JP2012001023A - Vehicle body member of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently restrain impact force, by always causing axial crush deformation, regardless of the input action direction of the impact force caused when a vehicle meets with a collision accident.SOLUTION: When constituted in a cross-sectional hat shape out of a long side body 4 of forming a cross section perpendicular to the axis in a substantially U shape by a pair of vertical walls 2 and a horizontal wall 3 for connecting mutual one end side side end parts 2a of both vertical walls 2 and a flange part 5 respectively formed so as to extend in its longitudinal direction in the respective other end side side end parts 2b in the pair of vertical walls 2 for constituting the body 4, a gradually changing part 10 is formed by gradually and continuously changing a cross-sectional shape perpendicular to the axis of the body 4 in the longitudinal axis direction over the collision rear end side B from the collision front end side A in the longitudinal axis direction of the body 4, and the cross-sectional area perpendicular to the axis of the collision rear end side B is set larger than the cross-sectional area perpendicular to the axis on the collision front end side A.

Description

  The present invention relates to a vehicle body member member of an automobile that constitutes a vehicle body skeleton component such as a side member, a cross member, a pillar, or a side sill of an automobile body.

  This type of vehicle body member generally has a long main body having a substantially U-shaped cross section perpendicular to the axis and a pair of flange portions extending in the longitudinal direction at both ends of the main body. The cross section has a substantially hat shape.

  Such a vehicle body member member, for example, a side member installed so as to extend in the front-rear direction of the vehicle body, exists on the rear side from the front side of the collision existing on the front side of the vehicle when the vehicle encounters an accident and collides. It is configured to cause axial crushing deformation in the axial direction toward the rear end side of the collision, which is a fixed end, to be crushed and to mitigate the impact caused by the collision accident.

  In order to smoothly perform the axial crushing deformation at the time of the collision of the automobile, one of the conventional vehicle body member members is, for example, a long body that is substantially U-shaped. A concave or convex crushing bead is formed on a wall surface of a pair of vertical walls or a wall of a horizontal wall connecting the two vertical walls to each other so as to intersect the axis, and the crushing bead is used as a trigger. It was intended to cause axial crushing deformation (see Patent Document 1).

  In addition, among other conventional vehicle body member members, the other vehicle body member member is configured with a polygon having a pentagonal cross section or more in the middle part of the main body, in which the cross section perpendicular to the axis is substantially rectangular, and when subjected to a collision load In addition, the cross-sectional deformation part at the boundary between the cross-sectional square and the polygon more than the pentagonal cross-section is used as a crushing deformation trigger part, causing the axial crushing deformation to crush and reduce the impact caused by the collision accident. (See Patent Document 2).

  Further, among other conventional vehicle body member members, another vehicle body member member has an octagonal closed cross section at the front half of the vehicle and a quadrangular closed cross section at the rear half, and an intermediate portion between the front half and the rear half. The closed cross-sectional shape is configured by providing a cross-sectional change part that gradually changes from an octagon to a quadrangle from the first half side to the second half side, and the crushing strength of the cross-section change part is set higher than that of the first half and the second half part. is there.

JP 55-136660 A (see FIGS. 3 and 4) Japanese Patent Laid-Open No. 6-20576 (see FIGS. 1 to 3) Japanese Patent Laid-Open No. 8-26133 (see FIG. 6, FIG. 7, etc.)

  However, this type of vehicle body member, for example, in the case of a side member member, as described above, when encountering an automobile collision, the rear end of the collision existing on the rear side from the front side of the collision existing on the front side of the automobile. It functions to crush by causing axial crushing deformation along the axis (from the front side to the rear side of the car) toward the side, and to mitigate the impact caused by a collision accident. Is not necessarily applied along the longitudinal direction of the vehicle body, that is, along the axial direction of the vehicle body member member. In an oblique collision of an automobile, the impact on the vehicle body member member intersects the axial direction of the side member member. Input action in the direction (the vehicle body left-right direction including the oblique direction with respect to the side member member), and attempts to bend the side member member In such a case, the crushing bead in Patent Document 1, the cross-sectional deformation part in Patent Document 2 or the cross-sectional change part in Patent Document 3 triggers the bending deformation, and It is conceivable that the intermediate portion is bent and deformed, and the axial tensile force cannot be sufficiently achieved and the desired axial crushing performance cannot be exhibited.

