JP6254448B2 - Bumper beam for vehicles - Google Patents

Description

  The present invention relates to a bumper beam for a vehicle that constitutes a bumper of an automobile or the like and absorbs energy at the time of a vehicle collision.

  Conventionally, a steel or light alloy bumper beam having a hollow structure and disposed in the vehicle width direction has been used as a strength member constituting a bumper provided at the front end or rear end of a vehicle body such as an automobile. Yes. In this type of bumper beam, it is known to provide a separator (reinforcing member) inside the hollow structure in order to increase the strength of the bumper beam.

  For example, in Patent Document 1, a reinforcing rib (separator) that is installed between a front surface of a bumper beam and a rear surface of the bumper beam is formed inside a rectangular tubular bumper reinforcing material (bumper beam) formed by roll-forming a high-tensile steel plate. It is disclosed. Thereby, the cross-sectional secondary moment of the bumper reinforcing material is increased, and the structural strength is improved.

  Further, Patent Document 2 discloses a bumper reinforcing member (bumper beam) having a hollow structure whose cross-sectional shape is made of an aluminum alloy extruded mold and has a mouth shape. This document describes that in order to reinforce the bumper reinforcing member, an intermediate rib (separator) is formed in the hollow structure, and the cross-sectional shape of the bumper reinforcing member is made to be a day shape, a square shape, an eye shape, or the like. Has been.

  Further, in Patent Document 3, a hollow energy absorbing member (separator) also made of aluminum alloy is inserted and fixed at a predetermined position inside a hollow structure of a bumper reinforcing material (bumper beam) made of an aluminum alloy extruded hollow member. Is disclosed. Thereby, the rigidity of the predetermined location of a bumper reinforcement can be improved and the impact energy absorption effect can be improved.

Japanese Utility Model Publication No. 11-170934 (page 3, FIG. 2) JP 2001-171446 A (page 4) JP 2000-52898 (page 4-5, FIG. 7)

  However, the above-described conventional technology has room for improvement from the viewpoint of further improving the collision safety performance while improving the productivity and reducing the weight.

  Specifically, as in the prior art described in Patent Document 1 or Patent Document 2, in the bumper beam having the same cross section in the extending direction, at the time of collision from the front direction (for example, at the time of full wrap barrier collision) Furthermore, the bumper beam tends to buckle near the center in the vehicle width direction where the bending moment is maximum. When the location is buckled, there is a problem that the collision energy cannot be absorbed efficiently and the collision stroke (deformation amount) increases.

  On the other hand, at the time of a collision from an oblique direction (for example, at the time of an offset collision), the bumper beam having the same cross-sectional shape in the extending direction described above collapses the cross-sectional shape of the bumper beam and efficiently absorbs the collision energy. However, there was a problem that the collision stroke increased.

  In addition, in a bumper beam having a sun-shaped cross section in which a separator is formed inside a hollow structure, the cross section of the bumper beam tends to be easily sheared in the vertical direction (vertical direction) at the time of collision.

  In response to these problems, by increasing the cross-section of the bumper beam, increasing the number of separators, or increasing the thickness of the material, the second-order moment of the bumper beam is increased, and the cross-sectional shape collapses. Can be prevented. However, these methods increase part weight and increase production costs.

  Further, by providing a small separator at a predetermined location as in the prior art described in Patent Document 3, it is possible to suppress the collapse of the cross-sectional shape of the bumper beam at that location. However, this method has a problem in that the number of parts of the bumper beam increases and assembly productivity decreases.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle bumper beam that is lightweight, excellent in productivity, and that exhibits excellent energy absorption performance against collisions from different directions. To do.

