JP3632654B2 - Body front structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle body front structure.
[0002]
[Prior art]
As a countermeasure against a collision of the vehicle, the collision energy is absorbed by axially crushing the side member at the front part of the vehicle body. For example, Japanese Patent Application Laid-Open No. 2001-158377 shows the structure of the vehicle body front part.
[0003]
This vehicle body front structure promotes axial crushing and absorbs collision energy when an axial input acts on the side member by arranging a bead on the wall of the front side member having a polygonal cross section. It is what I did.
[0004]
[Problems to be solved by the invention]
However, in such a conventional vehicle body front structure, energy can be satisfactorily absorbed with respect to a collision load that is input to the side member in the axial direction. It tends to be a deformation mode in which the front part is bent from the base part.
[0005]
Therefore, the collision energy at the time of the oblique collision is only temporarily absorbed by the bending of the front portion of the side member, and it becomes difficult to obtain a load characteristic that continuously absorbs the collision load by axial crushing.
[0006]
For this reason, in order to obtain sufficient impact energy absorption characteristics only by bending the front part of the side member, it is necessary to significantly increase the rigidity of the side member, so that the thickness of the side member inevitably increases. As a result, there is a concern that the vehicle weight will increase significantly.
[0007]
Therefore, the present invention is a vehicle body front structure that can reliably crush and deform the front end portion of the side member against a collision load input from obliquely forward as well as from the front direction, and can improve collision energy absorption efficiency. Is to provide.
[0008]
[Means for Solving the Problems]
In the first aspect of the invention, the left and right sides of the front compartment are provided with reinforcing portions for mounting vehicle unit parts on the side members arranged in the longitudinal direction of the vehicle body, and the vehicle width extends across the front ends of these side members. In the front structure of the vehicle body that combines the bumper reinforcement extending in the direction,
A side member front region that is forward from the reinforcing portion of the side member is formed to be inclined outward in the vehicle width direction toward the front of the vehicle body, and the side member front region that is opened outwardly from the front end in the longitudinal direction . When taking a cross section perpendicular to the longitudinal direction intermittently toward the rear, the maximum stress generated at the front and rear of each cross section is the strength of the state where the front is greater than or near the rear. In addition, the side member is sequentially crushed and deformed from the front by the collision load input from the front in the vehicle width direction inner portion than the connecting portion of the bumper reinforcement with the side member. upon interference reinforcement, interfere with the side surface center portion of the side member is characterized in that a reaction force adjustment means for suppressing the increase of the reaction force of the side members That.
[0009]
According to a second aspect of the present invention, in the vehicle body front part structure according to the first aspect, the reaction force adjusting means has a bumper reinforcement having a sectional height of the bumper reinforcement, and a cross-section of the side member in the vicinity of the connecting portion of the side member. It is formed as a height-increasing portion that is substantially equal to or higher than the height, and is formed as a height-decreasing portion that is smaller than the cross-sectional height of the side member at a portion that is a predetermined distance away from the connecting portion of the side member. It is characterized in that the reduced portion is configured to correspond to the center of the side surface avoiding the ridgeline of the side member.
[0010]
According to a third aspect of the present invention, in the vehicle body front part structure according to the first aspect, the reaction force adjusting means has a bumper reinforcement whose cross section height is substantially equal to or greater than the cross section height of the side member. The bumper reinforcement is provided with a protrusion having a width smaller than the cross-sectional height of the side member on the rear surface of the bumper reinforcement at a predetermined distance from the connecting portion of the side member, and the protrusion avoids the ridgeline of the side member. It is characterized by being arranged corresponding to the center of the side surface.
[0011]
【The invention's effect】
According to the first aspect of the present invention, the side member front region that is forward from the reinforcing portion is formed to incline outward in the vehicle width direction toward the front of the vehicle body, and the side member front region is strength-adjusted. When a cross section perpendicular to the longitudinal direction is intermittently taken from the front end in the longitudinal direction of the side member front region to the rear by means, the maximum stress generated in the front and rear of each cross section is Is set to a strength that is greater than or close to the rear, or even if a collision load is input to the front end of the side member from either the front direction or diagonally forward, the front side of the side member that is the input point of the collision load Crushing deformation is induced from the front end of the region toward the rear, and the crushing deformation is continuously propagated to the rear part of the side member front region, so that the efficiency of absorbing collision energy can be increased.
