JP5341607B2 - Bumper beam structure for vehicles - Google Patents

Description

  The present invention relates to a structure of a vehicle bumper beam connected to a vehicle body via a crash box.

A bumper beam in a vehicle contributes to energy absorption by being crushed by itself in response to an offset collision. However, there is a case in which a crash box is provided because the absorbed energy may not be sufficient only by crushed the bumper beam. That is, the end of the bumper beam is connected to a side member that is a skeleton member of the vehicle body via a crash box. Since the crushing load at the time of collision is bumper beam <crash box, the bumper beam is crushed in the first stage of the collision, and then the crash box is crushed to continue energy absorption, thereby protecting the side member from the collision load. In order to increase the amount of energy absorbed by the crash box, it is necessary to lengthen the crash box in the longitudinal direction of the car body. There is a structure that is connected to the opposite surface of the bumper beam through a portion (Patent Documents 1 and 2).
JP 2006-176093 A JP-A-2005-271734

  In Patent Document 1, the bumper beam connecting portion with the crash box has an opening structure on the vehicle body side, so that the crash box can be extended to the bumper beam facing surface through this opening portion. Therefore, the amount of collision energy absorbed can be increased accordingly. However, the bumper beam is usually a pressed product of a metal plate material, and the rigidity is lowered by adopting the rear opening structure, and the function of protecting the components such as a radiator is insufficient when the bumper beam collides with the beam body. In Patent Document 2, the bumper beam is composed of a beam body having an open rear surface and a second member integrated with the beam body by welding so as to close the rear surface opening of the beam body. While the bending rigidity is maintained while increasing the amount of energy absorption at the time of collision by increasing the length in the front-rear direction, the bumper beam has a split structure consisting of the beam body and wing body over its entire length (full body width). In addition, it has an integrated structure by welding, and there is a problem that the cost becomes high both in terms of material and processing.

  The present invention has been made in view of the above problems, and realizes an increase in the amount of energy absorption with respect to a collision and a high rigidity with respect to a collision with a beam body without increasing the cost in terms of material cost and processing cost. For the purpose.

  According to the present invention, there is provided a vehicle bumper beam that extends in the vehicle body width direction between the side members on both sides of the vehicle body and is connected to the end portions of the side members via the respective crash boxes. It consists of a beam body whose both ends in the width direction stay in front of each crash box, and a wing body formed separately from the beam body and extending outward in the vehicle body width direction from each end of the beam body. There is provided a vehicle bumper beam structure in which the beam body and the wing body are rigidly connected to form a single bumper beam.

  The wing body constituting the end of the bumper beam has an opening structure on the vehicle body side, and the crash box is introduced through this opening and is rigidly connected to the opposing surfaces, while the beam body has a substantially full length and a closed cross-sectional shape. Can do.

  The bumper beam end and the crush box are made of steel and are welded to each other. On the other hand, the beam main body is an aluminum extruded material, and the bumper beam end and the beam main body can be connected by bolts and nuts.

  An inner bracket that connects the inner side of the vehicle body between the beam body and the crash box or an outer bracket that connects the outer side of the vehicle body between the bumper beam end and the crash box can be provided. Can protrude somewhat backwards. Furthermore, the connection site | part of the inner bracket and outer bracket with respect to a crash box can be made into the substantially the same position in a vehicle body front-back direction.

  By dividing the bumper beam into a beam body and a wing body, it is possible to realize cost reduction while maintaining the expected performance by using a structure and material adapted to the required performance required for each part of the bumper beam.

  By connecting the crash box to the wing body of the opening structure, the crash box can be extended to the bumper beam contact surface, the crash box in the longitudinal direction of the vehicle body can be lengthened, and the collision energy by the crash box in the collision The amount of absorption can be increased, and the bending strength at the frontal collision can be ensured by the beam body having the other closed sectional structure.