A bumper beam for a vehicle according to the present invention is a bumper beam having a hollow structure that is disposed in the vicinity of a front end portion or a rear end portion of a vehicle body and extends in a vehicle width direction, and includes an outer wall that forms a collision surface of the bumper beam, A separator extending between the inner wall facing the outer wall and extending in the vehicle width direction, wherein the separator is formed with a reinforcing portion displaced upward or downward in the vehicle width direction, and the bumper beam The both ends in the vehicle width direction are fixed to the vehicle body via a pair of left and right crash boxes that form a hollow structure, and the outer peripheral member that constitutes the crash box is configured in a polygonal shape in cross section. parts are at least one pair formed on both ends in the vehicle width direction, it is formed along at least two sides of the outer peripheral member constituting the crush box and said Rukoto.

  According to the vehicle bumper beam of the present invention, the separator extending between the outer wall and the inner wall of the bumper beam and extending in the vehicle width direction is formed with a reinforcing portion that is displaced upward or downward in the vehicle width direction. The Thereby, the intensity | strength and rigidity of a predetermined location can be improved, suppressing the mass increase of a bumper beam. As a result, it is possible to suppress the collapse of the cross-sectional shape of the bumper beam at the time of collision, efficiently absorb the collision energy, and shorten the collision stroke.

  Moreover, a pair of left and right reinforcing portions may be provided, and the reinforcing portions may be formed along the outer peripheral member constituting the crash box. As a result, the bumper beam can be prevented from collapsing during a collision, and the collision load can be efficiently transmitted to the crash box. As a result, the crushing load is increased and the impact energy absorption performance is improved.

  Further, the cross section of the crash box may be formed in a polygonal shape, and the reinforcing portion may be formed along at least two surfaces of the outer peripheral member constituting the crash box. Thereby, the load transmission to the crash box can be performed more effectively.

  The separator includes an inner wall extending from the outer wall to the inner wall, an outer flange portion bent from the inner wall and joined to the outer wall, and opposite to the outer flange portion from the inner wall. An inner surface side flange portion that is bent in the direction and joined to the inner surface wall. Accordingly, it is possible to increase the bonding strength between the separator and the outer surface wall or the inner surface wall to suppress the rotational deformation of the separator, and to prevent the cross-sectional shape of the bumper beam from collapsing.

  Further, the width of the bumper beam at the center in the vehicle width direction may be formed wider than the width of the bumper beam near both ends in the vehicle width direction. Thereby, the bending rigidity of the center part vicinity can be improved, avoiding the increase in mass, and the buckling of the said location can be prevented.

It is a perspective view which shows the bumper beam assembly which concerns on embodiment of this invention. It is an exploded perspective view same as the above. 4A is a front view (viewed in the direction of arrow A in FIG. 1), and FIG. 5B is a top view (viewed in the direction of arrow B in FIG. 3A). It is a horizontal cross section (C-C line sectional view of Drawing 3 (A)) same as the above. Same as above, (A) enlarged front view in the vicinity of the reinforcing portion (detailed view of D portion in FIG. 3A), (B) a schematic front view showing the positional relationship between the reinforcing portion and the crash box. It is a graph which shows the load-stroke characteristic at the time of (A) full wrap barrier collision, and (B) offset collision.

  Hereinafter, a vehicle bumper beam according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic structure of a bumper beam assembly 1 including a bumper beam 10 (vehicle bumper beam) according to an embodiment of the present invention. In FIG. 1, the upper left direction on the paper is the front of the vehicle, and the lower left direction on the paper is the left side of the vehicle.

  The bumper beam 10 is a strength member that constitutes a rear bumper of a vehicle such as an automobile, and absorbs energy at the time of a vehicle body collision. As shown in FIG. 1, the bumper beam 10 is a long member extending in the vehicle width direction, and is joined via a pair of left and right crash boxes 30 to a rear end portion of a floor panel 2 constituting a vehicle body such as an automobile. Is done.

  More specifically, the bumper beam 10 is joined to the crash box 30 and the crash box base 35, thereby forming the bumper beam assembly 1. The crash box base 35 of the bumper beam assembly 1 is mechanically fastened to the floor panel 2.