  In view of the problems in the conventional technology as described above, the present invention always causes axial crushing deformation regardless of the input action direction of the impact force generated when the automobile encounters a collision accident or the like, thereby improving the axial crushing performance. An object of the present invention is to provide a vehicle body member member for an automobile in which the impact force is effectively suppressed.

  An automobile body member according to the present invention includes a pair of vertical walls and a long main body having a substantially perpendicular U-shaped cross section formed by a horizontal wall connecting end portions on one end side of both vertical walls. And a vehicle body member of an automobile configured to have a hat-shaped cross section by flange portions respectively formed so as to extend in the longitudinal direction at end portions on the other end side of the pair of vertical walls constituting the main body Forming a gradual change portion that gradually and gradually changes the cross-sectional shape of the main body perpendicular to the longitudinal axis direction from the front end side to the rear end side in the longitudinal axis direction of the main body. The cross-sectional area perpendicular to the axis on the front end side of the collision is set to be larger than the cross-sectional area perpendicular to the axis on the rear end side of the collision.

  In the present invention having such a configuration, the cross-sectional shape perpendicular to the axis of the main body has a gradually changing portion gradually and gradually changing in the longitudinal axis direction from the collision front end side to the collision rear end side in the longitudinal axis direction. By setting the axis perpendicular cross-sectional area on the rear end side larger than that on the front end side, there is no deformation part that triggers bending deformation as in the prior art, and the collision occurs from the front end side of the collision. The axial crushing deformation load gradually increases as it goes to the rear end side, preventing the middle part from being bent and improving the maximum load, regardless of the input direction of the impact force caused by a car crash etc. The axial crushing deformation is always caused to improve the axial crushing performance, and the impact force can be efficiently suppressed.

  Further, the vehicle body member member of the automobile according to the present invention includes, as an embodiment, a ridge line formed by connecting each one end side end of each of the vertical walls and the horizontal wall, and each of the other vertical walls. The gradual change portion is formed by curving at least one of ridge lines defined by connecting the end portion on the end side and the flange portion with a constant curvature in an arc shape with respect to the longitudinal axis direction of the main body. Is configured.

  In the present invention having such a configuration, the ridgeline formed by connecting the one end side end portions and the horizontal wall in both vertical walls or the other end side end portion and the flange portion in both vertical walls are defined. Since the ridge line that has a constant curvature has an ablation part formed in an arc shape, it does not have a deformation part that triggers bending deformation as in the prior art, such as an automobile collision accident, etc. Regardless of the input direction of the impact force generated by, the axial crush deformation is always improved to improve the shaft crush performance and prevent the middle part from being bent, effectively suppressing the impact force and increasing the maximum load. Can be improved.

  The vehicle body member according to the present invention includes, as an embodiment, a ridge line formed by connecting the one end side end of the both vertical walls and the horizontal wall, and the other end of the two vertical walls. By forming at least one of the ridge lines defined by connecting the side end portion and the flange portion with a certain angle, the main body is inclined with respect to the longitudinal axis direction, and the gradual change is performed. Part.

  In the present invention having such a configuration, a ridgeline formed by connecting the end portions on one end side of the vertical walls and the horizontal wall or the end portion on the other end side of the vertical walls and the flange portion are connected. Since the formed ridge line is inclined at a certain angle and is formed in an inclined shape with respect to the longitudinal axis direction of the main body and has other variable parts, the deformation part that triggers the bending deformation as in the prior art is provided. Regardless of the input direction of the impact force caused by a car collision accident, etc., it always causes axial crushing deformation to improve axial crushing performance and prevent the middle part from being bent. The impact force can be efficiently suppressed and the maximum load can be improved.

