JP6445230B2 - Columnar member for improving maximum reaction force and absorbed energy amount against bending deformation due to impact - Google Patents

Description

  The present invention relates to a thin-walled columnar member used for an automobile body or the like.

  2. Description of the Related Art In order to reduce the weight and rigidity of a vehicle, an automobile forms a vehicle body by welding columnar members formed by plastically deforming thin plates so that the cross section has a so-called hat shape. In addition, in order to secure a living space in the passenger compartment in the event of a car collision, such a columnar member is required to increase the maximum reaction force and absorbed energy during bending deformation.

  For example, in Patent Document 1, a plurality of convex portions are provided on a pair of opposite side surfaces (wall surface portions), and the bending resistance characteristics are further improved by suppressing the outward deformation of the bending portion at the initial stage of bending deformation. A vehicle frame structure is disclosed.

JP 2011-16409 A

  However, in the vehicle frame structure described in Patent Document 1, the protrusions must be uniformly formed on the side wall, and it is very difficult to process the column member.

  An object of the present invention is to provide a columnar member having a hat-shaped cross section in which the maximum reaction force against bending deformation and the amount of absorbed energy are increased with a simple configuration. Yes.

In order to achieve the above object, according to the present invention, an upper wall extending along a predetermined main axis, side walls extending along both side edges of the upper wall, In a columnar member having a flange portion extending along the edge opposite to the wall, and having a substantially hat-shaped cross section perpendicular to the axis,
At least a pair of bead portions arranged symmetrically with respect to an axis defined by a line of intersection between the upper wall and a plane perpendicular to the main axis and the side wall surface is formed on the side wall. A featured columnar member is provided.

  According to the present invention, at least a pair of bead portions are provided on the side wall of the columnar member having a hat-shaped cross section, and the plane surface perpendicular to the main wall extending in the longitudinal direction of the columnar member and the columnar member and the side wall surface of the columnar member It is possible to increase the maximum reaction force and the absorbed energy against the bending deformation due to the external force in the axial direction by arranging the lines symmetrically with respect to the axis defined by the intersecting line with.

  Further, in the invention of Patent Document 1, the resistance force and the absorbed energy are increased only by suppressing the outward deformation of the member side wall in the cross section. However, in the present invention, by providing the bead portion, the deformation due to the collision is prevented. On the other hand, the outward deformation of the side wall of the side wall is suppressed, which not only increases the resistance and the amount of energy absorbed, but also keeps the bead portion unbroken and the portions located at the end of the remaining bead portion contact each other. By doing so, it becomes a fulcrum and resists deformation, increasing the resistance and the amount of absorbed energy.

FIG. 3 is an end view of a columnar member having a hat-shaped cross section according to a preferred embodiment of the present invention as viewed in the direction of arrow I-I in FIG. 2. It is a side view of the columnar member which has the hat-shaped cross section seen in the direction of arrow II-II of FIG. It is the schematic for demonstrating the approximate dimension of the columnar member used by simulation. It is the schematic for demonstrating the collision system which performed simulation. It is a figure which shows the simulation result of the columnar member of this invention which has a pair of bead part. It is a figure which shows the simulation result of the columnar member of the comparative example which is not provided with the bead part. It is a graph which shows the change of the reaction force with respect to the displacement of a striker about the columnar member of this invention and the columnar member of a comparative example. It is a graph which shows the change of the energy absorption amount with respect to the displacement of a striker about the columnar member of this invention and the columnar member of a comparative example. It is the bar graph which compared the change of the maximum reaction force about the several columnar member of this invention which changed the position of the front-end | tip point of a bead part. It is the bar graph which compared the change of the absorbed energy about the several columnar member of this invention which changed the position of the front-end | tip point of a bead part. It is the same graph as FIG. 7 which shows the change of the reaction force with respect to the displacement of a striker about the several columnar member of this invention which changed the position of the front-end | tip point of a bead part. It is the same graph as FIG. 8 which shows the change of the energy absorption amount with respect to the displacement of a striker about the several columnar member of this invention which changed the position of the front-end | tip point of a bead part.

