JP4506499B2 - Front body structure of automobile - Google Patents

Description

  The present invention relates to a front body structure of an automobile, and more specifically, to a front body structure of an automobile provided with a shock absorbing box at a front end portion of a front side frame.

  Conventionally, in order to mitigate the impact at the time of a frontal collision of an automobile, a cylindrical shock absorbing box (so-called crash can) is provided at the front end of the front side frame extending in the vehicle front-rear direction, and this shock absorbing box is seated at the initial stage of the collision. What absorbs an impact by bending and deforming is known.

  This shock absorbing box is generally located on the vehicle rear side of a bumper reinforcement that is a bumper reinforcement member, and is set to buckle and deform as the bumper retreats.

  Further, when the shock absorbing performance is further enhanced, it is also known to install a second shock absorbing box on the front side of the bumper reinforcement because the shock absorbing box alone is not sufficient.

  For example, in Patent Document 1 below, an impact absorption box (Crashbox 2 in the document) is provided on the rear side of the bumper reinforcement, and a second shock absorption box (Vorcrashbox 10 in the document) is installed in front of the bumper reinforcement. An automobile front body structure is disclosed.

German Patent Application Publication No. 10143890 (FIG. 4, FIG. 5)

  By the way, the above-mentioned second shock absorption box of Patent Document 1 has a substantially pentagonal shape in plan view with a top portion set at the front end.

  In this second shock absorbing box, the top is set at the front end, while avoiding the urethane foam member installed at the center in the vehicle width direction, the curved surface of the bumper face corner at the end in the vehicle width direction This is to avoid it.

  However, in the case of the shock absorbing box of Patent Document 1, since the corners are located on both sides other than the top of the front end, it cannot be predicted what deformation state will occur when a frontal collision occurs.

  That is, in the case of the second shock absorbing box, the corner portion which is a free end other than the top portion is bent at a predetermined angle on both sides, so that the deformation state changes depending on which corner portion is bent. It is.

  Thus, if the deformation state cannot be predicted, it is difficult to set the transmission direction of the collision load to a certain direction, and the collision load is appropriately applied to the main shock absorbing box located on the rear side of the bumper reinforcement. May not be able to be transmitted, and impact absorption may not be performed properly.

  Accordingly, the present invention provides a vehicle body structure for a front part of an automobile in which a second shock absorbing box is disposed on the front side of the vehicle while the shock absorbing box is disposed on the rear side of the bumper reinforcement. The front body of an automobile is configured to properly transmit the impact load to the main shock absorbing box and properly absorb the shock by defining the deformation state of the shock absorbing box at the time of the frontal collision. The purpose is to provide a structure.

  The vehicle front body structure of the present invention includes a pair of left and right shock absorbing boxes provided at the front end of the front side frame, and a front end portion of the left and right shock absorbing boxes extending in the vehicle width direction in front of the shock absorbing box. Bumper reinforcement that bridges the vehicle, and a second shock absorbing box provided on the front surface of the bumper reinforcement at a position substantially coinciding with the shock absorbing box in the vehicle width direction. The second shock absorbing box includes an inner wall inclined toward the vehicle center and an outer wall inclined toward the vehicle side, and a front end formed by the inner wall and the outer wall. The top part of the outer wall is set to be located on the vehicle center side, and the outer end part of the outer wall is directly joined to the bumper reinforcement, and the inner wall is deformed when a load is received from the front of the vehicle. Brittle Part one in which a is provided.

  According to the above configuration, the second shock absorbing box includes the inner wall and the outer wall, and the top portion of the front end formed by the inner wall and the outer wall is positioned on the vehicle center side, whereby the vehicle When receiving a load from the front, it becomes easier to deform toward the inner wall. Then, by joining the outer end of the outer wall directly to the bumper reinforcement and providing the weakened portion on the inner wall, the inner wall is deformed with the outer end of the outer wall as a fulcrum.

  For this reason, the second shock absorbing box can make the deformed state constant by causing the inner wall to undergo a constant buckling deformation with the outer end portion of the outer wall serving as a fulcrum during a frontal collision.