  Moreover, the vehicle body member member of the automobile according to the present invention is configured by forming stepped step beads extending over the entire length in the longitudinal direction on the wall surfaces of the two vertical walls as an embodiment.

  The present invention having such a configuration can increase the ridgeline on the wall surfaces of both vertical walls by the step beads extending over the entire length in the longitudinal direction of the wall surfaces of both vertical walls, thereby increasing the surface rigidity according to the Kalman effective theory. As a result, it is possible to reinforce the load resistance for preventing the intermediate portion from being bent to sufficiently exhibit the axial crushing performance and to improve the maximum load.

Moreover, the vehicle body member member of the automobile according to the present invention is configured by forming a plurality of the step beads on the wall surface of the vertical wall as an embodiment.
In the present invention having such a configuration, a plurality of step beads formed on both vertical walls, ridge lines are further added to both vertical walls, and the surface rigidity according to Kalman's effective theory can be increased, This can further improve the axial crushing performance.

  According to the present invention described above, the cross-sectional shape perpendicular to the axis of the main body has a changeover section that gradually and gradually changes in the longitudinal axis direction from the collision front end side to the collision rear end side in the longitudinal axis direction. Since the cross-sectional area on the axis perpendicular to the front end of the collision is set larger than the cross-sectional area on the axis on the rear end of the collision, there is no deformation part that triggers bending deformation as in the prior art, and from the front end of the collision. The axial crushing deformation load gradually increases as it goes to the rear end side of the collision, preventing the middle part from being bent, improving the maximum load, and depending on the input direction of the impact force caused by a car crash or the like. Therefore, the axial crushing deformation is always caused to improve the axial crushing performance, and the impact force can be efficiently suppressed.

1 is a schematic perspective view of a side member that is a vehicle body member according to a first embodiment that employs the present invention. It is the schematic bottom view which removed the step bead in FIG. It is the figure which drawn the example of an experimental model which this inventor experimented until it reached this invention. FIG. 4 is a diagram depicting changes in the maximum load efficiency when each experimental model shown in FIG. 3 is axially collapsed. It is a schematic perspective view of the side member which is a vehicle body member which concerns on Example 2 which employ | adopted this invention. It is the schematic bottom view which removed the step bead in FIG. It is the general | schematic bottom view which removed the step bead of the side member which is a vehicle body member which concerns on Example 3 which employ | adopted this invention. It is the schematic bottom view which removed the step bead of the side member which is a body member member concerning Example 4 which adopted the present invention. It is a schematic perspective view of the side member which is a vehicle body member which concerns on Example 5 which employ | adopted this invention.

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

  First, a side member (generally referred to as a rear side member or the like) disposed on the rear side of a vehicle body as a vehicle body member member according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The side member 1 includes a pair of vertical walls 2 and 2 and a lateral wall 3 that connects the end portions 2a and 2a of the vertical walls 2 and 2 to each other, and the cross section perpendicular to the axis is substantially U-shaped. The elongated main body 4 and the flange portion 5 formed so as to extend in the longitudinal direction of the other end side end portions 2b and 2b of the pair of vertical walls 2 and 2 constituting the main body 4, 5 and a hat shape in cross section.

  The side member 1 is attached to a vehicle body 6 indicated by a two-dot chain line by spot welding or the like with the flange portions 5 and 5 as attachment portions, and constitutes a strength member having a closed cross section.

  Then, the front end of the collision in the axial direction of the ridge line 2c (the front side of the drawing) on one side of the ridge lines 2c and 2b defined by connecting the other end side end 2b and the flange portion 5 in both the vertical walls 2 and 2. From the side (e.g., the front side of the automobile) A to the rear end side (e.g., the rear side of the automobile) B of the collision, the gradual continuous gradual by curving with a constant curvature in the longitudinal axis direction (left-right direction in FIG. 1). The gradual change portion 10 is formed so that the area perpendicular to the longitudinal axis on the rear end side of the collision is set larger than the sectional area perpendicular to the longitudinal axis on the front end side A of the collision.