A preferred embodiment of the present invention will be described below with reference to FIGS.
The columnar member 10 includes a flat plate-like upper wall 12 extending along a linear main axis Om perpendicular to the paper surface of FIG. 1 and side walls 14 extending along both side edges 12a and 12b of the upper wall 12. , 16 and flange portions 18, 20 extending along the opposite edge portions 14 a, 16 a of the side walls 14, 16, the longitudinal direction being the direction of the main axis Om of the columnar member 10 A cross section (cross section) cut along a plane perpendicular to the cross section is generally a hat shape.

  Bead portions 22 and 24 are provided on the side walls 14 and 16 of the columnar member 10. In the embodiment shown in FIGS. 1 and 2, the bead portions 22 and 24 are arranged symmetrically with respect to each other about the axis O that is the intersection of the upper wall 12 and the plane perpendicular to the main axis Om and the side wall. And a central axis Oc extending at an angle α with respect to the axis O so as to approach each other toward the upper wall 12, that is, to converge in a direction opposite to the external force F. It is extended along. In the embodiment shown in FIGS. 1 and 2, the bead portions 22 and 24 are formed so as to protrude inward from the side walls 14 and 16. However, the bead portions 22 and 24 may be formed so as to protrude outward from the side walls 14 and 16 as indicated by a two-dot chain line in FIG.

  A simulation (numerical analysis) of the deformation behavior of the columnar member 10 when an external force F is applied along the axis O to the upper wall 12 of the columnar member 10 having a hat-shaped cross section to which the present invention is applied is provided with a bead. Compared with no comparative examples. The comparative example has the same shape as the columnar member 10 of the present invention except that the bead is not provided.

  The schematic dimensions of the columnar member 10 used in the simulation are shown in FIG. In FIG. 3, the columnar member 10 has a length of 1000 mm, a width of the upper wall 12 of 60 mm, a maximum width (distance between outer edges of the flanges 18 and 20) of 120 mm, a width of each of the flange portions 18 and 20, 20 mm, and the side walls 14 and 16. The height is 60 mm. Beads 22 and 24 as shown in FIG. 2 are formed on the side walls 14 and 16. The beads 22 and 24 are inclined by 45 ° with respect to the axis O, have a width of 4 mm, a length of about 56.6 mm, and a height of about 2 mm.

  As shown in FIG. 4, the above-described columnar member 10 and the columnar member of the comparative example are bridged between a pair of cylinders 30 and 32 as fulcrums, and a columnar rigid body 40 having a mass of 200 kg is used as a striker, as indicated by an arrow. The deformation | transformation behavior of the columnar member 10 when making it collide with the upper wall 12 was simulated. The cylinders 30 and 32 as fulcrums are 50 mm in diameter and are fixed apart from each other with a distance (span) of 700 mm between the contacts Pt1 and Pt2 with the flange portions 18 and 20 of the columnar member 10. The simulation was performed under the condition of not moving at the striker collision. The collision speed of the striker to the upper wall 12 is 10 m / s.

  The simulation results are shown in FIGS. FIG. 5 shows the deformation behavior of the columnar member 10 according to the present invention, and FIG. 6 shows the deformation behavior of the columnar member of the comparative example. When the striker 40 collides, the columnar member is bent and deformed so that the upper wall 12 is recessed along the axis O in both the case of the present invention and the comparative example, and the side walls 14 and 16 bulge outward. As a result, the columnar member is deformed so as to be bent entirely around the axis O so as to be recessed in the direction of the arrow A. At that time, in the columnar member 10 according to the present invention, the bead portions 22 and 24 are deformed so as to be crushed in a direction perpendicular to the central axis Oc in a process in which the side wall 12 is deformed into a substantially V shape after the striker 40 collides. Then, in the side wall deformed into a substantially V shape, the points P located at the ends of the collapsed bead portions 22 and 24 on the side close to the central axis Oc are in contact with each other, and this serves as a fulcrum and the side wall is difficult to deform. At the same time, the movement (displacement) of the striker is prevented. In other words, in the present invention, (1) by providing the bead portions 22 and 24, the deformation of the side wall in the cross section outward is suppressed against the deformation due to the collision of the striker 40, thereby improving the resistance and absorbing. (2) In addition, the resistance P and the amount of energy absorbed by the points P located at the ends of the bead portions 22, 24 remaining without being crushed close to the center axis Oc contact each other. Will increase. On the other hand, in the comparative example, the deformation of the side wall proceeds, and the side wall is greatly bent as compared with the columnar member according to the present invention.

