body made of a simple cylindrical body. Strength against deformation is improved. That is, here, although the crush box is a cylindrical resin body, it is possible to ensure the shock absorbing performance of absorbing the impact energy at the time of the vehicle collision by configuring the honeycomb structure.

JP 2014-004973 A

  However, in this prior art, since the crash box has a complicated structure in order to maintain the shock absorbing performance, there is room for further improvement.

  In consideration of the above-described facts, an object of the present invention is to obtain a vehicle crash box that can suppress an increase in weight and can maintain a shock absorbing performance that absorbs shock energy at the time of a vehicle collision with a simple structure.

  The crash box for a vehicle according to claim 1 is a square tube-like closed cross-section structure formed of fiber reinforced resin, a pair of first wall portions disposed on both outer sides in the vehicle width direction, A second wall portion disposed at an upper portion and a lower portion in the direction and formed thinner than a plate thickness of the pair of first wall portions, and at least one of the upper portion and the lower portion of the second wall portion. A concave portion and a convex portion are formed in the plate thickness direction of the second wall portion, and a plurality of ridge lines connecting the concave portion and the convex portion are provided and intersect each other.

  The crash box for a vehicle according to claim 1 is a closed cross-sectional structure of a rectangular tube shape made of fiber reinforced resin. The vehicular crash box has a pair of first wall portions on both outer sides in the vehicle width direction, and a second wall portion on the upper and lower portions in the vehicle vertical direction, and the plate thickness of the second wall portion is Each of the pair of first wall portions is formed thinner than the plate thickness. Further, at least one of the upper part and the lower part of the second wall part is formed with a concave part and a convex part in the thickness direction of the second wall part, and a plurality of ridge lines connecting the concave part and the convex part are provided and intersect each other. Yes.

  For example, the crash box for a vehicle is arranged at each end in the vehicle width direction of the bumper reinforcement extending along the vehicle width direction at the front portion of the vehicle, and toward the rear side in the vehicle front-rear direction of the bumper reinforcement. Each is fixed.

  For this reason, during a frontal collision of the vehicle, an impact load is transmitted to the vehicle crash box via the bumper reinforcement. At this time, if a lateral bending stress acts on the vehicle crash box, the vehicle crash box may be deformed out of plane and fall down along the vehicle width direction (so-called cross-sectional collapse). In such a case, the vehicular crash box does not undergo axial compression deformation that deforms along the axial direction, and the impact energy absorption by the vehicular crash box does not function well.

  For this reason, first, in the crash box for a vehicle, the plate thickness of the first wall portion provided on both outer sides in the vehicle width direction is increased (thickened). Thereby, higher rigidity can be obtained in the first wall portion, and the lateral bending resistance of the vehicle crash box can be increased.

  Here, if the first wall portion is thickened, the weight of the vehicle crash box increases correspondingly, and the load generated by the vehicle crash box increases in the event of a vehicle collision. For this reason, in the vehicle crash box, it is necessary to reduce the plate thickness (thinner) in the second wall portion as much as the first wall portion is thickened. For this reason, in this invention, it forms so that the plate | board thickness of a 2nd wall part may become thinner than the plate | board thickness of a 1st wall part.

  Next, when the said 2nd wall part is made thin, the possibility that predetermined | prescribed rigidity cannot be ensured in the crash box for vehicles arises. For this reason, in this invention, a recessed part and a convex part are formed in the plate | board thickness direction of the said 2nd wall part in at least one among the upper part and the lower part of a 2nd wall part, and the ridgeline which connects the said recessed part and a convex part is provided. Cross each other (so-called diamond cut shape).

  Thus, by providing a plurality of ridge lines intersecting each other in the vehicle crash box, the rigidity of the vehicle crash box can be increased as compared with the case where the ridge lines are not formed. That is, by changing the shape of the second wall portion, the rigidity of the second wall portion can be improved without changing the plate thickness. Here, since the second wall portion is simply made into a diamond-cut shape, the vehicular crash box itself can have a simple structure.

  Therefore, in the present invention, it is possible to suppress lateral deformation along the vehicle width direction of the vehicle crash box by increasing the lateral bending resistance of the vehicle crash box in a state where an increase in weight is suppressed. Thereby, impact energy can be effectively absorbed by the crash box without hindering the axial compression deformation of the crash box for the vehicle.