FIG. 1 is a plan view of a bumper beam according to the present invention (one end is shown in cross section). FIG. 2 is a perspective view of the bumper beam according to the present invention as seen from the front (the inner bracket is shown in an exploded state). 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a schematic diagram showing the energy absorption characteristics of the bumper beam of the present invention in comparison with the prior art. FIG. 5 is a plan view (only one side is shown) of a bumper beam according to another embodiment of the present invention. 6 is a perspective view (partially shown in an exploded state) of the bumper beam of FIG. 5 as viewed from the rear.

  1 and 2, reference numeral 10 denotes a bumper beam, which is a structural member extending in the vehicle width direction. The following explanation assumes that the bumper beam is provided at the front of the vehicle body (front bumper), but the bumper beam of the present invention can also be used as a rear bumper at the rear of the vehicle body, and in the case of a rear bumper Needless to say, the explanation of is reverse to that of the front bumper.

  One end of the crash box 12 is fixed to both ends of the bumper beam 10, and the other end of each crash box 12 is fixed to the front end of each side member 14 which is a skeleton member of the vehicle body.

  In the present invention, the bumper beam 10 has a divided structure including an intermediate beam body 16 and wing bodies 18 at both ends. The beam body 16 is an aluminum extruded material in this embodiment, and has a rectangular cross section closed on the entire circumference, while the wing body 18 is a press-formed product made of a steel plate, and is inside the vehicle body (that is, in the case of a front bumper). The rear side of the vehicle body, or the front side of the vehicle in the case of the rear bumper) has a U-shaped cross-sectional shape or a hat-shaped cross-sectional shape (see FIGS. 2 and 3), slightly exceeding the crash box 12 as shown in FIG. Are arranged so as to protrude on both sides of the vehicle body. As shown in FIGS. 1 and 2, the beam main body 16 is bent at both ends somewhat toward the rear of the vehicle body (the bent portion is indicated by 16 'in FIG. 2), and each blade at the bent end portion 16'. By mounting the body 18 from the outside, the bent end portion 16 ′ is accommodated in the opening of the wing body 18 having a U-shaped cross section (FIG. 3). Needless to say, the inner diameter of the opening and the outer diameter of the wing body 18 are in a dimensional relationship that allows for a loose accommodation. The front wall 18-1 and the upper and lower walls 18-2 and 18-3 of the wing body 18 having a U-shaped cross section are connected to the opposing wall of the beam body 16 having a rectangular cross section by bolts 20 and nuts 22 (rigid connection means). Then, the beam main body 16 and the wing body 18 are rigidly connected integrally by bolting, so that a single bumper beam 10 is formed.

  In the embodiment described above, the beam body 16 is made of an extruded aluminum material. However, the beam body 16 may be formed of a steel pipe having a rectangular cross section. In this case, a single bumper beam is formed by welding connection to the wing body 18. 10 can be configured. The beam body 16 is not limited to a tube shape as long as it has a required strength.

  In FIG. 1, the crash box 12 is formed of a steel plate and has a substantially rectangular cross-sectional shape (see FIG. 1), and one end wall (front wall in the case of a front bumper) 12-1 on the side of the bumper beam 10 is closed. The end forms a flange 12-2, and the flange 12-2 is fastened to the front surface of the side member 14 with a bolt (not shown) or the like. On the side wall of the crash box 12, a plurality of concave grooves 12A are provided on the front and rear sides of the vehicle body (two locations in the figure). At the time of a collision, crushing is actively induced at the concave groove 12A portions, The crash box function of absorbing collision energy is effectively exhibited. Further, the crush box 12 has a closed end surface (12-1) side extended to an opening having a U-shaped cross section of the wing body 18, and the closed end surface 12-1 is opposed to the wall surface of the wing body 18 (in the case of a front bumper, the front wall). Wall surface) 18-1 is contacted and connected by welding (see FIG. 1). The configuration in which the closed bottom surface of the crash box 12 is extended to the rear surface opening of the wing body 18 enables the length of the crash box 12 in the longitudinal direction of the vehicle body to be as large as possible in a limited space of the vehicle body. In other words, the crushing allowance of the crash box 12 at the time of the collision can be increased, and the amount of absorbed energy can be increased.