  Here, the fragile portion includes a long hole extending in the vertical direction, a notch, a thin wall portion, and the like, and can be any structure that can be easily deformed by receiving a load from the front of the vehicle. There may be.

  Also, the shock absorbing box and the second shock absorbing box should be set so that the second shock absorbing box is more easily deformed so that the second shock absorbing box is reliably deformed at the beginning of the collision. Is desirable.

  Furthermore, in addition to the inner wall and the outer wall, the second shock absorbing box may be provided with an upper wall constituting the upper surface and a lower wall constituting the lower surface, only the inner wall and the outer wall. It is not limited to what comprises.

  In one embodiment of the present invention, the weakened portion is a vertically folded bead provided in the vicinity of the middle portion of the inner wall.

  According to the above configuration, the inner wall is bent and deformed by the vertically bent beads in the vicinity of the middle portion of the inner wall when receiving a load from the front of the vehicle.

For this reason, the inner wall is surely bent and deformed at the position of the vertically folded bead, and the deformation state of the second shock absorbing box can be made more reliable.
Therefore, the deformation state of the second shock absorbing box can be defined more reliably.

  In one embodiment of the present invention, the vertically folded bead is an internally folded bead that is recessed inside the second shock absorbing box.

  According to the above configuration, the inner wall is bent and deformed inside the shock absorption box when receiving a load from the front of the vehicle.

  For this reason, the bending point of an inner wall can be set to at least two places of a top part and an inner folding bead part, and it can be made more than one place of an inner folding bead part when bent outside.

  Therefore, the shock absorption performance of the second shock absorption box can be enhanced, and the shock absorption performance can be further enhanced.

  In one embodiment of the present invention, the second shock absorbing box is formed by bending a developed flat plate, and includes an inner wall and upper and lower walls of the second shock absorbing box. Are provided with gaps between the inner wall and the upper and lower walls at the front and rear positions of the inner bead.

  According to the said structure, a 2nd shock absorption box is comprised by bending a flat plate, and it connects in the front-back position of an inner folding bead, providing a clearance gap between the inner wall and an up-and-down wall. It will be composed.

  For this reason, the second shock absorbing box has the upper and lower walls to secure the rigidity as the box body and connects the upper and lower walls and the inner wall only at the front and rear positions of the inner bead. The rigidity does not act on the bending deformation, and the inner wall is reliably deformed at the time of frontal collision.

  Therefore, while increasing the normal rigidity of the second shock absorbing box, the inner wall can be reliably bent and deformed at the time of a frontal collision, and the shock absorbing performance of the second shock absorbing box can be improved.

  In one embodiment of the present invention, the bumper reinforcement is configured with a U-shaped cross section that is open on the vehicle rear side, the second shock absorbing box is attached to the front surface of the vertical wall of the bumper reinforcing member, and the bumper The shock absorbing box is attached to the rear surface of the vertical wall of the reinforcement.

  According to the above configuration, the front end portion of the shock absorbing box extends to the inside of the bumper reinforcement, and the second shock absorbing box is positioned in front of the bumper reinforcement.

  For this reason, the shock absorbing box that mainly absorbs the shock can be set long without being affected by the front-rear width of the bumper reinforcement.

  Therefore, the shock absorption amount of the shock absorption box can be increased, and the shock absorption performance can be further enhanced.

  In one embodiment of the present invention, the shock absorbing box is formed with a flange portion extending in the front-rear direction protruding in the horizontal direction, and the cross-section of the bumper reinforcement at the center position in the vehicle width direction is constituted by a square-shaped cross section. However, the bumper reinforcement cross section corresponding to the front position of the flange portion is formed by a U-shaped cross section.

  According to the said structure, by providing the flange part which protruded in the horizontal direction in the shock-absorbing box, at the time of a frontal collision, a shock-absorbing box will raise a shock-absorbing load and will buckle and deform | transform. And, by setting the center position of the bumper reinforcement to a B-shaped cross section, the bumper reinforcement becomes a closed cross section and can improve rigidity, but at the position corresponding to the flange portion, the U-shaped cross section As a result, even if the bumper reinforcement retreats at the time of a frontal collision, the bumper reinforcement does not interfere with the flange portion and reliably retreats.