  The crash box for a vehicle according to claim 2 is a cylindrical closed cross-section structure formed of fiber reinforced resin, and includes a cylindrical portion composed of a pair of upper and lower semicircular portions in the vehicle vertical direction, and the pair of A flange portion that extends outward in the radial direction of the semicircular portion along the vehicle width direction and is joined to each other, and the flange portion is formed with a concave portion and a convex portion in the plate thickness direction of the flange portion. A plurality of ridge lines connecting the concave portions and the convex portions are provided and intersect each other.

  The crash box for a vehicle according to claim 2 is a cylindrical closed section structure formed of fiber reinforced resin. The vehicular crash box has a cylindrical portion composed of a pair of upper and lower semicircular portions in the vertical direction of the vehicle. Flange portions project along the vehicle width direction to the outside in the radial direction of the pair of semicircular portions, and are joined to each other.

  Here, compared with a polygonal member, a cylindrical part is a shape which has rigidity higher than the said polygonal member, and is hard to carry out an out-of-plane deformation. For this reason, in the said crash box for vehicles, when a cylindrical part and a flange part are compared, the rigidity of a flange part becomes lower than a cylindrical part. Accordingly, in the present invention, in the flange portion, a concave portion and a convex portion are formed in the plate thickness direction of the flange portion, and a plurality of ridge lines connecting the concave portion and the convex portion are provided and intersect with each other.

  As described above, the present invention has an excellent effect of suppressing the increase in weight and maintaining a shock absorbing performance that absorbs shock energy at the time of a vehicle collision with a simple structure.

It is the perspective view seen from the vehicle diagonal left front side which shows the bumper reinforcement which fixed the crash box for vehicles which concerns on 1st Embodiment, and the said crash box for vehicles. It is the expansion perspective view to which the crash box for vehicles fixed to the left side of the bumper reinforcement shown in FIG. 1 was expanded. It is sectional drawing which shows the state cut | disconnected along the 3-3 line of FIG. (A) is a top view for demonstrating an oblique collision, (B) is a top view for demonstrating a center pole collision. It is an expansion perspective view corresponding to Drawing 2 showing the crash box for vehicles concerning a 2nd embodiment.

  Hereinafter, embodiments of a crash box for a vehicle according to the present invention will be described with reference to the drawings. It should be noted that arrow FR, arrow UP, arrow W, and arrow OUT, which are appropriately shown in the drawings, respectively indicate the front direction (traveling direction), the upward direction, the vehicle width direction, and the vehicle width direction outside of the vehicle. In the following description, when simply using the front / rear, up / down, and left / right directions, unless otherwise noted, the front / rear direction of the vehicle, the up / down direction of the vehicle, and the left / right direction (vehicle width direction) of the vehicle. Show left and right.

<First Embodiment>
(Vehicle crash box configuration)

  First, the configuration of the vehicle crash box according to the present embodiment will be described. FIG. 1 shows a vehicle crash box (hereinafter simply referred to as “crash box”) 10 and a bumper reinforcement 12 to which the crash box 10 is fixed.

  The bumper reinforcement 12 is, for example, a rectangular tubular closed cross-sectional structure 13 that extends along the vehicle width direction at the front portion of the vehicle, and the cross-sectional shape cut along the vehicle front-rear direction is rectangular. It is made. The crash box 10 is fixed to the rear wall portion 14 of the bumper reinforcement 12.

  As shown in FIG. 2, the crash box 10 is a rectangular cylindrical closed cross-sectional structure 11 having a longitudinal direction in the vehicle front-rear direction, and the cross-sectional shape cut along the vehicle width direction is a rectangular shape. ing. The crash box 10 includes an upper wall portion (second wall portion) 16 that constitutes an upper portion, a lower wall portion (second wall portion) 18 that faces the upper wall portion 16 and constitutes a lower portion, and an outer side in the vehicle width direction. An outer wall portion (first wall portion) 20 that connects the upper wall portion 16 and the lower wall portion 18, and the outer wall portion 20 that faces the outer wall portion 20 and is located on the inner side in the vehicle width direction. And an inner wall portion (first wall portion) 22 that connects the two.

  Here, the crash box 10 is made of fiber reinforced resin, and the plate thickness t1 of the upper wall portion 16 and the lower wall portion 18 of the crash box 10 is thinner than the plate thickness t2 of the outer wall portion 20 and the inner wall portion 22. It is formed to become (thin wall). Further, the upper wall portion 16 and the lower wall portion 18 are formed with a concave portion 24 and a convex portion 26 in the plate thickness direction, and a plurality of ridge lines P connecting the concave portion 24 and the convex portion 26 are provided and intersect each other.

