JP5038098B2 - Front body structure of automobile - Google Patents

Description

  The present invention relates to a front body structure of an automobile in which an upper member is disposed above left and right side members extending in the vehicle front-rear direction so that a front end of the upper member is located behind a front end of the side member.

  In recent automobiles, there is a case where an upper member is disposed rearwardly with respect to the side member to form an arrangement space in front of the upper member, and a headlight is arranged in the arrangement space. When such a structure is adopted, if the front end of the side member is deformed upward by an input at the time of a frontal collision, there is a possibility that a so-called pitching phenomenon occurs in which the front part of the vehicle body sinks and the rear part of the vehicle body rises. It cannot be absorbed effectively.

In order to prevent the front end portion of the side member from being deformed upward, the front end portion of the upper member and the side member are coupled with a rigid member extending in the vertical direction, and the front end portion of the side member is coupled with the rigid member and the upper member. There is a case where a so-called moment canceller structure of pressing is employed (see, for example, Patent Document 1).
JP 2005-335619 A

  By the way, in the case of the conventional structure in which the side member and the upper member are firmly connected by the rigid member, the front end portion of the side member is compressed and deformed in the axial direction in the initial stage of the collision, and the side member and the upper member are shared in the middle stage of the collision. It aims to absorb the load. However, in the case of this conventional structure, the front end portion of the side member may be deformed upward in the initial stage of the collision, and there is a problem that the reduction in pitching cannot be avoided reliably.

  The present invention has been made in view of the above-described conventional situation, and it is an object of the present invention to provide a front body structure of an automobile that can reliably prevent the front end portion of a side member from being deformed upward by an input at the time of a collision. Yes.

According to a first aspect of the present invention, there is provided a side member extending in the vehicle front-rear direction, an upper member extending in the vehicle front-rear direction above the side member, and disposed so that a front end thereof is located behind the front end of the side member. A front body structure of an automobile including a reinforcing member that is coupled between the front end portion of the upper member and the side member, the side member rearing the front member portion and the rear member portion. The reinforcing member is connected via a kick portion extending obliquely downward, and the reinforcing member is a front wall portion extending obliquely forward and downward from a connecting portion to the upper member and a rear wall portion extending substantially directly below in a vehicle side view. And a lower side part connecting the lower end of the rear wall part and the front wall part, the lower side part is connected to the upper surface of the front member part, and the rear wall part is the kit. Located forward by part, the suspension member to the lower surface of the side member is attached so as to be positioned rearward of the rear wall portion,
The reinforcing member is configured to bend and deform a midway portion in the front-rear direction of the side member by rotating downward about a joint portion with the upper member by a load input at the time of a vehicle collision.

According to a second aspect of the present invention, in the front body structure of the automobile according to the first aspect,
The connecting portion between the reinforcing member and the upper member is formed to be more fragile than the peripheral portion thereof.

  According to the front body structure of the first aspect of the present invention, the reinforcing member rotates downward about the coupling portion with the upper member by the load input at the time of the vehicle collision. Is pushed downward, and along with this, the middle part of the side member in the front-rear direction is lifted upward. As a result, the entire front part of the vehicle body is lifted, and the pitching phenomenon that the front part of the vehicle body sinks and the rear part of the vehicle body rises can be suppressed.

  In the invention of claim 2, since the connecting portion between the reinforcing member and the upper member is formed weaker than the peripheral portion thereof, the reinforcing member can be easily rotated downward about the connecting portion, and the middle portion of the side member The upward bending deformation can be surely performed. In addition, the certainty of the bending deformation can be realized by a simple means of weakening the connecting portion between the reinforcing member and the upper member, and the problem of an increase in cost can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 4 are views for explaining a front body structure of an automobile according to an embodiment of the present invention. FIG. 1 is a side view of the front body frame of the automobile, and FIG. FIG. 3A to FIG. 3C and FIG. 4 are views schematically showing the behavior state of the front body frame at the time of a vehicle collision.

  In the figure, reference numeral 1 denotes a front body frame of an automobile. The front body frame 1 includes left and right side members 2 and 2 extending in the vehicle longitudinal direction, and left and right upper members 3 and 3 extending in the vehicle longitudinal direction above the left and right side members 2. The left and right reinforcing members 4 and 4 for connecting the front end portion 3b of the left and right upper members 3 and the side member 2 are provided. Here, the front body frame 1 is substantially symmetrical with respect to the vehicle body center line C.

  The front body frame 1 is disposed on the vehicle exterior side of the left and right side members 2, and extends to the left and right rocker panels 5, 5 extending in parallel with the side members 2, and the left and right side members 2. The left and right tunnel members 6, 6 that are disposed inside the vehicle and extend substantially parallel to the side member 2, the rear end portions of the left and right side members 2, the left and right rocker panels 5, and the left and right And a cross member 7 for connecting the tunnel member 6 in the vehicle width direction.

  The left and right side members 2 have a rectangular tube shape with a closed cross section, and extend in a rearward and obliquely downward direction from a front member portion 2a extending substantially linearly in the front-rear direction and from the rear end of the front member portion 2a. It has a kick part 2b and a rear member part 2c extending substantially linearly rearward from the lower end of the kick part 2b. The cross-sectional area of the kick part 2b is set smaller than the cross-sectional area of the front member part 2a.