  Furthermore, step-like step beads 7 and 7 projecting outward are formed on the wall surfaces 2e and 2e of both the vertical walls 2 and 2, respectively, so as to extend over the entire length in the longitudinal direction. Of both step beads 7, 7, the ridge line 7a of one step bead 7 (the front side of the drawing) is also curved and formed with a certain curvature along the ridge line 2c.

  Therefore, the axially perpendicular cross-sectional shape of the main body 4 is changed from the collision front end side A to the rear collision end side B in the longitudinal axis direction by the gradually changing portion 10 formed in an arc shape gradually and continuously in the longitudinal axis direction X of the main body 4. The cross-sectional area perpendicular to the axis A on the front end side A of the collision is set larger than the cross-sectional area on the right side A on the rear end side B, so that there is no deformation part that triggers bending deformation as in the prior art. Moreover, the axial crushing deformation load is gradually increased from the collision front end side A to the collision rear end side B to improve the axial crushing performance, prevent the middle portion from being bent, and improve the maximum load. Regardless of the input direction of the impact force caused by a collision accident or the like, it is possible to constantly cause the shaft crushing deformation to improve the shaft crush performance and to efficiently suppress the impact force.

  Further, the step beads 7, 7 extending over the entire length in the longitudinal direction of the wall surfaces 2 e, 2 e of both the vertical walls 2, 2, the step beads 7, 7 are placed on the wall surfaces 2 e, 2 e of both the vertical walls 2, 2. The ridge line 7a is formed by connecting the wall surfaces 2e and 2b to each other. In addition to the ridge line 2c, the ridge line formed in the main body 4 is increased, and the surface rigidity according to the Kalman effective theory is increased. As a result, it is possible to reinforce the load resistance for preventing the intermediate portion from being bent, to sufficiently exhibit the axial crushing performance and to improve the maximum load.

  Next, with reference to FIG. 3 and FIG. 4, an experimental model that has been experimented until reaching the configuration of the first embodiment according to the present invention and the experimental result of the maximum load according to each experimental model will be described.

  FIG. 3 shows an experimental model for a configuration in which the side members in the experimental model E, which is a prior art, are parallel to the ridgeline formed by connecting the vertical wall and the flange portion over the entire length. D is the one where the rear end side of the collision is formed with an arc-like gradually changing portion in the range of about 1/3 in the longitudinal direction, and the experimental model C forms the ridge line on the front side of the collision from the center in the longitudinal direction in parallel and the front end of the collision The side is formed in an arc-shaped gradual change part, the experimental model B is formed in an arc-like gradual change part in the range of 2/3 in the longitudinal direction, and the experimental model A corresponds to Example 1 according to the present invention. Thus, a ridge line formed by connecting one vertical wall 2 and the flange portion 5 is formed in an arc shape over the entire length in the longitudinal direction, and formed in a gradually changing portion.

  The inventor used the above experimental models A to E to reproduce the similar state of an actual automobile collision accident, and as a result, the results shown in FIG. 4 were obtained.

  In FIG. 4, the horizontal axis represents the length of the parallel portion formed in the axial direction of the vehicle body member member, and the vertical axis represents the maximum load for the axial crushing force in each experimental model.

  According to FIG. 4, first, for an experimental model in which the step beads 7 are not formed, among the experimental results, an experiment according to the present invention in which the curved exfoliation portion 10 is formed over the entire length in the longitudinal axis direction of the vehicle body member member. Model A was able to obtain a result of a significant improvement in the maximum load with respect to experimental models B to D having a shorter change-over part.

  Further, even in the experimental model in which the step bead is formed, the experimental model A according to the present invention in which the curved exfoliation part 10 is formed over the entire length in the longitudinal axis direction of the vehicle body member member is an experiment in which the excision part is shorter than that. As a result, the maximum load can be significantly improved with respect to the models B to D. In addition, the maximum load is further improved as compared with the case where the step beads 7 are not formed.

  However, when the maximum loads in the experimental model A according to the present invention and the experimental model E in the prior art are compared, almost the same values are shown.