  More specifically, the upper wall portion 16 and the lower wall portion 18 have a so-called diamond cut shape, and the diamond cut portion 15 includes a plurality of square pyramids 28 in which truss 28A (triangular skeleton structure) is three-dimensionally combined. Is configured. The plurality of quadrangular pyramids 28 are arranged along the vehicle front-rear direction and the vehicle width direction, and the center of each quadrangular pyramid 28 is a convex portion 26 and the outer periphery is a concave portion 24 in plan view.

  Each quadrangular pyramid 28 is provided with four ridge lines P connecting the convex portions 26 and the concave portions 24, and the ridge lines P intersect each other. In addition, the outer periphery of each quadrangular pyramid 28 has four ridge lines Q, and a truss 28A is formed by the ridge lines Q and the two ridge lines P. Here, as shown in FIG. 3, the position of the convex portion 26 of the upper wall portion 16 and the position of the concave portion 24 of the lower wall portion 18 are arranged so as to overlap vertically. Further, in the case of the lower wall portion 18, a portion that protrudes with the lower wall portion 18 facing upward is a convex portion 26, and a concave portion is a concave portion 24.

(Operation and effect of vehicle crash box)
Next, functions and effects of the vehicle crash box according to the present embodiment will be described.

  For example, as a form of frontal collision of a vehicle, there are so-called oblique collision and center pole collision. As shown in FIG. 4 (A), the oblique collision refers to a form in which the barrier Br1 collides relative to the end side in the vehicle width direction of the bumper reinforcement 12 from the oblique front side. Further, as shown in FIG. 4 (B), the center pole collision refers to a form in which a pole-like barrier Br2 such as a standing tree or a utility pole collides relatively with the central portion of the bumper reinforcement 12 in the vehicle width direction. .

  As shown in FIGS. 4A and 4B, when barriers Br1 and Br2 collide with bumper reinforcement 12, impact load (F1, F2) is applied to crash box 10 via bumper reinforcement 12. Each will be transmitted.

  However, since these impact loads (F1, F2) are not input on the axis of the crash box 10, lateral bending stress acts on the crash box 10. Thereby, for example, although not illustrated, the crash box 10 may be deformed out of plane and fall down along the vehicle width direction. In such a case, the crash box 10 is not subjected to axial compression deformation that deforms along the axial direction, and the impact energy absorption by the crash box 10 does not function well.

  Therefore, in the present embodiment, first, as shown in FIGS. 2 and 3, the crash box 10 is formed as a square cylindrical closed cross-section structure 11, and the plate thickness t <b> 2 of the outer wall portion 20 and the inner wall portion 22 is increased. (Thick). Thereby, higher rigidity can be obtained in the outer wall portion 20 and the inner wall portion 22, and the lateral bending resistance of the crash box 10 can be increased. Here, “the plate thickness t2 is increased in the outer wall portion 20 and the inner wall portion 22” means that the plate thickness t2 is t2> t, where t is the original plate thickness.

  Here, if the outer wall portion 20 and the inner wall portion 22 are thickened, the weight of the crash box 10 is increased correspondingly, and the load generated by the crash box 10 is increased during a vehicle collision. For this reason, in the crash box 10, it is necessary to reduce (thinner) the plate thickness t1 of the upper wall portion 16 and the lower wall portion 18 by the amount that the outer wall portion 20 and the inner wall portion 22 are thickened. Here, “reducing the thickness t1 of the upper wall portion 16 and the lower wall portion 18” means that the thickness t1 is t1 <t, where t is the original thickness. As a result, in the present embodiment, the plate thickness t1 of the upper wall portion 16 and the lower wall portion 18 is formed to be thinner than the plate thickness t2 of the outer wall portion 20 and the inner wall portion 22 (t1 <t2). .

  Next, when the upper wall portion 16 and the lower wall portion 18 are thinned, there is a possibility that a predetermined rigidity cannot be secured in the crash box 10. For this reason, in this embodiment, the upper wall part 16 and the lower wall part 18 are made into a diamond-cut shape, and the recessed part 24 and the convex part 26 are formed in the plate | board thickness direction of the upper wall part 16 and the lower wall part 18. A plurality of ridgelines P connecting the concave portions 24 and the convex portions 26 are provided and intersect each other.

