JP2010006233A - Vehicle body frame structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide vehicle body frame structure can accurately generate an effective drag for absorbing energy at an initial stage of collision and a later stage of collision with a short stroke. <P>SOLUTION: The region at the chip end side on a cylindrical extension side frame 10 having a closed cross section structure is set as a first energy absorption region 12, and recessed parts 13a, 13b extending to the peripheral direction are formed at key points of the first energy absorption region 12. Meanwhile, on the extension side frame 10, the region continued at the base end side of the recessed part 13a is provided on a peripheral edge of the base end part of the first energy absorption region 12 is set as a second energy absorption region 15, and this second energy absorption region 15 is formed to be a skirt spreading cylindrical shape having a peripheral length increasing from the chip end side toward the base end side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cylindrical body frame structure having a closed cross-sectional structure.

  In general, a vehicle body frame such as a front side frame or a rear side frame of a vehicle has a configuration in which an impact acting in the extending direction of the vehicle body frame at the time of a vehicle collision is absorbed mainly by crushing an energy absorption region set at a front end portion. ing.

  In this case, in the energy absorption region, it is required to start crushing with a relatively small load at the initial stage of the collision in order to mitigate the impact given to the occupant. On the other hand, in order to efficiently absorb the collision energy with a short stroke, it is required to maintain a predetermined drag continuously after the crushing is once started.

In order to realize different shock absorption modes in the initial stage and the second half of the collision as described above, for example, Patent Document 1 discloses that the first bead is entirely disposed on the front end side of the front frame having a rectangular closed cross section extending in the longitudinal direction of the vehicle body. A technique in which uneven portions that are formed in the front and back are formed by a plurality of second beads extending in the circumferential direction of the front frame on both the left and right plane portions that continue to the rear of the first bead while being formed over the circumference. It is disclosed. According to such a technique, in the initial stage of the collision, the initial maximum strength (drag) is reduced by crushing the front frame triggered by the deformation of the first bead, and in the latter half of the collision, the deformation of each second bead is reduced. As a result, the front frame is crushed, so that it is possible to maintain a predetermined drag while preventing the front frame from buckling.
Japanese Patent No. 3840788

  However, the technique disclosed in Patent Document 1 described above has a configuration in which the vehicle body frame is crushed by the deformation of each bead (second bead) even in the second half of the collision, and thus sufficiently high drag is generated in the region. Has its limits.

  Therefore, the technique disclosed in Patent Document 1 described above requires a certain amount of stroke in order to increase the energy absorption amount in the second half of the collision, and it may still be difficult to sufficiently shorten the energy absorption region. It was.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle body frame structure capable of accurately generating effective drag for energy absorption in the initial stage of collision and the latter half of collision with a short stroke.

  The present invention provides a vehicle body frame structure in which an energy absorption region for absorbing an impact at the time of a vehicle collision is set to a cylindrical tip region having a closed cross-sectional structure, and the energy absorption region is a convex extending in a circumferential direction. A first energy absorption region having at least a base portion or a recess formed at the base end portion, and a base end portion of the first energy absorption region, and the peripheral length is changed from the front end side to the base end side. And a second energy absorption region having a flared shape.

  According to the vehicle body frame structure of the present invention, it is possible to accurately generate a drag effective for energy absorption in the early and late collisions with a short stroke.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a perspective view showing a schematic configuration of a front part of a vehicle body, FIG. 2 is a perspective view showing a schematic configuration of an extension side frame, and FIG. 3 is a side view showing details of the extension side frame. FIG. 4 is an explanatory diagram showing the transition of the extension side frame during crushing, and FIG. 5 is an explanatory diagram schematically showing the shock absorption characteristics of the extension side frame.

  In FIG. 1, reference numeral 1 denotes a vehicle body such as an automobile, and front side frames (vehicle body frames) 2 extending in the front-rear direction are respectively disposed on the left and right front portions of the vehicle body 1. In the present embodiment, each front side frame 2 has, for example, a front side frame main body 5 and an extension side frame 10 fixed to a front end portion of the front side frame main body 5 to constitute a main part. Yes.

  A bracket 7 integrally provided with a radiator panel side 6s is fixed to the front end portion of the front side frame body 5. A radiator panel upper 6u extending in the vehicle width direction is connected to the upper end portion of the radiator panel side 6s, and a radiator panel lower 6l extending in the vehicle width direction substantially parallel to the radiator panel upper 6u is connected to the lower end portion. It is connected.