  Reference numeral 24 denotes an inner bracket for connecting the vehicle body inner side surfaces of the beam body 16 and the crash box 12 together. The inner bracket 24 is a press product of a steel plate having bent portions 24-1, 24-2 formed at both ends, and the bent portion 24-1 at one end is an inner upright surface of the beam body 16 made of an aluminum extruded material (a front bumper of the front bumper). In this case, it is fixed to the rear wall surface 16A) with bolts 26 and nuts 27 (bolt holes are indicated by 28 in FIG. 2). The bent portion 24-2 at the other end is welded to the inner upright surface 12B of the crash box 12. In the present invention, the wing body 18 constituting both ends of the bumper beam 10 has a rear opening structure formed by a press-formed product of a steel plate, and there is a concern that the rigidity of the wing body 18 may be somewhat lowered with respect to bending applied to the bumper beam 10. For this reason, the inner bracket 24 is provided to ensure the rigidity of the wing body 18.

The characteristics of the bumper beam 10 according to the present invention with respect to the collision will be described. Assume that an obstacle installed in front of one side of the vehicle body is B (FIG. 1), and the obstacle B is moved forward with respect to the bumper beam 10 in the collision test. In FIG. 4, the horizontal axis represents the movement stroke of the obstacle B after the collision with the bumper beam 10, and the vertical axis represents the crushing load. In the present invention, the beam body 16 of the bumper beam 10 is made of an aluminum material. However, since the cross section is closed, the crushing strength (strength in the longitudinal direction of the vehicle body) can be the same as that of the crash box 12. When the stroke S ₁ is the upper limit of the elastic limit range, crushing load in this range increases linearly (line l _1). The bumper beam 10 and the crush box 12 the increase to the stroke S ₁ is started permanent deformation, the load as shown in line l ₂ is slide into proceeds substantially increased without the stroke is increasing collapse. Both of the bumper beam 10 and the crush box 12 absorbs the impact energy up to the full stroke of the fully collapsed S ₂ is performed. The integral value of the line l ₁ + l ₂ (= lower left slanted area) indicates the collision energy absorbed. This absorbed energy characteristic is equivalent to that of Patent Document 2. In the case of Patent Document 1, since the aluminum bumper beam is open on the rear surface, the crushing load is bumper beam <crash box, the elastic limit value of the bumper beam is lowered, and the elastic deformation l ₁ ′ is a smaller load value (the stroke is S ₁ ′). ), The crushing of the bumper beam continues as shown by line l ₂ ′, the crush box starts elastic deformation l ₂ ″ at the stroke S ₁ ″ where the bumper beam is completely crushed, and the crush box reaches the limit of the elastic limit. When the stroke S ₁ ″ is reached, the crash box starts to crush, which coincides with the line l _2. The energy absorption amount of the patent document 1 is the integral value of the line l ₁ ′ + l ₂ ′ + l ₂ ″ ( The area below the line shows the impact energy absorbed. That is, the absorbed energy of Patent Document 1 is smaller than the absorption amount area of Patent Document 2 by the cross hatched area. In the present invention, energy characteristics equivalent to those of Patent Document 2 can be obtained, and the bumper beam is divided into the end portion and the beam body, so that the structure and material are adapted to the required performance required for each part of the bumper beam. There is an effect that cost reduction can be realized while maintaining the expected performance.

  The length of the crash box in the longitudinal direction of the vehicle body is configured by introducing the front portion of the crash box 12 from the rear surface opening of the wing body 18 and connecting the front end surface 12-1 to the inner surface of the front wall 18-1 of the wing body 18. The collision energy absorption amount by the crash box in the collision can be increased. On the other hand, although the beam body 16 is made of aluminum, it has a closed cross section around the entire circumference, so that it is possible to secure a bending strength in a frontal collision despite being lightweight. The beam body 16 can also be constituted by a steel pipe, and in this case, it can be integrated with the wing body 18 by welding.