  However, since the experimental model E in the prior art is a vehicle body member that is parallel to the entire length in the longitudinal axis direction, it is certain that the impact force due to a car crash or the like is applied in parallel to the longitudinal axis direction. However, if the impact force acts in a direction in which the vehicle body member is bent with respect to the longitudinal axis direction, the load will be reduced to a low load. There is an experimental result that it will bend and reduce the axial crush performance.

  Further, in the experimental model E, since the maximum load with respect to the impact force parallel to the longitudinal axis direction is large, in order to exert a predetermined axial crushing performance, the cause of axial crushing deformation on the surface portion of the vertical wall or the horizontal wall is unavoidable. It is necessary to form a collapsed bead or the like, and it has been found in the experiment of the inventors that the maximum load in the longitudinal axis direction is significantly reduced as a result of forming such a collapsed bead.

  In this respect, the vehicle body member according to the present invention is configured such that the axially perpendicular cross-sectional shape of the main body 4 is gradually changed side by side in the longitudinal axis direction of the main body due to the presence of the change changing portion 10, Since the cross-sectional area at the rear end B of the collision is set to be larger than the cross-sectional area at the right-hand axis, a large maximum load can be obtained while improving the axial pressure performance without forming a conventional crushing bead or the like. In addition, the impact force input directionality is not limited by an automobile collision accident or the like, and a constant impact force relaxation performance can be realized.

  Next, Embodiment 2 according to the present invention will be described with reference to FIGS.

  The side member 1 according to the second embodiment shown in FIG. 5 and FIG. 6 is defined by connecting the other end side end portion 2b and the flange portion 5 of the vertical wall 2 on one side of the vertical walls 2 and 2. The ridgeline 2c is gradually and gradually changed by inclining at a certain angle, and the longitudinal axis perpendicular area on the rear end side of the collision is larger than the longitudinal cross section of the longitudinal axis on the front end side A of the collision. The gradual change portion 10 is formed so as to be set.

  Further, on each of the wall surfaces 2e and 2e of the vertical walls 2 and 2, stepped step beads 7 projecting outward are formed so as to extend over the entire length in the longitudinal direction. A ridge line 7a defined by connecting the step beads 7, 7 and the wall surfaces 2e, 2e is inclined with a certain angle along the ridge line 2c.

  By configuring as described above, the ridge line 2c defined by connecting the other end side end portion 2b and the flange portion 5 of the vertical wall 2 on one side of the vertical walls 2 and 2 has a certain angle. The cross-sectional shape perpendicular to the axis of the main body 4 is formed so as to gradually and gradually change in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction X. Since the deformed portion 10 exists, the axis perpendicular cross-sectional area on the collision rear end side B is set larger than the axis perpendicular cross-sectional area on the collision front end side A. The axial crushing deformation load gradually increases from the collision front end side A to the collision rear end side B to improve the shaft crushing performance and prevent the intermediate part from being bent. Impacts caused by automobile collision accidents by improving the load Regardless of the input direction, causing the constantly axis crush deformation, it is possible to efficiently suppress the impact force.

  Further, the step beads 7, 7 extending over the entire length in the longitudinal direction of the wall surfaces 2 e, 2 e of both the vertical walls 2, 2, the step beads 7, 7 are placed on the wall surfaces 2 e, 2 e of both the vertical walls 2, 2 e. The ridgelines 7a and 7a that are defined by connecting the wall surfaces 2e and 2e are formed. In addition to the ridgeline 2c, the ridgelines formed in the main body 4 are increased, and according to Kalman's effective theory. The surface rigidity can be increased, and as a result, the axial crush performance can be improved to prevent the intermediate portion from being bent, and the axial crush performance can be sufficiently exhibited and the maximum load can be improved.

  The side member 1 according to Example 3 shown in FIG. 7 has ridgelines 2c and 2c that define both the vertical walls 2 and 2 by connecting the other end side end portions 2b and 2b and the flange portions 5 and 5 respectively. It is formed in an arc shape with a constant curvature, and the axially perpendicular cross-sectional shape of the main body 4 is gradually and gradually changed in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction. The cross-sectional area perpendicular to the axis B at the rear end B of the collision is set larger than the cross-sectional area perpendicular to the axis A at the front end A.