  Thus, by providing a plurality of ridge lines P that intersect with each other in the crash box 10, the rigidity of the crash box 10 can be increased as compared with the case where the ridge lines P are not formed.

  That is, by changing the shapes of the upper wall portion 16 and the lower wall portion 18, the rigidity of the upper wall portion 16 and the lower wall portion 18 can be improved without changing the plate thickness. In other words, by changing the shapes of the upper wall portion 16 and the lower wall portion 18, the rigidity of the upper wall portion 16 and the lower wall portion 18 is improved, and thus the plate thickness of the upper wall portion 16 and the lower wall portion 18 is reduced. be able to.

  By reducing the plate thickness of the crash box 10, it is possible to reduce the load generated by the crash box 10 at the time of a vehicle collision. For example, damage to the barrier Br1 shown in FIG. 4A can be reduced. Further, by reducing the plate thickness of the crash box 10, the weight of the vehicle can be reduced, and as a result, the fuel consumption of the vehicle can be improved. And in this embodiment, since the upper wall part 16 and the lower wall part 18 are only made into a diamond-cut shape, the crash box 10 itself can be made into a simple structure.

  Therefore, in the present embodiment, it is possible to suppress the increase in weight and increase the lateral bending proof strength of the crash box 10 with a simple structure, thereby suppressing the out-of-plane deformation of the crash box 10 along the vehicle width direction. Thereby, impact energy can be effectively absorbed by the crash box 10 without inhibiting the axial compression deformation of the crash box 10. That is, according to this embodiment, the safety performance at the time of a vehicle collision improves.

(Other embodiments)
In the present embodiment, as shown in FIG. 3, the position of the convex portion 26 of the upper wall portion 16 and the position of the concave portion 24 of the lower wall portion 18 are arranged so as to overlap vertically. However, since it is sufficient that the axial compression deformation of the crash box 10 is not hindered, the present invention is not limited to this. For example, although not illustrated, the position of the convex portion 26 of the upper wall portion 16 and the position of the convex portion 26 of the lower wall portion 18 may be arranged so as to overlap each other.

  In the present embodiment, as shown in FIG. 2, the upper wall portion 16 and the lower wall portion 18 are formed with a plurality of quadrangular pyramids 28 in which a truss 28A is three-dimensionally combined as a diamond-cut shape. The quadrangular pyramids 28 are arranged along the vehicle front-rear direction and the vehicle width direction. However, it is only necessary that the recesses 24 and the projections 26 are formed in the plate thickness direction of the upper wall portion 16 and the lower wall portion 18 and a plurality of ridge lines P connecting the recesses 24 and the projections 26 are provided. is not.

  For example, although not illustrated, the adjacent quadrangular pyramids 28 may be arranged to be staggered in the vehicle front-rear direction and the vehicle width direction. In addition, the diamond-cut shape does not necessarily need to be composed of a plurality of quadrangular pyramids 28, and may be composed of a plurality of hexagonal pyramids or a plurality of pyramid frustums. Furthermore, the diamond cut shape may be composed of a single square pyramid 28 or the like.

  Moreover, in this embodiment, although the upper wall part 16 and the lower wall part 18 of the crash box 10 are made into a diamond-cut shape, either one of the upper wall part 16 and the lower wall part 18 is a diamond-cut shape. It may be said. Furthermore, not only the upper wall part 16 and the lower wall part 18, but the outer wall part 20 and the inner wall part 22 may be formed in a diamond-cut shape. In this case, the plate | board thickness of the outer wall part 20 and the inner wall part 22 can be made thinner than t2.

Second Embodiment
Next, a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the site | part equivalent to 1st Embodiment, and detailed description (a common effect | action is also included) is abbreviate | omitted suitably.

  In the first embodiment, as shown in FIG. 2, the crush box 10 is a closed cross-section structure 11 having a rectangular tube shape, but the shape of the crush box is not limited to this. For example, as shown in FIG. 5, the crash box 30 may be a cylindrical closed section structure 31.

  Here, the crash box 30 is composed of a pair of upper and lower parts, and the upper part 32 and the lower part 34 constitute cylindrical parts 36 and 38. The upper portion 32 of the crash box 30 includes a pair of semicircular portions 36A and 38A disposed along the vehicle width direction. Between the semicircular portion 36A and the semicircular portion 38A, a connecting piece ( (Flange portion) 40A is provided, and flange portions 42A and 44A project from the ends of the semicircular portions 36A and 38A along the radial direction on the opposite side of the connection piece 40A.