  Here, a pair of side frames 3 extending in the vehicle front-rear direction are provided below the left and right sides of the floor panel 2. The aforementioned crash box base 35 is connected to a position corresponding to the rear end of the side frame 3. Thereby, the side frame 3 can receive the load at the time of the collision transmitted from the crash box 30.

  FIG. 2 is an exploded perspective view of the bumper beam assembly 1 and shows a state seen from the same direction as FIG. As shown in FIG. 2, the bumper beam 10 includes an outer surface member 11, an inner surface member 12, and a separator 13.

  The outer surface member 11 is a member constituting an outer surface wall 14 that becomes a collision surface. The inner surface member 12 is a member constituting an inner surface wall 19 that faces the outer surface wall 14. The outer surface member 11 and the inner surface member 12 are joined to each other at their upper and lower portions. As a result, a hollow structure having a substantially rectangular cross section that forms the outer periphery of the bumper beam 10 and extending in the vehicle width direction is formed.

  The separator 13 is a reinforcing member provided inside the hollow structure formed by the outer surface member 11 and the inner surface member 12. Specifically, the separator 13 is a long member extending in the vehicle width direction, and is installed between the outer wall 14 and the inner wall 19. Reinforcing portions 25 are formed near both ends of the separator 13 in the longitudinal direction (vehicle width direction). Details will be described later.

  Further, as described above, the bumper beam assembly 1 includes the crash box 30 and the crash box base 35. The crash box 30 is a cylindrical member that extends in the front-rear direction of the vehicle, and is deformed at the time of collision to absorb collision energy. One end portion (end portion on the vehicle rear side) of the crash box is joined to the inner surface member 12 of the bumper beam 10, and the other end portion (end portion on the vehicle front side) is joined to the crash box base 35. The crash box base 35 is a member for joining the bumper beam assembly 1 to the floor panel 2 (see FIG. 1).

  Each member constituting the bumper beam assembly 1, that is, the outer surface member 11, the inner surface member 12, the separator 13, the crash box 30 and the crash box base 35 is formed, for example, by press forming a steel plate or a light alloy plate. . Further, the parts are joined to each other by welding, for example.

  FIG. 3 (A) is a front view of the bumper beam assembly 1 and shows a state of the bumper beam assembly 1 as viewed from the rear side of the vehicle (viewed in the direction of arrow A in FIG. 1). FIG. 3B is a top view of the bumper beam assembly 1 (viewed in the direction of arrow B in FIG. 3A).

  As shown in FIGS. 3A and 3B, the separator 13 has the same overall length as the outer surface member 11 and the inner surface member 12, and is provided substantially horizontally over the substantially entire length of the bumper beam 10. Thereby, the rigidity of the bumper beam 10 is increased over substantially the entire length.

  Further, as shown in FIG. 3A, a pair of reinforcing portions 25 bent so as to be displaced upward are formed in the vicinity of both end portions of the separator 13. The reinforcement part 25 is formed corresponding to the position where the crash box 30 is connected. Thereby, in the vicinity of the crash box 30, the cross section of the separator 13 can be made difficult to collapse, and the lateral cross section of the bumper beam 10 at the time of collision can be suppressed.

  As shown in FIG. 3B, the vehicle front-rear width W1 of the bumper beam 10 near the center in the vehicle width direction is wider than the vehicle front-rear width W2 of the bumper beam 10 near the ends in the vehicle width direction. Specifically, the outer surface wall 14 of the outer surface member 11 is curved in a substantially bow shape so that the vicinity of the center in the vehicle width direction bulges toward the rear of the vehicle when viewed from above. That is, the distance between the outer wall 14 and the inner wall 19 at the center in the vehicle width direction is longer than the distance in the vicinity of both ends in the vehicle width direction.

  Thereby, it is possible to increase the cross-sectional secondary moment in the vicinity of the center in the vehicle width direction of the bumper beam 10 at which the bending moment is maximized at the time of collision from the front direction (rear of the vehicle) (for example, at the time of full lap barrier collision). As a result, buckling of the vicinity of the center of the bumper beam 10 during a collision from the front direction can be suppressed, and collision energy can be efficiently absorbed to reduce the collision stroke.