[0012]
At this time, the front region of the side member is crushed and deformed including the ridge line of the closed cross section, and as the crushing deformation progresses, it gradually interferes with the rear surface of the bumper reinforcement, but the bumper reinforcement is provided with reaction force adjusting means. Therefore, since the reaction force adjusting means can suppress an increase in the reaction force of the side member, the deformation of the side member can be promoted and efficient energy absorption can be performed.
[0013]
According to the invention of claim 2, in addition to the effect of the invention of claim 1, the reaction force adjusting means is used as a height change portion of a bumper reinforcement in which a height increasing portion and a height decreasing portion are formed. Since the height reduction part is made to correspond to the center part of the side surface avoiding the ridgeline of the side member, the deformation mode of the side member front area by the collision load input from the front is initially the side member front area. Interfering with the height increasing portion, the entire cross section including the rigid ridgeline of the side member having a closed cross section is crushed and deformed. As the crushing deformation progresses, the side member becomes the height decreasing portion. The side member front region is deformed starting from the side surface with low rigidity, and can be easily deformed while suppressing an increase in reaction force.
[0014]
According to the invention of claim 3, in addition to the effect of the invention of claim 1, the reaction force adjusting means has a required portion on the rear surface of the bumper reinforcement in which the cross-sectional height is formed substantially equal to or higher than that of the side member. In addition, a protrusion having a width smaller than the cross-sectional height of the side member is provided, and this protrusion is arranged so as to correspond to the center of the side surface avoiding the ridgeline of the side member. The deformation mode of the front region of the side member by the first is that the front region of the side member interferes with the bumper reinforcement whose cross section height is increased, and the entire cross section including the rigid ridgeline of the side member that has become a closed cross section is deformed. However, as the crushing deformation progresses, the side member interferes with the protruding portion, and the front region of the side member starts to be deformed from the side having low rigidity, and the reaction force increases. The suppressing deformation can be easily performed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
(First embodiment)
1 to 11 show a first embodiment of a vehicle body front structure according to the present invention, FIG. 1 is an external perspective view of an automobile targeted by the present invention, and FIG. 2 is a schematic diagram showing a skeleton structure on the right side of the vehicle front section. FIG. 3 is a perspective view of the front region of the side member, FIG. 4 is an enlarged cross-sectional view taken along the line AA in FIG. 3, and FIG. 5 is an input configuration model (a) and a stress distribution diagram. FIG. 6 is an explanatory diagram shown in (b), FIG. 6 is a stress distribution diagram showing the concept of strength adjusting means, and FIG. 7 shows the deformation modes of the side member front region by the reaction force adjusting means in order by (a) to (c). FIG. 8 is an explanatory diagram showing a bumper reinforcement molding method. FIG. 9 is an end perspective view of another bumper reinforcement molding method (a), BB line cross section (b), CC line. Explanatory drawing shown by the cross section (c), FIG. 10 is provided with a reaction force adjusting means of the bumper reinforcement There structures (a) and provided a structure (b) and illustration comparatively showing, FIG. 11 is a graph comparing the reaction force of the side members due to the presence or absence of the reaction force adjustment means.
[0017]
The vehicle body front structure of the present embodiment is applied to the front compartment F / C of the vehicle body 10 shown in FIG. 1, and the skeleton structure is a side member 11 disposed in the vehicle body front-rear direction on the left and right sides as shown in FIG. The general portions of the side members 11 are arranged in parallel, and bumper reinforcements 12 forming a skeleton of a bumper (not shown) are coupled across the front end portions of the side members 11.
[0018]
Further, an extension side member 13 that extends from the dash panel 17 to the lower surface side of the floor panel 18 is connected to the rear side of each side member 11, and the extension side member 13 is substantially outward in the vehicle width direction. Side sills 14 are arranged in parallel, and the front end portions of the extension side member 13 and the side sill 14 are connected by an outrigger 15.
[0019]
A dash cross member 16 is coupled across the connecting portions of the side members 11 and the extension side members 13.
[0020]
A suspension arm 21 that supports the front wheel 20 is attached to the rear side of the side member 11 directly or via a suspension member (not shown), and an engine or the like as a vehicle unit component is provided between the left and right side members 11. The power unit 30 is mounted via a mount bracket 31.