  On the other hand, the lower portion 34 of the crash box 30 includes a pair of semicircular portions 36B and 38B arranged along the vehicle width direction, and between the semicircular portion 36B and the semicircular portion 38B, Similar to the upper portion 32, a connecting piece (flange portion) 40B that connects the semicircular portion 36B and the semicircular portion 38B is provided. Further, on the opposite side of the connection piece 40B, flange portions 42B and 44B project from the end portions of the semicircular portions 36B and 38B along the radial direction, respectively.

  Then, the flange portion 42B, the connecting piece 40B and the flange portion 44B on the lower portion 34 side of the crash box 30 and the flange portion 42A, the connecting piece 40A and the flange portion 44A on the upper portion 32 side of the crash box 30 are joined by adhesion or welding, respectively. As a result, the cylindrical portions 36 and 38 are formed.

  Here, although not shown, the cylindrical portions 36 and 38 have a shape that is higher in rigidity than the polygonal member and difficult to be deformed out of plane as compared to the polygonal member. That is, in the cylindrical closed cross-section structure 31, it is not necessary to change the plate thickness in the circumferential direction of the cylindrical portions 36 and 38 with respect to the lateral bending stress.

  In the crash box 30, the cylindrical portions 36 and 38, the flange portions 42A and 42B, the connection pieces 40A and 40B, and the flange portions 44A and 44B are formed with the same plate thickness. For this reason, when both are compared, the rigidity of flange part 42A, 42B, connection piece 40A, 40B, and flange part 44A, 44B becomes lower than cylindrical part 36,38.

  Accordingly, in the present embodiment, the diamond cut portion 15 is provided in which the flange portions 42A and 42B, the connection pieces 40A and 40B, and the flange portions 44A and 44B have a diamond cut shape. Thereby, predetermined rigidity is ensured in flange part 42A, 42B, connection piece 40A, 40B, and flange part 44A, 44B.

  In the present embodiment, the crash box 30 includes two cylindrical portions 36 and 38, but the number of cylindrical portions may be one.

  In the above embodiment, the crash box fixed to the so-called front bumper reinforcement arranged at the front part of the vehicle has been described. However, even if it is applied to a crash box fixed to the so-called rear bumper reinforcement arranged at the rear part of the vehicle. Good.

  Although one embodiment of the present invention has been described here, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be combined as appropriate, or the present invention may be used. Needless to say, the present invention can be implemented in various forms without departing from the gist of the invention.

10 Crash box (crash box for vehicles)
11 closed cross-section structure 16 upper wall (second wall)
18 Lower wall (second wall)
20 outer wall (first wall)
22 Inner wall (first wall)
24 Concave part 26 Convex part 30 Crash box 31 Closed cross-section structure 36 Cylindrical part 36A Semicircular part 36B Semicircular part 38 Cylindrical part 38A Semicircular part 38B Semicircular part 40A Connection piece (flange part)
40B Connection piece (flange)
42A Flange part 42B Flange part 44A Flange part 44B Flange part P Edge line t2 Plate thickness (plate thickness of the first wall)

Claims (2)

It is a closed cross-section structure of a square tube formed of fiber reinforced resin,
A pair of first wall portions disposed on both outer sides in the vehicle width direction;
A second wall portion disposed at an upper portion and a lower portion of the vehicle in the vertical direction, each formed thinner than a plate thickness of the pair of first wall portions;
With
At least one of the upper part and the lower part of the second wall part is formed with a concave part and a convex part in the thickness direction of the second wall part, and a plurality of ridge lines connecting the concave part and the convex part are provided and intersect each other. Crash box for vehicles. It is a cylindrical closed section structure formed of fiber reinforced resin,
A cylindrical portion composed of a pair of upper and lower semicircular portions in the vertical direction of the vehicle;
A flange portion projecting along the vehicle width direction to the outside in the radial direction of the pair of semicircular portions, and joined to each other;
With
A crash box for a vehicle, wherein a concave portion and a convex portion are formed in the flange portion in a plate thickness direction of the flange portion, and a plurality of ridge lines connecting the concave portion and the convex portion are provided and intersect each other.

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