  The left and right kick portions 2b are connected to an outer torque box 8 extending to the vehicle outer side and an inner torque box 9 extending to the vehicle inner side. A front end portion of the rocker panel 5 is coupled to an outer end portion of the outer torque box 8, and a front end portion of the tunnel member 6 is coupled to an inner end portion of the inner torque box 9.

  A hollow suspension member 10 is disposed below the kick portion 2 b of the left and right side members 2. The suspension member 10 is mounted with an engine unit (not shown) and a suspension arm (not shown) that supports the left and right front wheels 14 and 14.

  Support pipes 11, 11 are connected to the left and right front ends of the suspension member 10, and the left and right support pipes 11 are bent and extended outward in the vehicle width direction, so that the rear of the front member portion 2a. A bolt 12 is attached to the lower surface of the end. The left and right rear end portions of the suspension member 10 are attached to the lower surface of the lower end portion of the kick portion 2b by bolts 13.

  Suspension towers 15 and 15 are disposed between the front member portion 2a of the left and right side members 2 and the upper member 3, and the upper end portions of the left and right suspension towers 15 are coupled to the upper member 3 and the lower ends thereof. The part is coupled to the front member part 2a. A dash panel 16 is connected to the rear side walls of the left and right suspension towers 15, and a front edge of the floor panel 17 is connected to the lower edge of the dash panel 16.

  The left and right upper members 3 are made of a rigid body having a hat-like vertical cross section, and when viewed from the side of the vehicle, the left and right upper members 3 have a generally triangular shape whose vertical dimension decreases toward the front.

  The rear ends 3a of the left and right upper members 3 are coupled to a front pillar 18 extending in the vertical direction, and the lower ends of the left and right front pillars 18 are coupled to the rocker panel 5 (see FIG. 3). ).

  The front ends 3 ′ of the left and right upper members 3 are located behind the front ends 2 ′ of the side members 2, and are between the front ends 3 ′ of the left and right upper members 3 and the front ends 2 ′ of the side members 2. Vehicle components such as a headlight are arranged in the arrangement space formed in the above.

  The left and right reinforcing members 4 have a closed cross section and are composed of a rigid body extending in the vertical direction. When viewed from the side of the vehicle, the left and right reinforcing members 4 have a generally triangular shape whose front-rear dimension decreases toward the upper side. .

  The left and right reinforcing members 4 have apex corners 4 a coupled to the front end 3 b of the upper member 3, and the lower side 4 b coupled to the front member 2 a of the side member 2. As a result, the front portion of the front member portion 2a from the reinforcing member 4 is a crash stroke portion 2a 'that compressively deforms in the axial direction when a frontal collision occurs.

  The front wall portion 4c of the left and right reinforcing members 4 extends from the front end portion 3b of the upper member 3 so as to incline forward and downward, and the rear wall portion 4d extends from the front end portion 3b of the upper member 3 substantially directly below. Yes. Therefore, the length a of the front wall portion 4c of the reinforcing member 4 is longer than the length b of the rear wall portion 4d, and is substantially a right triangle when viewed from the side of the vehicle.

  The joint portion 20 between the apex angle portion 4a of the left and right reinforcing members 4 and the front end portion 3b of the upper member 3 is formed to be weaker or lower in strength than its peripheral portion. Specifically, the front end portion 3b of the upper member 3 has a sharp shape by cutting out a part 3b 'thereof, and the apex portion 4a is joined to the front end portion 3b having the sharp shape by welding. In this way, the connecting portion 20 is more fragile than the portion behind the front end portion 3 b of the upper member 3 and the portion below the apex angle portion 4 a of the reinforcing member 4.

  In this manner, the lower side portion of the reinforcing member 4 having a triangular shape in side view is coupled to the front member portion 2a so as to have high rigidity, and the triangular apex portion 4a is weakened to the pointed front end portion 3b. Since they are coupled, the reinforcing member 4 is rotated downward about the coupling portion 20 with the upper member 3 by a load input at the time of a frontal collision, and accordingly, the rear end portion of the front member portion 2a of the side member 2 Folds upward and deforms.

  Specifically, as shown in FIGS. 3A to 3C, the crash stroke portion 2a ′ of the front member portion 2a is compressed and deformed in the axial direction by the input at the time of a frontal collision, and the reinforcing member 4 is The front member 2a is pivoted about the connecting portion 20 in the direction of pushing down, and the front member 2a is deformed downward along with this, and the boundary portion between the rear end of the front member 2a and the kick portion 2b is formed. Bends upside down in an inverted V shape. In this case, since the upper member 3 and the reinforcing member 4 themselves are rigid bodies, the upper member 3 and the reinforcing member 4 are hardly deformed or buckled, and only the weak coupling portion 20 is mainly deformed.

  When the front member portion 2a is bent upward, a vertical load is applied to the support pipe 11 of the suspension member 10, so that the support pipe 11 is broken and detached from the side member 2. When the bending of the front member portion 2a is further increased, a force from the engine or transmission is also applied, the left and right rear end portions of the suspension member 10 are broken, and the entire suspension member 10 is dropped.