  The extension side frame 10 is formed of, for example, a cylindrical member having a closed cross-sectional structure, and a base end portion is fastened and fixed to the front side frame main body 5 via a bracket 7. On the other hand, a bumper beam 20 extending in the vehicle width direction is fixedly provided at the distal end portion (front end portion) of the extension side frame 10. The extension side frame 10 functions as a so-called crash box, and the extension side frame 10 is fixed to the front side frame body 5 so that it extends in the extending direction of the front side frame 2 at the time of a frontal collision of the vehicle. An energy absorption region 11 for absorbing the acting impact by crushing is formed in the front end region (front end region) of the front side frame 2.

  The region on the front end side on the extension side frame 10 is set as a first energy absorption region 12 for absorbing the impact input through the bumper beam 20 or the like by crushing mainly at the beginning of the collision at the time of a frontal collision of the vehicle. Has been.

  Specifically, as shown in FIGS. 2 and 3, the first energy absorption region 12 is formed, for example, with a parallel cylindrical shape having the same peripheral length as a basic shape. A plurality of recesses extending in the circumferential direction are formed at the essential points of the first energy absorption region 12, and the drag that can be generated in the first energy absorption region 12 due to the recesses in the circumferential direction is, for example, an extension It is limited to about 80% of the maximum drag that can be generated on the side frame 10.

  Here, the number and arrangement of the recesses formed in the first energy absorption region 12 can be appropriately set based on experiments, simulations, and the like, but at least the first energy as shown in the figure. A recess 13 a is formed at the base end of the absorption region 12. In this embodiment, this recessed part 13a is comprised by the bead-shaped recessed part, for example, and is formed over the perimeter of the 1st energy absorption area | region 12. As shown in FIG. In the present embodiment, for example, a recess 13b extending a predetermined length in the vertical direction (circumferential direction) of the first energy absorption region 12 is formed on the tip side of the recess 13a. In the first energy absorption region 12, a convex portion extending in the circumferential direction can be formed as a drag adjusting means instead of the concave portions 13a and 13b described above. However, in consideration of the ease of manufacture, stability of the shock absorption mode, and the like, the drag adjusting means is preferably a concave portion rather than a convex portion.

  Further, a region on the extension side frame 10 that is continuous to the base end side of the first energy absorption region 12 is input to the front side frame 2 through the bumper beam 20 or the like mainly in the second half of the collision at the time of a vehicle front collision or the like. It is set as a second energy absorption region 15 for absorbing an impact by crushing.

  More specifically, as shown in FIGS. 2 and 3, the second energy absorption region 15 has a cylindrical shape with a skirt that changes so that the circumference increases from the distal end side to the proximal end side. It is formed as a basic shape. In the present embodiment, the peripheral length (minimum peripheral length) of the distal end portion of the second energy absorption region 15 is set to be longer than the peripheral length (maximum peripheral length) of the first energy absorption region 12. Moreover, the circumference of the base end part of the 2nd energy absorption area | region 15 is set so that it may become about 10% longer than the circumference of a front-end | tip part, for example.

  Here, the 2nd energy absorption area | region 15 becomes a structure which does not have the circumferential recessed part (or circumferential convex part) which may become an obstacle in improving a drag. Instead, in the second energy absorption region 15, in the range not exceeding the drag that can be generated on the front side frame body 5 side, in order to improve the drag due to the ridge line effect, from the front end side to the base end direction. An extending recess is appropriately formed as necessary. As shown in FIGS. 2 and 3, in the present embodiment, in the second energy absorption region 15, bead-shaped recesses 16 extending from the front end side to the base end side are provided on the inner and outer side walls in the vehicle width direction. Is formed. In the second energy absorption region 15, it is also possible to form a convex portion extending from the distal end side to the proximal end side as a drag adjusting means instead of the aforementioned concave portion 16. However, in consideration of the ease of manufacture, stability of the shock absorption mode, and the like, the drag adjusting means is preferably a concave portion rather than a convex portion.

  In such a configuration, an impact input through the bumper beam 20 or the like at the beginning of a collision such as a frontal collision of the vehicle is absorbed mainly by crushing the first energy absorption region 12. That is, the first energy absorption region 12 starts to be crushed with a relatively small load, triggered by deformation in the recesses 13a and 13b extending in the circumferential direction. Thereby, the impact input to the front side frame 2 in the initial stage of writing is absorbed by the first energy absorption region 12 (see FIG. 4B and FIGS. 5A and 5B).