[0021]
As shown in FIG. 3, the side member 11 is provided with a reinforcing portion 11 </ b> R (shown as a satin portion in FIG. 3) where the thickness of the side member 11 is increased at the mounting portion of the mount bracket 31.
[0022]
That is, as shown in FIG. 3, the side member 11 has a closed cross-sectional structure by fixing both side flange portions of the U-shaped second plate 11b to the flat plate strip-shaped first plate 11a by spot welding or the like. The reinforcing portion 11R is formed by joining and arranging a reinforcing plate on the inner peripheral surface.
[0023]
Here, in this embodiment, as shown in FIG. 3, the side member front region 11 </ b> F forward from the reinforcing portion 11 </ b> R of the side member 11 is moved in the vehicle width direction toward the front of the vehicle body (front side in FIG. 3). Inclined outward (leftward in FIG. 3) by a predetermined angle θ.
[0024]
Then, in the side member front region 11F that is open outwardly, as shown in FIG. 3, sections Ia, Ib... Ie that are intermittently orthogonal to the longitudinal direction from the front end in the longitudinal direction to the rear are provided. When taken, the maximum stress generated at the front and rear of each cross section (hereinafter referred to as a virtual cross section) is such that the front is greater than or equal to the rear (front ≧ rear) or close to this strength. A side member plate thickness changing structure 50 is configured as strength adjusting means, and the plate thickness distribution of the side member front region 11F is changed in the longitudinal direction.
[0025]
That is, as shown in FIG. 4, the side member plate thickness changing structure 50 has plate thicknesses t1, t2, t3... T6 (t1 <t2 <t3 <... <t6) stepwise from the front end direction of the side member front region 11F. A plurality of changing plate members 51a, 51b, 51c,... 51f are constituted by a composite panel member 52 joined by welding all around, and the plate member 51f having the largest thickness is the reinforcing portion 11R.
[0026]
Further, when the collision load F from the front acts on the front end of the side member front region 11F as shown in FIG. Sum of axial force component stress (FY / A (y)) and moment component stress ({FX × (L−y)} / Z (y)) generated in each virtual section Ia, Ib... Ie (see FIG. 3). Is set to be the front portion≈the rear portion, and the upper limit value is set to the yield strength σ (y) of the side member constituting material.
[0027]
σ (y) = {FY / A (y)} + {FX × (L−y)} / Z (y) Equation 1
At this time, the upper limit value of the maximum stress due to the side member plate thickness changing structure 50 is set based on the yield strength of the material constituting the side member 11 as described above. As a result, as shown in FIG. , 51b, 51c... 51f, yield strength σ (y) is obtained.
[0028]
Incidentally, since the side member front region 11F is inclined outward in the vehicle width direction as shown in FIG. 3, the collision load F from the front direction is applied as shown in FIGS. By inputting, the side member 11 is sequentially crushed and deformed from the front, and as the crushing deformation progresses, the side member 11 interferes with the rear surface of the bumper reinforcement 12. A height changing portion 60 is provided as a reaction force adjusting means that suppresses an increase in the reaction force of the side member 11 when a certain amount of interference has progressed.
[0029]
The height changing portion 60 has a height-increasing portion 61 (the height of the cross section of the bumper reinforcement 12 is approximately equal to or greater than the cross sectional height h0 of the side member 11 in the vicinity of the connecting portion C with the side member 11). The cross-section height h1) is a height that is smaller than the cross-section height h0 of the side member 11 at a portion that is a predetermined distance inward (rightward in FIG. 3) from the connecting portion C with the side member 11. It is formed as a reduced portion 62 (cross-sectional height h2), and this height reduced portion 62 is configured to correspond to the side surface central portion 11e avoiding the ridge lines 11c and 11d of the side member 11.
[0030]
The height changing portion 60 formed in the bumper reinforcement 12 crushes the upper and lower surfaces of the bumper reinforcement 12 having a hollow closed cross-section structure, for example, by press molding using hydraulic pressure as shown in FIG. Thus, the height decreasing portion 62 is formed, and the height decreasing portion 62 and the height increasing portion 61 are connected to each other with the stepped portion 63 as a boundary.