  On the other hand, as the front member portion 2a bends upward and the reinforcing member 4 further rotates and the front wall portion 4c becomes substantially vertical, the front member portion 2a sends the input to the front pillar 18 in the direction of arrow c. To act on.

  Since the front member portion 2a of the side member 2 is pushed downward by the reinforcing member 4 in this way, the suspension member 10 drops off almost simultaneously with the collision, and the crash stroke of the vehicle body can be earned. As a result, the engine unit including the suspension member 10 can be prevented from entering the indoor side.

  Further, when the front member portion 2a is pushed downward, the peripheral portion of the front pillar 18 is lifted up. As a result, the entire front part of the vehicle body is lifted, and the front part of the vehicle body sinks, so that the pitching phenomenon that the rear part of the vehicle body rises is suppressed. As a result, as shown in FIG. 4, the anchor 25 of the seat belt device that restrains the occupant to the seat can be prevented from moving forward, the anchor 25 can be held in the locked position, and the restraint performance of the occupant can be improved. It can be secured. That is, as shown in FIG. 5, when the rear portion of the vehicle body is lifted due to the pitching phenomenon, the anchor 25 is moved forward by x from the lock position in accordance with the lift. In some cases, the seat belt that restrains the occupant moves in a loosening direction, which may affect the restraint performance of the occupant.

  As described above, according to the present embodiment, the reinforcing member 4 is configured to rotate downward around the coupling portion 20 with the upper member 3 by a load input at the time of a frontal collision. At the same time, the front member 2a is pressed downward, and the rear end of the front member 2a is lifted upward. As a result, it is possible to suppress the sinking of the front part of the vehicle body and further to lift up, thereby suppressing the pitching phenomenon that the rear part of the vehicle body is lifted, and the suspension member 10 can be dropped off almost instantaneously.

  In the present embodiment, since the connecting portion 20 between the reinforcing member 4 and the upper member 3 is formed weaker than the rigidity and strength of the reinforcing member 4 and the upper member 3 which are the peripheral portions thereof, the reinforcing member 4 connects the connecting portion 20. It becomes easy to rotate to the center, and the suppression of the pitching phenomenon can be realized by a simple means of weakening the coupling portion 20, and an increase in cost can be avoided.

  In the present embodiment, since the length a of the front wall portion 4c of the reinforcing member 4 is made longer than the length b of the rear wall portion 4d, the front member portion 2a can be more reliably pressed down at the time of collision. And the pitching phenomenon can be more reliably suppressed. Here, it is possible to adjust the pitching amount by changing the ratio of the length a of the front wall portion 4c to the length b of the rear wall portion 4d in accordance with the size and dimensions of the front vehicle body.

  In the above-described embodiment, the case has been described in which the coupling portion 20 is formed to be fragile by notching a part 3b ′ of the front end portion 3b of the upper member 3. However, various modifications are included in the weakening in the present invention. Can be considered. For example, the plate thickness of the connecting portion may be thinner than other portions, the welding amount of the connecting portion may be less than other portions, or the connecting portion may be bolted or hinged, or the upper member or reinforcing member A reinforcing bead or the like may be added to a portion other than the coupling portion, thereby relatively reducing the rigidity and strength of the coupling portion.

1 is a side view of a front body frame of an automobile according to an embodiment of the present invention. It is a top view of the said front body frame. It is a schematic diagram which shows the deformation | transformation state of the front body frame by the said embodiment. It is a schematic diagram which shows the suppression effect of the pitching phenomenon of the vehicle body by the said embodiment. It is a schematic diagram which shows the pitching phenomenon of a general vehicle body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front body frame 2 Side member 2 'Front end 3 Upper member 3' Front end 3b Front end 4 Reinforcement member 20 Joint part

Claims (2)

A side member extending in the vehicle front-rear direction, an upper member extending in the vehicle front-rear direction above the side member, and having a front end disposed behind the front end of the side member; and a front end portion of the upper member; A front vehicle body structure of an automobile provided with a reinforcing member that is bridged and coupled between the side members,
The side member is formed by connecting the front member portion and the rear member portion via a kick portion extending obliquely downward and rearward.
The reinforcing member is connected to the front wall portion extending obliquely forward and downward, the rear wall portion extending substantially directly below, and the lower ends of the rear wall portion and the front wall portion from the connecting portion to the upper member in a vehicle side view. Has a generally triangular shape with a lower side to
The lower side portion is connected to the upper surface of the front member portion, and the rear wall portion is located in front of the kick portion,
The suspension member is attached to the lower surface of the side member so as to be located behind the rear wall portion,
The automobile is characterized in that, by a load input at the time of a vehicle collision, the reinforcing member pivots downward about a coupling portion with the upper member, thereby bending and deforming a midway portion in the front-rear direction of the side member. Front car body structure. The front body structure of an automobile according to claim 1,
A front vehicle body structure of an automobile, wherein a joint portion between the reinforcing member and the upper member is formed to be weaker than a peripheral portion thereof.

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