  Then, in the latter half of the collision after the impact absorption is performed in the first energy absorption region 12, the impact input to the front side frame 2 is absorbed by the crushing of the second energy absorption region 15. That is, as described above, the second energy absorption region 15 has a cylindrical shape with a hem that changes so that the circumference increases from the distal end side to the proximal end side. Since the recess 13a is provided immediately before, the load in the direction in which the wall is pushed and bent acts on the second energy absorption region 15, and the second energy absorption region 15 has the wall inward. Crushing sequentially from the tip side while rolling. And since the 2nd energy absorption area | region 15 is crushed in this way, when the 2nd energy absorption area | region 15 is crushed, a high drag is continuously maintained, and the impact input to the front side frame 2 in the second half of the collision is And efficiently absorbed by the second energy absorption region 2 (see FIG. 4C and FIGS. 5A, 5B, and 5B). In FIG. 5 (a), the shock absorption characteristic when the second energy absorption region is formed in a parallel cylindrical shape is indicated by a one-dot chain line.

  In this case, since the second energy absorption region 15 has a cylindrical shape with an expanded bottom, buckling and the like in the middle are accurately suppressed. Furthermore, if a recess 16 or the like extending from the distal end side to the proximal end side is formed in the second energy absorption region 15, buckling or the like in the second energy absorption region 15 is more accurately due to the ridge line effect or the like. And the drag generated during crushing is improved. In addition, by setting the peripheral length of the tip of the second energy absorption region 15 to be equal to or longer than the peripheral length of the first energy absorption region 12, the wall portion can be crushed when the second energy absorption region 15 is crushed. It is possible to accurately achieve the inward entrainment.

  According to such an embodiment, a region on the distal end side on the cylindrical extension side frame 10 having a closed cross-sectional structure is set as the first energy absorption region 12, and the key points of the first energy absorption region 12 are set. By forming the recesses 13 a and 13 b extending in the circumferential direction, the maximum drag that can be generated in the first energy absorption region 12 can be limited. Thereby, the 1st energy absorption area | region 12 can start crushing by a comparatively small load, and can absorb the impact input mainly at the beginning of a collision exactly. On the other hand, on the extension side frame 10, a region continuous to the base end side of the recess 13 a provided around the base end portion of the first energy absorption region 12 is set as the second energy absorption region 15, and the second energy absorption region 15 is set. By forming the energy absorption region 15 in a cylindrical shape having a skirt that increases in circumference from the distal end side to the proximal end side, the wall portion of the second energy absorption region 15 can be crushed while being wound inwardly. it can. Thereby, when the second energy absorption region 15 is crushed, a high drag can be continuously maintained, and an impact input in the latter half of the collision can be efficiently absorbed. Accordingly, energy can be efficiently absorbed with a short stroke. Thus, by realizing sufficient energy absorption with a short stroke, for example, shock absorption at the time of a light collision or the like can be performed only by crushing the energy absorption region 11. When completed, parts replacement at the time of repair can be kept to a minimum.

  In the above-described embodiment, an example in which the present invention is applied to the front side frame 2 has been described. However, the present invention is not limited to this, and can be applied to, for example, a rear side frame. is there.

The perspective view which shows schematic structure of a vehicle body front part The perspective view which shows schematic structure of an extension side frame Side view showing details of extension side frame Explanatory drawing showing the transition of the extension side frame during crushing Explanatory drawing schematically showing the impact absorption characteristics of the extension side frame

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle body 2 ... Front side frame 5 ... Front side frame main body 6l ... Radiator panel lower 6s ... Radiator panel side 6u ... Radiator panel upper 7 ... Bracket 10 ... Extension side frame 11 ... Energy absorption area 12 ... First energy absorption area 13a, 13b ... concave portion 15 ... second energy absorption region 16 ... concave portion 20 ... bumper beam

Claims (2)

A vehicle body frame structure in which an energy absorption region for absorbing a shock at the time of a vehicle collision is set in a cylindrical tip region having a closed cross-sectional structure,
The energy absorption region includes a first energy absorption region in which a convex portion or a concave portion extending in the circumferential direction is formed at least at a base end portion;
And a second energy absorption region that is connected to the base end portion of the first energy absorption region and has a hem-spread shape that changes so that the circumference increases from the tip end side to the base end side. Body frame structure.   The vehicle body frame structure according to claim 1, wherein the second energy absorption region has a convex portion or a concave portion extending in the proximal direction from the distal end side.

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