[0031]
In addition, the height changing portion 60 is provided with a bumper reinforcement 12 as shown in FIG. 9B, and a partition plate 64 at the upper and lower portions of the closed cross-section so that the cross-sectional shape is an eye shape. It is also formed by extruding into a shape with a light alloy material and cutting the upper and lower surfaces corresponding to the height reducing portion 62 by machining as shown in FIGS. 9 (a) and 9 (c). Can do.
[0032]
Further, the height changing portion 60 has various methods other than the hydraulic forming in FIG. 8 and the machining of the light alloy extruded material in FIG. 9. For example, the height changing portion 60 is formed along the final cross-sectional shape at the time of extrusion forming. It can also be formed by a variable cross-section light alloy extruded material.
[0033]
(Function)
According to the vehicle body front portion structure of the first embodiment having the above configuration, when a static collision load F acts on the front end portion of the front side member 11 from the front as shown in FIG. As described above, the axial force component stress (FY / A (y)) and the moment component stress ({FX × (Ly)} generated in the virtual cross sections Ia, Ib... Ie continuous in the longitudinal direction of the side member front region 11F. / Z (y)) has a maximum value of the front part≈back part, and the upper limit value is the yield strength σ (y) of the side member constituent material. The front end of the front side member 11 that is the input point reaches the yield region of the material and plastic deformation occurs. As a result, when the collision load F is input, the side member front region 11F is separated from the front end that is the input point. Inducing crushing deformation (collapse) In addition, the crushing deformation is deformed in a mode in which the crushing deformation is continuously propagated rearward, so that the collision energy can be reliably absorbed.
[0034]
At this time, as described above, the side member front region 11F is formed to incline outward in the vehicle width direction toward the front of the vehicle body. However, the side member front region 11F can be continuously crushed and deformed from the tip.
[0035]
Further, the front end portion of the side member 11 can be disposed further outward in the vehicle width direction by the side member front region 11F inclined in the vehicle width direction outward in this manner. It can be expanded in the width direction.
[0036]
Here, as described above, the side member front region 11F can be continuously crushed and deformed from the front end side toward the rear with respect to the frontal collision, but the strength rigidity is high in the vicinity of the reinforcing portion 11R. Therefore, the reaction force inevitably increases.
[0037]
However, according to the structure of this embodiment, the ridgelines 11c and 11d (FIG. 3) in which the side member front region 11F has a closed cross section as shown in FIG. 7B from the state of FIG. If the crushing deformation K including the crushing deformation K progresses and the rear surface 12a of the bumper reinforcement 12 sequentially interferes with the progress of the crushing deformation K, and the interference point moves to the rear of the vehicle with the progress of the crushing deformation K, the bumper It is possible to suppress the reaction force of the front side member 11 from increasing in the latter half of the crushing deformation K by the height changing portion 60 of the reinforcement 12.
[0038]
That is, since the height reducing portion 62 of the height changing portion 60 is arranged corresponding to the side surface central portion 11e (see FIG. 3) avoiding the ridge lines 11c and 11d of the front side member 11, the crushing deformation K When the side central portion 11e of the side member front region 11F interferes with the height reducing portion 62 as the travel proceeds, the side member front region 11F starts to deform from the side surface 11e having low rigidity as shown in FIG. Thus, it is possible to suppress the increase of the reaction force and promote the crushing deformation K to allow efficient energy absorption.
[0039]
FIG. 11 shows the reaction force characteristic P of the side member 11 when the bumper reinforcement 12 in which the height changing portion 60 is not formed as shown in FIG. 10A, and as shown in FIG. 10B. The reaction force characteristic Q of the side member 11 in the case of using the bumper reinforcement 12 of the present embodiment in which the height changing portion 60 is formed is shown in comparison with the side member front region 11F as time elapses. As the interference portion between the bumper reinforcement 12 and the bumper reinforcement 12 increases, a large reaction force reduction region can be secured in the reaction force characteristic Q in the latter half portion where the height reduction portion 62 is provided.
[0040]
Therefore, the crushing deformation K when the side member front region 11F interferes with the bumper reinforcement 12 can be positively performed, and as a result, the energy of the collision load F by the side member 11 can be efficiently absorbed.
[0041]
In the first embodiment, the height changing portion 60 as the reaction force adjusting means only needs to be processed so as to change the cross-sectional heights h1 and h2 of the bumper reinforcement 12, so that the reaction force adjusting means The overall structure can be simplified.