  For this reason, the second shock absorbing box can make the deformed state constant by causing the inner wall to undergo a constant buckling deformation with the outer end portion of the outer wall serving as a fulcrum during a frontal collision.

  Therefore, the buckling deformation of the shock absorbing box can be more reliably performed while increasing the rigidity of the bumper reinforcement.

  According to this invention, in the case of a frontal collision, the second shock absorbing box can be deformed constant by buckling deformation of the inner wall with the outer end portion of the outer wall as a fulcrum.

  Therefore, in the vehicle front body structure in which the second shock absorbing box is disposed on the front side of the vehicle while the shock absorbing box is disposed on the rear side of the bumper reinforcement, the second shock absorbing box is provided. It is possible to reliably define the deformation state at the time of a frontal collision, and it is possible to appropriately transmit the impact load to the main shock absorbing box and appropriately absorb the shock.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a transparent front view of an automobile adopting the front vehicle body structure of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG. 4 is a cross-sectional view taken along the line CC of FIG.

  The front vehicle body structure of the present embodiment includes a pair of left and right front side frames 1 and 1 that extend in the vehicle front-rear direction, a pair of left and right main crash cans 2 and 2 that are fastened and fixed to the front end of the vehicle and forward of the vehicle. The bumper reinforcement 3 that extends in the vehicle width direction and is joined and fixed to the front end portions of the left and right main crash cans 2, 2, the urethane foam material 4 installed at the front center portion of the bumper reinforcement 3, and the bumper Pre-crash cans 5 and 5 installed at positions corresponding to the main crush cans 2 and 2 on both front sides of the reinforcement 3, and the vehicle so as to cover the front surfaces of the foamed urethane material 4 and the pre-crash cans 5 and 5. And a bumper face 6 provided at the front end.

  In addition, the cross member that extends in the vehicle width direction between the front side frames 1 and 1 and connects the left and right front side frames 1 and 1 and the suspension tower that supports the suspension device also constitute the front body structure. Since there is no direct relationship with the present invention, illustration and description are omitted.

  The aforementioned front side frames 1 and 1 are constituted by a frame member having a closed cross-sectional shape extending in parallel with a pair of left and right in the longitudinal direction of the vehicle.

  In front portions of the front side frames 1, 1, bulge portions 11, 11 that bulge upward are formed so as to appropriately receive the collision load transmitted from the main crash cans 2, 2. Further, fastening flanges 12 and 12 for fastening and fixing the main crash cans 2 and 2 are joined and fixed to the front end portions of the front side frames 1 and 1 so as to protrude outward.

  The aforementioned main crush cans 2 and 2 are formed of a cylindrical member having a substantially hexagonal cross section. Specifically, as will be described later, the upper and lower surfaces and the side surfaces of the main crash cans 2 and 2 are processed to promote buckling deformation.

  Fastening flanges 21 and 21 projecting outward corresponding to the fastening flanges 12 and 12 of the front side frames 1 and 1 are also joined and fixed to the rear end portions of the main crash cans 2 and 2.

  The bumper reinforcement 3 described above includes a member member 31 having a U-shaped cross-section with an open rear surface, and a plate member 32 having a square-shaped cross-section by closing the open surface at the center in the vehicle width direction. It consists of and.

  The bumper reinforcement 3 has a bowed center at the front so as to increase the front-rear width of the central portion in the vehicle width direction, thereby increasing the rigidity of the central portion. Further, by providing two grooves 33, 33 extending in the vehicle width direction on the front surface 3a, the rigidity of the central portion is further increased, so that bending deformation does not easily occur even with a collision load from the front. It is configured.

With this configuration, at the time of a frontal collision, both ends of the bumper reinforcement 3 are reliably retracted, and the collision load can be reliably transmitted to the left and right main crash cans 2 and 2.
Reference numeral 34 denotes a tie-down hook locking hole for engaging the tie-down hook.