  The wing body 18 constituting the bumper beam by being connected to the beam body 16 can be a press-formed product of a steel plate, thereby reducing vehicle damage at the time of a collision and making the entire bumper beam a hollow product. A large bend that is sometimes not obtainable can be applied to the pressed product (as may be necessary to adapt to the shape of the outer bumper fascia, as explained in connection with the second embodiment), etc. Can increase the degree of freedom.

  5 and 6 show another embodiment, which is characterized in that an outer bracket 30 that connects the outer wall surface of the crash box 12 to the wing body 18 that is both ends of the bumper beam 10 is provided. The outer bracket 30 has a bent portion 30-1 at one end welded to the outer upright wall 12C of the crash box 12, and the outer bracket 30 extends obliquely laterally therefrom, and somewhat beyond the outer edge 18 'of the wing body 18. After extending, the bent portion 30-2 is bent to the inside, and the bent portion 30-2 is welded and fixed to the outer upright wall 18-1 of the wing body 18 of the bumper beam by the auxiliary bracket 32. In FIG. 5, F indicates a bumper fascia made of synthetic resin that is an exterior part of the bumper, and a bent portion 30-2 that is the most distal portion of the outer bracket 30 is an inner side of a bent end portion F ′ of the bumper fascia F. Is close to.

  In this embodiment, since the outer bracket 30 is positioned at the forefront with respect to the obstacle B in the offset collision test, the intrusion amount of the obstacle B at the time of the collision is reduced, and the vehicle damage is reduced. Can do. Further, since the outer bracket 30 is connected to the crash box 12, a part of the external force at the time of collision can be directly shared with the crash box 12 via the outer bracket 30.

  As shown in FIG. 5, with respect to the crash box 12, the inner bracket 24 is connected to the crash box 12 at the bent portion 24-2, and the outer bracket 30 is connected to the crash box 12 at the bent portion 30-1. The bent portions 24-2 and 30-1 are substantially at the same position in the longitudinal direction of the vehicle body. In other words, the connecting portions of the inner bracket 24 and the outer bracket 30 with respect to the crash box 12 are aligned at substantially the same position in the longitudinal direction of the vehicle body, and in order to equalize the external force applied to the crash box at the time of collision on the inside and outside, Stable crushing of the crash box can be obtained.

10 ... Bumper beam 12 ... Crash box 16 ... Beam body 18 ... Wing body
20, 22 ... Bolts and nuts connecting the beam body and wing body 24 ... Inner bracket 30 ... Outer bracket

Claims (3)

A bumper beam for a vehicle that extends in the vehicle body width direction between side members on both sides of the vehicle body and is connected to an end portion of each side member via a respective crash box. The bumper beam has both ends in the vehicle body width direction. A beam body that stays in front of the crash box, and a wing body that is formed separately from the beam body, extends outward in the vehicle body width direction from each end of the beam body, and is connected to the crash box. become, the beam body and the blade body are rigidly joined to form a single bumper beam, said blade body forms a open structure to the vehicle body, the crash box through the opening portion of the blade body blade body to be connected in the opposing faces, the beam body to name a closed cross-sectional shape substantially the full length, the blade body and the crash box as material a steel material is welded in the opposing faces and the other, Over arm body of aluminum extruded material with a material, the blade body and the beam body are connected by bolts and nuts, and the beam body and the vehicle bumper beam with an inner bracket that connects the vehicle body inner surface comrades the crash box Construction. In the invention according to claim 1 , the wing body extends beyond the end face of the crash box to the outside in the vehicle body width direction, and further includes an outer bracket for connecting the wing body and the crash box. A bumper beam structure for a vehicle that extends from the outer wall surface of the crash box beyond the edge of the wing body to the outside of the vehicle body. 3. The vehicle bumper beam structure according to claim 2 , wherein a connection portion of the inner bracket and the outer bracket with respect to the crash box is substantially at the same position in the longitudinal direction of the vehicle body.

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