FIG. 7 shows a change in the reaction force with respect to the displacement of the striker 40 in the axis O direction.
In the columnar member according to the comparative example, the reaction force gradually decreases with respect to the displacement of the striker 40, and the side wall of the columnar member deformed into a substantially V shape at the final stage is located at the end of the bead portions 22 and 24 that remain without being crushed. In contrast to the columnar member according to the present invention, the reaction force increases early when the side wall abuts at the point P, and the displacement of the striker 40 is also a comparative example. Is smaller than

  FIG. 8 shows the energy absorption amount of the columnar member 10 with respect to the displacement of the striker 40 in the axis O direction. It will be understood from FIG. 8 that the columnar member 10 according to the present invention absorbs the same energy with a smaller displacement than the columnar member according to the comparative example.

Furthermore, the inclination angle α with respect to the axis O of the beads 22 and 24 provided on the side walls 14 and 16 was changed, and the changes in the maximum reaction force and the absorbed energy were compared. The comparison results are shown in Table 1.

  From Table 1, the effect of providing the beads 22 and 24 on the side walls 14 and 16 is recognized in a wide range of the inclination angle α, but the effect is high in the range of α = 20 ° to 75 °, particularly α = 45. It will be understood that the maximum reaction force and absorbed energy are maximized at °, and the highest effect is obtained.

Furthermore, the position of the tip point Pf of the beads 22 and 24 was changed, and the changes in the maximum reaction force and the absorbed energy were compared. The comparison results are shown in Table 2 and FIGS. In Table 2, Dx is the distance from the axis O in the direction parallel to the upper wall 12 to the tip point P, and Dy is the distance from the upper wall 12 to the tip point P in the direction perpendicular to the upper wall 12. It is.

  From Table 2 and FIGS. 9 and 10, both the maximum reaction force and the absorbed energy are more sensitive to changes in the distance Dx from the axis O than the distance Dy from the upper wall 12, and Dx = 5 mm and Dy = 5 mm. It will be understood that both cases are maximized in the case of.

  The bead portions 22 and 24 are described as being formed on the side walls 14 and 16 of the columnar member 10, but the present invention is not limited to this, and the bead portion 22 is provided on one of the side walls 14 and 16. , 24, the maximum reaction force and absorbed energy can be increased.

  The present invention can be applied to the body of an automobile.

DESCRIPTION OF SYMBOLS 10 Columnar member 12 Upper wall 14 Side wall 16 Side wall 18 Flange part 20 Flange part 22 Bead part 24 Bead part 30 Cylindrical member 32 Cylindrical member 40 Striker

Claims (4)

An upper wall extending along a predetermined main axis, side walls extending along both side edges of the upper wall, and extending along an edge of the side wall opposite to the upper wall In a columnar member having a flange portion, and a cross section perpendicular to the axis exhibits a substantially hat shape,
At least a pair of bead portions arranged symmetrically with respect to an axis defined by an intersection line between the upper wall and a plane perpendicular to the main axis and the side wall surface is formed on the side wall, and the bead portion Is extended along a central axis inclined at an angle of 20 to 75 ° in the surface of the side wall with respect to the axis, and a maximum reaction force and absorption against bending deformation due to collision Columnar member for improving energy.   The columnar member for improving the maximum reaction force and the amount of absorbed energy with respect to bending deformation due to a collision according to claim 1, wherein the bead portion protrudes inside the side wall. The columnar member for improving the maximum reaction force and the amount of absorbed energy with respect to bending deformation due to a collision according to claim 1, wherein the bead portion protrudes outside the side wall.   The columnar member for improving the maximum reaction force and the amount of absorbed energy with respect to bending deformation due to a collision according to any one of claims 1 to 3, wherein the side wall includes a plurality of pairs of bead portions.