  The foamed urethane material 4 described above is installed across the vehicle width direction and the vertical direction at the center position in front of the bumper reinforcement 3. This foamed urethane material 4 is installed to absorb the impact of light collision and to ensure the surface rigidity of the bumper face 6.

  The aforementioned bumper face 6 is installed over the entire vehicle width direction at the front end of the vehicle. As shown in FIG. 1, the radiator grilles 61 and 62 for introducing outside air into the engine room are opened at the center and the lower part. In addition, head lamp openings 63 and 63 for mounting the headlamps are formed in the upper left and right positions, and auxiliary lamp openings 64 and 64 for mounting the auxiliary lamps are formed in the left and right positions in the center.

  The aforementioned pre-crash cans 5 and 5 are made of box-shaped members having a substantially triangular shape in plan view, and are joined to the vehicle width direction position corresponding to the installation position of the main crush cans 2 and 2 on the front surface 3a of the bumper reinforcement 3. is doing.

  The pre-crash cans 5 and 5 are provided in order to effectively absorb a load that cannot be sufficiently absorbed by the main crush cans 2 and 2 alone in the case of a front offset collision.

  Specific structures of the pre-crash can 5 and the main crush can 2 will be described with reference to FIGS. 5 is a detailed plan view of the vicinity of the left pre-crash can, FIG. 6 is a detailed side view thereof, FIG. 7 is a perspective view of the vicinity of the pre-crash can viewed from the center front of the vehicle, and FIG. It is the perspective view of the pre-crash can vicinity seen from.

  The pre-crash can 5 has an inner wall 52 inclined toward the vehicle center from the top 51 at the front end and an outer wall 53 inclined toward the vehicle side, and the top 51 at the front end is located on the vehicle center side. It is set as follows.

  The pre-crash can 5 is provided with a substantially triangular upper wall 54 and a lower wall 55 formed by bending from the outer wall 53 on the upper and lower surfaces, respectively, and the upper wall 54 is joined to the upper surface of the bumper reinforcement 3. A joining flange 54a is provided.

  In this embodiment, the angle α of the top 51 formed by the inner wall 52 and the outer wall 53 is set to about 90 °, and the angle of the corner formed by the inner wall 52 and the front surface 3a of the bumper reinforcement 3 is set. β is set to about 60 °, and the angle γ formed by the outer wall 53 and the front surface 3a of the bumper reinforcement 3 is set to about 30 °. This angle is set to such a value in consideration of the assemblability of the pre-crash can 5 and the like, but is not limited to this value.

  The pre-crash can 5 is configured by bending a flat plate-shaped iron plate that has been unfolded, and by joining joining pieces 56 and 57 extending from an upper wall 54 and a lower wall 55 to an inner wall 52. The box shape has a substantially triangular prism shape.

  The joining pieces 56 and 57 are joined to the inner wall 52 by providing gaps S at front and rear positions sandwiching an inner bead 58 described later. For this reason, even if the upper wall 54 and the lower wall 55 are joined to the inner wall 52 via the joining pieces 56, 57, the joining strength does not increase so much, and it is easily separated at the time of a frontal collision and absorbs shock. The possibility of adversely affecting performance can be eliminated.

  Further, an inner bent bead 58 that extends in the vertical direction and is recessed toward the inner side of the pre-crash can 5 is formed at an intermediate portion of the inner wall 52. The inner fold bead 58 is a starting point of bending deformation when a predetermined load is applied from the front. By providing the inner fold bead 58, the pre-crash can 5 is defined as described later. Buckling deformation is likely to occur.

  Further, a circular opening hole 59 is formed in the outer wall 53. The opening hole 59 does not directly improve the shock absorbing performance, but is formed to reduce the weight.

  The thus configured pre-crash can 5 is joined to the front surface 3 a of the bumper reinforcement 3 by the joining flange 54 a of the upper wall 54 and the outer end 53 a of the outer wall 53.

  On the other hand, the main crush can 2 is composed of a cylindrical member having a hexagonal cross section as described above, and the upper surface 22a, the lower surface 22b, and the side surface 23 are processed to promote buckling deformation.