  Here, as compared with the case of securing the same bending rigidity with the same cross-sectional shape as in the prior art, in the present embodiment, only the central portion having a large bending moment is configured widely, so that a predetermined strength is obtained. The weight of the bumper beam 10 can be reduced while ensuring.

  4 is a cross-sectional view taken along the line CC of FIG. 3 (A), and shows a cross section of the bumper beam assembly 1 at the center in the vehicle width direction. In FIG. 4, the left direction on the paper is the front of the vehicle. The cross-sectional structure of the bumper beam 10 is substantially the same as the cross-sectional structure described below over substantially the entire length.

  As shown in FIG. 4, the bumper beam 10 is disposed inside the bumper face 5 (the vehicle front side). The bumper face 5 is a member obtained by molding a synthetic resin into a predetermined shape, and covers the bumper beam 10 and constitutes a design surface of the rear bumper.

  The outer surface member 11 is bent in a convex shape toward the rear side of the vehicle, and has a substantially U-shaped cross section. Specifically, the outer surface member 11 is formed substantially perpendicularly to the rear side of the vehicle and forms an impact surface, and an upper surface that is continuously bent from the upper end of the outer surface wall 14 and extends forward of the vehicle. The wall 15 and the lower surface wall 16 continuously bent from the lower end of the outer surface wall 14 and extending forward of the vehicle.

  An inner surface member 12 constituting a substantially vertical inner surface wall 19 facing the outer surface wall 14 is provided on the vehicle front side of the outer surface member 11. The inner surface member 12 has a flange portion 20 that is continuously bent from the upper end of the inner surface wall 19 and extends toward the rear of the vehicle.

  The flange portion 20 is overlapped with the vicinity of the vehicle front side end portion of the upper surface wall 15 of the outer surface member 11, and the portion is joined by fillet welding or the like, for example. That is, the upper part of the outer surface member 11 and the inner surface member 12 is joined. The joining may be performed by spot welding by forming a flange portion having a predetermined shape.

  Further, a flange portion 17 that is bent continuously from the end portion and extends downward is formed at the end portion of the lower surface wall 16 of the outer surface member 11 on the vehicle front side. The flange portion 17 is overlapped with the lower portion of the inner surface member 12, and is joined to the inner surface member 12 by spot welding or the like, for example. That is, the outer surface member 11 and the inner surface member 12 are joined at their lower portions.

  Thus, in this embodiment, the upper and lower ends are joined to each other using two members, that is, the outer surface member 11 and the inner surface member 12, thereby extending in the vehicle width direction with a substantially rectangular cross section. A hollow structure is formed. Thereby, the bumper beam 10 can adopt a different cross-sectional shape depending on the position in the longitudinal direction, and can be easily assembled. For example, as described above, it is possible to form a wide width near the center.

  Moreover, you may form uneven | corrugated shape in the predetermined position in the outer surface wall 14 or the inner surface wall 19 as needed. As a result, the rigidity of the predetermined portion of the bumper beam 10 can be increased. For example, in the present embodiment, the outer wall 14 is formed with a recess 18 and the inner wall 19 is formed with a recess 21. In addition, the recessed part 18 and the recessed part 21 do not necessarily need to be formed over the full length of the bumper beam 10, and should just be formed in a predetermined location.

  In this way, by adopting a suitable cross-sectional shape at each position in the longitudinal direction so as to meet the strength conditions required for each position, the strength and rigidity of the bumper beam 10 can be improved while reducing the weight. be able to.

  The separator 13 is disposed in the hollow portion 37 of the hollow structure formed by the outer surface member 11 and the inner surface member 12, and is joined to the outer surface wall 14 and the inner surface wall 19. Specifically, the separator 13 connects the outer wall 14 and the inner wall 19 and is continuous from the inner wall 22 extending substantially horizontally in the vehicle width direction and the outer surface side (vehicle rear side) end of the inner wall 22. And an outer surface side flange portion 23 that is bent and extends downward, and an inner surface side flange portion 24 that continuously extends upward from the inner surface side (vehicle front side) end portion of the middle wall 22. That is, the separator 13 has a substantially Z shape in cross section.