  Therefore, the ridgelines 2c and 2c that define the two vertical walls 2 and 2 by connecting the other end side end and the flanges 5 and 5 are formed in an arc shape with a certain curvature, so that The right-angle cross-sectional shape gradually and continuously changes in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction. Since the cross-sectional area perpendicular to the axis on the rear end side B is set to be large, there is no deformation part that triggers bending deformation as in the prior art, and the axial crushing proceeds from the collision front end side A to the collision rear end side B. Regardless of the input direction of the impact force caused by a car crash, etc., the deformation load gradually increases and the shaft crushing performance is improved to prevent the middle part from being bent and the maximum load is improved. Efficient impact with constant axial crushing deformation It is possible to suppress.

  Further, due to the step beads 7 and 7 extending over the entire length in the longitudinal direction of the wall surfaces 2e and 2b of both the vertical walls 2 and 2, the step beads 7 and 7 and the wall surface 2e, As a result, ridge lines 7a and 7a are formed which are connected to each other 2b, and the ridge lines formed on the main body 4 in addition to the ridge line 2c are increased, thereby increasing the surface rigidity according to Kalman's effective theory. As a result, it is possible to improve the axial crush performance and prevent the intermediate portion from being bent, to sufficiently exhibit the axial crush performance and improve the maximum load.

  Next, the side member 1 according to the fourth embodiment shown in FIG. 8 includes a ridgeline 2c that defines both the vertical walls 2 and 2 by connecting the other end side end portions 2b and 2b and the flange portions 5 and 5; 2c is formed in an inclined shape with a certain angle, and the cross-sectional shape perpendicular to the axis of the main body 4 is gradually and gradually changed in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction. Thus, by forming the gradual change portion 10, the cross-sectional area perpendicular to the axis B on the rear end B of the collision is set larger than the cross-sectional area perpendicular to the axis A on the front end A.

  Accordingly, the ridgelines 2c and 2c defined by connecting the other end side end portion and the flange portions 5 and 5 together with the vertical walls 2 and 2 are formed in an inclined shape with a certain angle, and the shaft of the main body 4 The right-angle cross-sectional shape of the collision front end side A on the axis A on the collision front end side A is formed by the gradual change portion 10 formed by gradually and gradually changing in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction. Since the cross-sectional area perpendicular to the rear end B of the area with respect to the area is set large, there is no deformation part that triggers bending deformation as in the prior art, and the rear end B The axial crushing deformation load gradually increases as it goes to improve the axial crushing performance to prevent the middle part from being bent, improve the maximum load, and input the impact force caused by automobile collision accident etc. Regardless of the direction, it always causes axial crushing deformation. , It is possible to effectively suppress the impact force.

  The side member 1 according to the fifth embodiment shown in FIG. 9 collides from the front end A of the collision in the axial direction of the ridgelines 2f and 2f that define the gradual change portion 10 by connecting the vertical walls 2 and 2 and the horizontal wall 3 to each other. With respect to the rear end side B, it is gradually and gradually changed by curving with a constant curvature in the longitudinal axis direction (left and right direction in FIG. 9), and with respect to the longitudinal axis perpendicular to the longitudinal direction of the collision front end side A The gradual change portion 10 is formed such that the area perpendicular to the longitudinal axis on the rear end side of the collision is set to be large.

  Furthermore, step-like step beads 7 and 7 projecting outward are formed on the wall surfaces 2e and 2e of both the vertical walls 2 and 2, respectively, so as to extend over the entire length in the longitudinal direction. A ridge line 7a defined by connecting the step beads 7 and 7 and the wall surfaces 2e and 2e, respectively, is curved with a certain curvature along the ridge line 2c.