  First, on the upper surface 22a and the lower surface 22b, two fragile recesses 24 extending in the vehicle width direction, which are recessed inward of the main crush can 2, are formed. By providing the fragile recesses 24, when a collision load is applied from the front, bending deformation occurs from the fragile recesses 24 as a starting point, and bellows-like buckling deformation is surely generated.

  Further, two buckling flanges 25, 25 that extend horizontally in the vehicle front-rear direction and are joined to each other are provided on the side surface 23. The buckling flanges 25 and 25 are provided to increase the shock absorbing load, and the front side 1/3 is not provided in order to promote buckling in the initial stage of the collision.

  The buckling flanges 25, 25 are also wavy at the side edges so that they are easily deformed when a load is applied from the front.

  The front end portion 26 of the main crush can 2 is joined and fixed to the back surface 3b of the vertical wall of the bumper reinforcement 3 via a joint portion 27 (see FIG. 8).

  For this reason, the main crash can 2 can be extended to a more forward position, and the collapse length of the main crash can 2 can be increased without being affected by the front-rear width of the bumper reinforcement 3.

  Therefore, even if the front-rear distance between the bumper reinforcement 3 and the front side frame 1 is short, the length of the front-rear width of the bumper reinforcement 3 is effectively used to buckle and deform the main crash can 2. Therefore, the impact absorption performance can be further improved.

  As described above, the rear end portion 28 of the main crush can 2 is joined so as to project the fastening flange 21 outward, and the fastening flange 12 of the front side frame 1 is connected to the fastening flange 12 via four fastening bolts 29. Fastened and fixed.

  In addition, the folding | returning part 21a (refer FIG. 5, FIG. 8) to the front of the outer end of the fastening flange 21 is set in order to improve the surface rigidity of the fastening flange 21. FIG.

  As shown in FIG. 8, the plate member 32 is joined to the rear surface of the bumper reinforcement 3, but the plate member 32 is joined to the front position corresponding to the buckling flange 25. Not. That is, the bumper reinforcement 3 has a substantially rectangular cross section at the center position in the vehicle width direction, but has a substantially U-shaped cross section with the rear opening at a portion corresponding to the buckling flange 25 of the main crush can 2.

  This is because the buckling flange 25 is caught by the plate member 32 of the bumper reinforcement 3 when the main crash can 2 is buckled and deformed as will be described later, and the bumper reinforcement 3 is sufficiently retracted. In order to avoid such a problem that it becomes impossible, such a joining position is set.

  Next, the deformation state of the front vehicle body structure of this embodiment at the time of a frontal collision will be described using the deformation schematic diagram of FIG.

  9A shows the normal state before the collision in the vicinity of the front end of the front side frame, FIG. 9B shows the deformation state in the initial stage of the collision, and FIG. 9C shows the deformation state in the middle stage of the collision. (D) shows the deformation state in the latter half of the collision. In addition, about each component, the code | symbol mentioned above is attached | subjected and description is abbreviate | omitted.

  First, in the state before the collision, as shown in (a), the main crush can 2, the bumper reinforcement 3 and the pre-crash can 5 are respectively installed in front of the front side frame 1 in the positional relationship described above. Yes. X is a collision object.

  When a frontal collision, particularly an offset collision occurs, the top 51 of the pre-crash can 5 rotates backward with the outer end 53a of the outer wall 53 as a fulcrum, as shown in FIG. The side wall 52 is buckled and deformed so that it is folded inward from the bead 58.

  In this deformed state, the outer end 53 a of the outer wall 53 is directly joined to the bumper reinforcement 3, the top 51 is set on the vehicle center side, and an inner bead 58 is provided on the inner wall 52. This occurs almost certainly when a load is input from the front of the vehicle.

  Next, at the middle of the collision, as shown in (c), the pre-crash can 5 is completely deformed, the bumper reinforcement 3 is also retracted, and the main crush can 2 starts buckling deformation.

  At this time, in order to sufficiently function the shock absorbing performance of the pre-crash can 5, it is desirable to set the main crush can 2 to be deformed with a higher collision load than the pre-crash can 5.