  The outer surface side flange portion 23 is welded to the outer surface wall 14, and the inner surface side flange portion 24 is welded to the inner surface wall 19. Here, various methods can be employed as the welding method. For example, by performing spot welding on one side and plug welding on the other side, assembly and welding operations can be performed efficiently.

  In this way, the separator 13 has a substantially Z-shaped cross section, and the outer surface side flange portion 23 and the inner surface side flange portion 24 are bonded to the outer surface wall 14 and the inner surface wall 19, respectively. Can be increased. Thereby, rotational deformation of the separator 13 can be suppressed, and the cross-sectional shape of the bumper beam 10 can be prevented from collapsing at the time of collision.

  FIG. 5A is a detailed view of a portion D indicated by a chain line circle in FIG. 3A and is an enlarged front view of the bumper beam assembly 1 showing the vicinity of the reinforcing portion 25 of the separator 13. FIG. 5B is a schematic front view showing the positional relationship between the reinforcing portion 25 and the crash box 30.

  As shown in FIG. 5A, the reinforcing portion 25 is formed in the vicinity of the left end portion of the separator 13 in the vehicle width direction. Specifically, the reinforcing portion 25 is formed corresponding to a location where the crash box 30 is connected, and is formed so as to overlap the crash box 30 in a front view.

  In the reinforcing portion 25, the middle wall 22 extending in the vehicle width direction is bent and displaced upward. In other words, the separator 13 extending substantially horizontally is bent at the reinforcing portion 25 and displaced upward.

Specifically, the intermediate wall 22 extending substantially horizontally is bent upward at the bent portion 26 and continues to the wall 28 inclined obliquely upward toward the end portion. The wall 28 is bent at the bent portion 27 and connected to a wall 29 extending in the substantially horizontal direction from the wall 28 and the wall 29 displaced upward. The inner surface side flange portion 24 is formed continuously. That is, also about the reinforcement part 25, the separator 13 has comprised the cross-sectional substantially Z shape mentioned above.

  In addition, about the location where the hole for an assembly | attachment etc. are formed in the outer surface member 11 or the inner surface member 12, relief structure (notch etc.) is formed in the corresponding location of the outer surface side flange part 23 or the inner surface side flange part 24. Also good.

  As shown in FIG. 5B, the crush box 30 is formed in a polygonal cross section by joining an outer peripheral member 31 and an outer peripheral member 32 formed in a predetermined shape. The reinforcing portion 25 is formed along the outer peripheral members 31 and 32 of the crash box 30. More specifically, the reinforcing portion 25 is formed along at least two surfaces of the outer peripheral members 31 and 32 constituting the crash box 30.

  That is, the inclined wall 28 of the reinforcing portion 25 is formed substantially parallel to the surface 34 of the crash box 30, and the substantially horizontal wall 29 of the reinforcing portion 25 is formed substantially parallel to the surface 33 of the crash box 30. Further, the wall 28 intersects with the outer peripheral member 31 and the wall 29 intersects with the outer peripheral member 32 in the front view.

  Further, the flange portion 24 on the inner surface side of the separator 13 overlaps the surfaces 33 and 34 of the outer peripheral members 31 and 32 constituting the crash box 30 in a front view in the reinforcing portion 25. Thereby, the load at the time of a collision can be effectively transmitted to the crash box 30.

  As described above, by providing the reinforcing portion 25, it is possible to suppress the collapse of the cross-sectional shape of the bumper beam 10 at the time of collision. In particular, it is effective at the time of a collision from an oblique direction (for example, at the time of an offset collision), and shear deformation in which the outer wall 14 is relatively displaced upward and the inner wall 19 is relatively displaced downward can be suppressed.