[0042]
By the way, in this embodiment, the said side member board thickness change structure 50 is made into the board thickness t1, t2, t3 ... t6, and several board | plate material 51a, 51b, 51c ... 51f from which board thickness differs in step thickness. Since the composite panel material 52 joined so as to change is formed, the maximum stress generated in the virtual cross sections Ia, Ib... Ie continuous in the longitudinal direction of the side member front region 11F is approximately controlled, and the side member The crushing deformation K from the front end portion of the front region 11F can be induced without hindrance, and the formation of the side member front region 11F can be facilitated.
[0043]
Further, since the side member plate thickness changing structure 50 is thus a cross-sectional dimension changing structure in which the cross-sectional dimension of the side member front region 11F is changed in the longitudinal direction, the collision load F is applied to the front end portion of the side member 11. , The maximum stress generated in the virtual cross section continuous in the longitudinal direction of the side member front region can be easily controlled, and the strength balance can be easily adjusted, and the front end of the side member front region 11F at the time of collision The crushing deformation K from the part can be induced more reliably.
[0044]
The number of the plate members 51a, 51b, 51c,... 51f is not limited to this embodiment, and the number may be determined according to the required crushing characteristics of the side member front region 11F.
[0045]
Further, in the side member plate thickness changing structure 50, the maximum stress generated at the front and rear of the virtual cross section of the side member front region 11F is set to be front ≈ rear. May be set to a strength that is greater than or equal to the rear portion, that is, the front portion ≧ the rear portion or a state close thereto.
[0046]
(Second Embodiment)
12 to 15 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted.
[0047]
12 is a schematic plan view showing the skeleton structure on the right side of the front part of the vehicle body, FIG. 13 is a rear perspective view showing the main part of the bumper reinforcement, and FIG. 14 is an enlarged sectional view taken along the line DD in FIG. FIG. 15 is a plan view showing a deformed state of the side member front region.
[0048]
The vehicle body front part structure of the second embodiment is configured by a projection 70 provided with a reaction force adjusting means on the rear surface of the bumper reinforcement 12 as shown in FIGS.
[0049]
In the second embodiment, the bumper reinforcement 12 has a cross-sectional height h1 formed in advance that is substantially equal to or greater than the cross-sectional height h0 of the side member, and a predetermined distance from the connecting portion C of the side member 11 of the bumper reinforcement 12. The protrusion 70 having a width h3 smaller than the cross-sectional height h0 of the side member 11 is provided on the rear surface close to the inner side of the vehicle, and the protrusion 70 is connected to the ridge line 11c of the side member 11 as in the first embodiment. 11d is arranged to correspond to the side surface central portion 11e.
[0050]
The projection 70 is formed as a channel material bent in a U-shaped cross section as shown in FIG. 14, and both end flanges 71 and 71a are continuously welded to the center in the height direction of the rear surface 12a of the bumper reinforcement 12. Are joined by. Of course, the protrusion 70 has sufficient rigidity to crush and deform the front side member 11 when it interferes with the front side member 11.
[0051]
Accordingly, even in the second embodiment, similarly to the first embodiment, as shown in FIG. 15, the side member front region 11F is input by the input of the collision load F from the front direction or the collision load F1 from the oblique front. In the deformation mode, first, the side member front region 11F interferes with the bumper reinforcement 12 having a larger section height h1, and the entire section including the ridge lines 11c and 11d of the front side member 11 having a closed section is crushed and deformed K. Give rise to
[0052]
Then, as the crushing deformation K progresses, the front side member 11 interferes with the protrusion 70, and the deformation starts from the side surface 11e with low rigidity of the side member front region 11F. An increase in the reaction force can be suppressed and deformation can be promoted, and the same effect as in the first embodiment can be achieved.
[0053]
The reaction force adjusting means simply forms the sectional height h1 of the bumper reinforcement 12 to be substantially equal to or higher than the sectional height h0 of the front side member 11, and only adds a protrusion to the rear surface 12a of the bumper reinforcement 12. Therefore, the configuration can be simplified without complicated processing of the bumper reinforcement 12.
[0054]
By the way, although the vehicle body front part structure of the present invention has been described by taking the first and second embodiments as an example, embodiments having other configurations can be taken without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an automobile targeted by the present invention.