  By configuring as described above, the ridge line 2c defined by connecting the other end side end of the vertical walls 2 and 2 and the horizontal wall 3 is formed in an arc shape with a certain curvature, and the main body 4 The gradual change portion 10 that gradually changes gradually in the longitudinal axis direction from the collision front end side A to the collision rear end side B in the longitudinal axis direction is present. By setting the cross-sectional area larger than the cross-sectional area on the axis B perpendicular to the rear end of the collision, there is no deformation part that triggers bending deformation as in the prior art, and the rear end side of the collision from the front end side A of the collision As B goes, the axial crushing deformation load gradually increases to improve the axial crushing performance to prevent the middle part from being bent, to improve the maximum load, and to improve the impact force caused by a car crash, etc. Regardless of the input direction, constant axial deformation Hips, it can be efficiently suppressed impact force.

  Further, due to the step beads 7 and 7 extending over the entire length in the longitudinal direction of the wall surfaces 2e and 2b of both the vertical walls 2 and 2, the step beads 7 and 7 and the wall surface 2e, 2e and 7e are formed to form the ridgelines 7a and 7a, and the ridgelines formed in the main body 4 in addition to the ridgeline 2c are increased, thereby increasing the surface rigidity according to the Kalman effective theory. As a result, it is possible to improve the axial crush performance and prevent the intermediate portion from being bent, to sufficiently exhibit the axial crush performance and improve the maximum load.

  As described above, according to the present invention, the axially perpendicular cross-sectional shape of the main body has a change-over section that gradually and gradually changes in the longitudinal axis direction from the collision front end side to the collision rear end side in the longitudinal axis direction. In addition, since the cross-sectional area at the rear end of the collision is set larger than the cross-sectional area at the front end of the collision, the front end of the collision does not have a deformation part that triggers bending deformation as in the prior art. The axial crushing deformation load gradually increases from the end to the rear end of the collision, preventing the middle part from being bent, improving the maximum load, and in the input direction of impact force caused by a car crash, etc. Regardless, it always causes axial crushing deformation, improves axial crushing performance and efficiently suppresses impact force, and body frame parts such as side members, cross members, pillars or side sills of automobile bodies It is suitable to a vehicle body member member of an automobile constituting.

1 Side member (body member)
2 Vertical wall 2c Ridge line 2e Wall surface 3 Horizontal wall 4 Body 5 Flange part 6 Car body 7 Step bead 7a Ridge line 10 Gradual change part

Claims (5)

A pair of vertical walls and a long main body having a cross section perpendicular to the axis formed by a horizontal wall connecting the end portions on one end side of both vertical walls, and the pair of vertical walls constituting the main body. A vehicle body member member having a cross-sectional hat shape formed by a flange portion formed so as to extend in the longitudinal direction at each other end side end portion of the wall, the vehicle body member member being perpendicular to the axis of the main body An axially perpendicular cross-sectional area on the front side of the collision is formed by forming a change-over section that gradually and gradually changes the cross-sectional shape in the longitudinal axis direction from the collision front end side to the rear collision end side in the longitudinal axis direction of the main body. A vehicle body member for an automobile, wherein the cross-sectional area perpendicular to the rear end of the collision is set to be large. A ridge line formed by connecting the one end side ends of the vertical walls and the horizontal wall, and a ridge line formed by connecting the other end side ends of the vertical walls and the flange part. 2. The vehicle body member according to claim 1, wherein at least one of the gradually changing portions is curved in a circular arc shape with respect to the longitudinal axis direction of the main body by curving at least one. At least one of a ridge line connecting each one end side end portion of the both vertical walls and the horizontal wall and a ridge line connecting the other end side end portion of the both vertical walls and the flange portion has a certain angle. The vehicle body member according to claim 1, wherein the gradually changing portion is formed to be inclined with respect to the longitudinal axis direction of the main body by being inclined. 4. The vehicle body member according to claim 1, wherein stepped beads extending over the entire length in the longitudinal direction are formed on the wall surfaces of the two vertical walls. 5. . 5. The vehicle body member according to claim 4, wherein a plurality of the step beads are formed on a wall surface of the vertical wall.

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