  By causing buckling deformation in the main crash can 2, the collision load is alleviated and transmitted to the front side frame 1 and the vehicle body member behind the front side frame 1.

  The buckling deformation of the main crash can 2 is caused almost by receiving a load from the front side of the vehicle. However, since the deformation state of the pre-crash can 5 is defined to be constant, the buckling deformation occurs almost certainly. Become.

  Thereafter, at the later stage of the collision, as shown in (d), the bumper reinforcement 3 further moves backward, and not only the pre-crash can 5 but also the main crash can 2 is completely buckled.

  Thus, the bumper reinforcement 3 is deformed to the position of the front end portion of the front side frame 1, whereby the pre-crash can 5 and the main crash can 2 are completely deformed, and the collision load can be completely absorbed.

  At this time, as described above, since the plate member 32 of the bumper reinforcement 3 is set at a position avoiding the buckling flanges 25, 25, the bumper reinforcement 3 can be sufficiently retracted. The impact absorbing performance of the main crash can 2 can be obtained with certainty.

  In this way, in this embodiment, by defining the deformation state of the pre-crash can 5 to be constant, the input direction of the collision load with respect to the main crush can 2 can be made constant, so that the buckling deformation of the main crush can 2 is also ensured. Therefore, the shock absorbing performance of the pre-crash can 5 and the main crush can 2 can be completely obtained.

  Therefore, according to this embodiment, the impact absorption by the pre-crash can 5 and the main crush can 2 can be performed appropriately.

  In particular, since the inner wall 52 is set to be deformed by the inner folding bead 58, the bending deformation can be made at two locations, the top 51 and the inner folding bead 58. Absorption performance can be further enhanced.

  Further, since the plate member 32 of the bumper reinforcement 3 is also merely joined to the center of the vehicle, the bumper reinforcement 3 can also be used as a buckling space for the main crash can 2 and the impact of the main crash can 2 can be achieved. Absorption performance can be improved effectively.

  Next, another embodiment will be described with reference to FIGS. In this figure, only the pre-crash can is shown, and the other components are the same as those in the above-described embodiment.

  First, the (i) pre-crash can 105 is formed by forming a long hole 158 extending in the vertical direction in the middle portion of the inner wall 152 instead of the inner bead 58 of the above-described embodiment.

  Thus, since the rigidity of the intermediate portion of the inner wall 152 is relatively reduced by forming the long hole 158, when a collision load is input from the front, the bending deformation is started from the long hole 158. Arise.

  Thereby, like the above-mentioned embodiment, fixed buckling deformation | transformation arises in the pre-crash can 105. FIG.

  Therefore, also in this embodiment, by defining the deformation state of the pre-crash can 105 to be constant, the input direction of the collision load to the main crush can 2 can be made constant, so that the buckling deformation of the main crush can 2 is also ensured. Therefore, the shock absorbing performance of the pre-crash can 105 and the main crush can 2 can be completely obtained.

  In particular, in the present embodiment, since the long hole 158 is used, the pre-crash can 105 can be configured to be lightweight, and the weight of the vehicle body at the front portion of the vehicle can be reduced.

  Next, (b) pre-crash can 205 is formed by forming notch slits 258 extending in the vertical direction in the middle portion of the inner wall 252 respectively.

  In this way, by forming the notch slit 258, the rigidity of the inner wall 252 is also relatively lowered in this case, so when a collision load is input from the front, the notch slit 258 is used as a starting point. Bending deformation occurs.

  Therefore, also in this embodiment, a constant buckling deformation occurs in the pre-crash can 205, and the input direction of the collision load with respect to the main crush can 2 can be made constant. The shock absorbing performance of 2 can be completely obtained.

  Also. By using the notch slit 258, the weight of the vehicle body can be reduced.

  Finally, the (c) pre-crash can 305 has a thin portion 358 (range indicated by hatching) extending in the vertical direction at the intermediate portion of the inner wall 352.

  As described above, by forming the thin portion 358, the rigidity of the intermediate portion is relatively lowered in this case as well, so that bending deformation occurs from the thin portion 358 as a starting point. .