FIG. 2 is a schematic plan explanatory view showing a skeleton structure on the right side of the front portion of the vehicle body in the first embodiment of the present invention.
FIG. 3 is a perspective view of a front region of a side member in the first embodiment of the present invention.
4 is an enlarged sectional view taken along line AA in FIG. 3;
FIGS. 5A and 5B are explanatory diagrams showing an intensity adjustment means in the first embodiment of the present invention with an input form model (a) and a stress distribution diagram (b). FIGS.
FIG. 6 is a stress distribution diagram showing the concept of strength adjusting means in the first embodiment of the present invention.
FIGS. 7A to 7C are explanatory views sequentially showing the deformation modes of the front side member region by the reaction force adjusting means in the first embodiment of the present invention, according to (a) to (c). FIG.
FIG. 8 is an explanatory diagram showing an example of a bumper reinforcement molding method according to the first embodiment of the present invention.
FIG. 9 is an explanatory view showing another forming method of the bumper reinforcement according to the first embodiment of the present invention by an end perspective view (a), a cross section taken along line BB (b), and a cross section taken along line CC (c). .
FIG. 10 is an explanatory view showing a comparison between a structure (a) provided with no bumper reinforcement reaction force adjusting means and a provided structure (b) in the first embodiment of the present invention.
FIG. 11 is a graph comparing side member reaction forces with and without reaction force adjusting means in the first embodiment of the present invention.
FIG. 12 is a schematic plan explanatory view showing a skeleton structure on the right side of the front portion of the vehicle body in the second embodiment of the present invention.
FIG. 13 is a rear perspective view showing a main part of a bumper reinforcement in a second embodiment of the present invention.
14 is an enlarged sectional view taken along line DD in FIG.
FIG. 15 is a schematic plan view illustrating a deformed state of a side member front region in the second embodiment of the present invention.
[Explanation of symbols]
F / C Front compartment 10 Car body 11 Side member 11F Side member front area 11R Reinforcement part 11c, 11d Ridge line 11e Side surface center part 12 Bumper reinforcement 12a Rear surface 30 Power unit (vehicle unit part)
50 Side member thickness change structure (strength adjusting means)
60 Height change part (Reaction force adjustment means)
61 Height increasing portion 62 Height decreasing portion K Crushing deformation Ia, Ib ... Ie Virtual section

Claims (3)

Reinforced parts for mounting vehicle unit parts are provided on the side members arranged in the longitudinal direction of the vehicle body on the left and right sides of the front compartment, and the bumper reinforcement that extends in the vehicle width direction across the front ends of these side members is connected In the vehicle body front structure,
A side member front region that is forward from the reinforcing portion of the side member is formed to be inclined outward in the vehicle width direction toward the front of the vehicle body, and the side member front region that is opened outwardly from the front end in the longitudinal direction . When taking a cross section perpendicular to the longitudinal direction intermittently toward the rear, the maximum stress generated at the front and rear of each cross section is the strength of the state where the front is greater than or near the rear. In addition, the side member is sequentially crushed and deformed from the front by the collision load input from the front in the vehicle width direction inner portion than the connecting portion of the bumper reinforcement with the side member. upon interference reinforcement, interfere with the side surface center portion of the side member, characterized in that a reaction force adjustment means for suppressing the increase of the reaction force of the side members Body front structure. The reaction force adjusting means forms the bumper reinforcement with a cross-sectional height as a height-increasing portion that is substantially equal to or higher than the cross-sectional height of the side member in the vicinity of the connecting portion of the side member, and a predetermined distance from the connecting portion of the side member. Only the portion closer to the inner side of the vehicle is formed as a height-reduced portion smaller than the cross-sectional height of the side member, and the height-reduced portion is configured to correspond to the center of the side surface avoiding the ridgeline of the side member. The vehicle body front part structure according to claim 1. The reaction force adjusting means is formed on the rear surface of the bumper reinforcement, which has a sectional height substantially equal to or greater than the sectional height of the side member, and is located a predetermined distance from the side member connecting portion of the bumper reinforcement. 2. The projection according to claim 1, wherein a projection having a width smaller than a cross-sectional height of the side member is provided, and the projection is arranged so as to correspond to a central portion of the side surface avoiding the ridge line of the side member. Car body front structure.

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