  6A and 6B are graphs showing the load-stroke characteristics of the bumper beam assembly 1. FIG. 6A shows a full-wrap barrier collision, and FIG. 6B shows an offset collision. ing. In FIGS. 6A and 6B, the characteristic of the present embodiment is indicated by a solid line, and the characteristic of a conventional structure is indicated by a broken line as a comparison target. In the conventional structure shown here, a small separator having a vertically extending inner wall is disposed only in the vicinity of the crash box 30.

  As shown in FIG. 6A, in the full-wrap barrier collision, in the bumper beam assembly 1 according to the present embodiment, the crushing load is improved (dF) and the collision energy absorption efficiency is improved as compared with the conventional structure. The collision stroke is shortened (dS).

  As shown in FIG. 6B, even in the offset collision, according to the bumper beam assembly 1, the initial crushing load can be greatly improved (dF) compared with the conventional structure, and the collision energy absorption efficiency is improved. The collision stroke can be shortened (dS).

  As described above, the bumper beam 10 according to the present embodiment exhibits excellent collision energy absorption performance with respect to collisions from different directions.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above description, the reinforcing portion 25 has shown an example in which the separator 13 is displaced upward, but a configuration in which the separator 13 is displaced downward can be adopted instead. Even in such a case, by providing the reinforcing portion 25, the collapse of the cross-sectional shape of the bumper beam 10 can be suppressed, and the absorption efficiency of the collision energy can be improved.

  Moreover, in the above description, an example in which the two pressed members, that is, the outer member 11 and the inner member 12 are joined to form the hollow structure of the bumper beam 10 has been shown. However, instead of this, it is also possible to use a roll molding material or an extrusion molding material as the hollow structure and to provide the separator 13 having the reinforcing portion 25 inside thereof. Also in that case, the impact energy absorption effect can be enhanced by forming the reinforcing portion 25.

DESCRIPTION OF SYMBOLS 1 Bumper beam assembly 2 Floor panel 3 Side frame 5 Bumper face 10 Bumper beam 11 Outer surface member 12 Inner surface member 13 Separator 14 Outer wall 15 Upper surface wall 16 Lower surface wall 17 Flange portion 18 Recessed portion 19 Inner surface wall 20 Flange portion 21 Recessed portion 22 Middle wall 23 Outer surface Side flange portion 24 Inner surface side flange portion 25 Reinforcement portion 26 Bending portion 27 Bending portion 28 Wall 29 Wall 30 Crash box 31 Outer peripheral member 32 Outer peripheral member 33 surface 34 surface 35 Crash box base 37 Hollow portion

Claims (3)

A hollow bumper beam disposed in the vicinity of the front end or rear end of the vehicle body and extending in the vehicle width direction,
A separator extending between the outer wall constituting the collision surface of the bumper beam and the inner wall facing the outer wall and extending in the vehicle width direction;
The separator is formed with a reinforcing portion displaced upward or downward in the vehicle width direction ,
The bumper beam is fixed to the vehicle body via a pair of left and right crash boxes in the vicinity of both ends in the vehicle width direction, forming a hollow structure,
The outer peripheral member constituting the crash box is configured to have a polygonal cross section,
The reinforcing portion is at least one pair formed on both ends in the vehicle width direction, the vehicle bumper beam, characterized in Rukoto formed along at least two sides of the outer peripheral member constituting the crush box. The separator includes an inner wall extending from the outer wall to the inner wall, and an outer surface flange portion that is continuously bent from an end of the inner wall on the outer wall side and joined to the outer wall. And an inner surface side flange portion which is continuously bent from the inner wall side end portion of the inner wall and is bent in the opposite direction to the outer surface side flange portion and joined to the inner surface wall. The vehicle bumper beam according to claim 1 . Width of the bumper beam at the center of the vehicle width direction, the vehicle bumper beam according to claim 1 or claim 2, characterized in that it is wider than the width of the bumper beam at near both ends in the vehicle width direction.

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