  Therefore, even in this embodiment, a constant buckling deformation occurs in the pre-crash can 305, and the shock absorbing performance of the pre-crash can 305 and the main crush can 2 can be completely obtained.

  Further, since the thin portion 358 is used, since there is no sudden change in rigidity as compared with the case where a notch or the like is provided, buckling deformation can be caused more smoothly during buckling deformation.

  Other functions and effects are the same as those in the above-described embodiment.

As described above, in the correspondence between the configuration of the present invention and the above-described embodiment,
The shock absorbing box of the present invention corresponds to the main crash can 2 of the embodiment,
Similarly,
The second shock absorbing box corresponds to the pre-crash cans 5, 105, 205, 305,
The weak part corresponds to the inner bead 58, the long hole 158, the notch slit 258, the thin part 358,
The vertical fold bead corresponds to the inner fold bead 58,
The flange portion corresponds to the buckling flange 25,
The present invention is not limited to the above-described embodiment, but includes an embodiment applied to the front body structure of any automobile.

The permeation | transmission front view of the motor vehicle which employ | adopted the front part vehicle body structure which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a sectional view taken along line B-B in FIG. 2. The CC sectional view taken on the line of FIG. A detailed plan view of the vicinity of the left pre-crash can. The detailed side view of the pre-crash can vicinity. The perspective view of the pre-crash can vicinity seen from the vehicle center front side. The perspective view of the pre-crash can vicinity seen from the diagonally rear side above a vehicle. The deformation | transformation schematic diagram of this embodiment. The perspective view which showed the pre-crush can of other embodiment.

Explanation of symbols

1 ... Front side frame 2 ... Main crash can (shock absorbing box)
3 ... Bumper reinforcement 5,105,205,305 ... Pre-crash can (second shock absorption box)
51 ... Top 52 ... Inner wall 53 ... Outer wall 58 ... Inner bead (fragile part)
158 ... Long hole (fragile part)
258 ... Notch slit (fragile part)
358 ... Thin part (fragile part)

Claims (6)

A pair of left and right shock absorbing boxes provided at the front end of the front side frame, a bumper reinforcement extending in the vehicle width direction in front of the shock absorbing box and bridging the front ends of the left and right shock absorbing boxes, and the bumper A front body structure of an automobile comprising a second shock absorption box provided at a position substantially coincident with the shock absorption box in the vehicle width direction on the front surface of the reinforcement,
The second shock absorbing box includes an inner wall inclined toward the vehicle center and an outer wall inclined toward the vehicle side,
The top of the front end formed by the inner wall and the outer wall is set to be located on the vehicle center side,
While joining the outer end of the outer wall directly to the bumper reinforcement,
A front body structure of an automobile in which a fragile portion that deforms when receiving a load from the front of the vehicle is provided on the inner wall. The front body structure of an automobile according to claim 1, wherein the weakened portion is a vertically folded bead provided in the vicinity of an intermediate portion of the inner wall. The front body structure of an automobile according to claim 2, wherein the vertically folded bead is an internally folded bead that is recessed inside the second shock absorbing box. The second shock absorbing box is configured by bending a flat plate that has been unfolded,
4. The front portion of an automobile according to claim 3, wherein a gap is provided between the inner wall and the upper and lower walls of the second shock absorbing box, and the inner wall and the upper and lower walls are connected at the front and rear positions of the inner bead. Body structure. The bumper reinforcement is configured with a U-shaped cross-section with an opening on the vehicle rear side,
Attaching the second shock absorbing box to the front surface of the vertical wall of the bumper reinforcing member,
The front vehicle body structure according to claim 1, wherein the shock absorbing box is attached to a rear surface of a vertical wall of a bumper reinforcement. In the shock absorbing box, a flange portion extending in the front-rear direction protruding in the horizontal direction is formed,
While configuring the cross section of the bumper reinforcement at the center position in the vehicle width direction with a square-shaped cross section,
The front vehicle body structure according to claim 5, wherein the bumper reinforcement corresponding to the front position of the flange portion has a U-shaped cross section.

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