JP3767097B2 - Front body structure of the vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle front body structure including a front side frame.
[0002]
[Prior art]
Conventionally, as a front body structure of this type of vehicle, a structure in which a front frame is constituted by a so-called double hat type frame is known (see, for example, Japanese Patent Laid-Open No. 7-70093). In this case, a pair of panels having a hat-like cross-sectional shape are faced to each other and their flanges are joined to each other, thereby forming a front frame having a rectangular cross-sectional shape. In addition, in this case, a bellows bead is formed in a predetermined range in the front-rear direction on the front end side of the front frame, and irregularities are formed alternately. On the other hand, a predetermined crushing deformation is caused.
[0003]
In addition, the front frame used in the front body structure of the vehicle needs to support the engine and suspension and resist the collision load from the front. In general, a rectangular surface shape is used (see, for example, US Pat. No. 3,912,295). In addition, when the front frame is formed in a rectangular shape using a hat-shaped panel, the vehicle width of the flange to be joined is made the same size and shape with respect to the substantially entire length in the front-rear direction. There is also known one in which the direction position is shifted in the front-rear direction to change the position (see, for example, US Pat. No. 4,133,549).
[0004]
[Problems to be solved by the invention]
By the way, the front body of the vehicle has a collision load from the front due to a frontal collision, a collision load from a slanting front due to a so-called offset collision, or a collision load from various directions such as a collision load from the side where the encounter occurs. May act. For this reason, when the front vehicle body is constituted by a front frame, it is necessary to take measures against the collision loads from the various directions described above.
[0005]
However, the above-described front frame is required to conflict with the rigidity of each front and rear part. For example, since it is necessary to support the suspension on the rear end side of the front frame, it is necessary to suppress the swinging (bending) around the vehicle width direction axis against the external force in the vertical direction input from the suspension or the like. There is. Therefore, it is necessary to increase the cross-sectional rigidity with respect to the vehicle width direction axis on the rear end side of the front frame. On the other hand, it is necessary to be able to withstand collision loads from various directions as described above on the front end side of the front frame. Furthermore, at this time, although the front frame is compressed in the front-rear direction by absorbing the collision energy from the front by absorbing the collision energy from the front, the collision load from the oblique front due to the offset collision is received. If the front end of the front frame bends and deforms in the vehicle width direction, a situation may occur in which the collision energy cannot be absorbed by the longitudinal compression described above. In addition, it is necessary to suppress bending in the vehicle width direction against a collision load from the side. Therefore, in order to prevent bending deformation in the vehicle width direction, it is necessary to increase the cross-sectional rigidity with respect to the vertical axis on the front end side of the front frame.
[0006]
On the other hand, if the cross-sectional area is increased in order to increase the cross-sectional rigidity of the front frame, the vehicle weight increases, which is against the request for weight reduction.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to support a request for a front end portion of a front side frame at the time of a collision, a suspension, and the like while achieving weight reduction. The purpose is to satisfy both the above requirements for the rear end side of the front side frame.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is based on the front body structure of a vehicle including a pair of front side frames extending in the front-rear direction and disposed at both left and right positions in the front portion of the vehicle. The cross-sectional shape of each front side frame is changed with respect to the front-rear direction. In other words, the aspect ratio, which is the ratio of the vertical dimension in the vertical direction to the horizontal dimension in the vehicle width direction, approaches 1 as it advances from the rear part in which the vertical dimension is set to a vertically long cross-sectional shape longer than the horizontal dimension to the front end side. In such a configuration , the longitudinal dimension is maintained substantially constant from the rear part to the front end part, and the lateral dimension is formed so as to increase further outward in the vehicle width direction as it advances toward the front end part. Is. Each front side frame has an upper flange portion and a lower flange portion, and the upper flange portion is positioned so as to extend linearly in the front-rear direction from the rear portion to the front end portion, while the lower flange portion is In this configuration, the vehicle is positioned so as to gradually move outward in the vehicle width direction from the rear portion toward the front end portion.
[0009]
In the case of the above configuration, the rear part of the front side frame is formed in a vertically long cross-sectional shape, and the aspect ratio approaches 1 as the range from the rear part to the front end part advances toward the front end part, and the cross-sectional shape is square Will be closer. Here, when the cross-sectional shape is a square, the cross-sectional rigidity with respect to either the vertical axis or the vehicle width direction axis is equal, and the external force input to the left and right walls on both sides in the vehicle width direction is also Both of the external forces input to the upper and lower walls have the same proof strength. In addition, when the cross-sectional shape is a square, when an external force is input from the front, the external force is uniformly distributed as an axial force to the upper and lower walls and the left and right walls. For this reason, even if the action direction of the collision load is not forward but slightly changes in the action direction such as obliquely forward on the front end side of the front side frame, it is difficult to bend with respect to the collision load from the changed action direction. In addition, the collision load from the acting direction is received as an axial force, and the front end side of the front side frame is easily effectively compressed and deformed (buckled) by the axial force. On the other hand, since the rear side of the front side frame has a vertically long cross-sectional shape, even if a vertical external force from a suspension or the like is input, the external force can be effectively supported. Moreover, since the cross-sectional shape is not the same in the front-rear direction of the front side frame, but the cross-sectional shape is changed, as described above, there are conflicting requirements for the rigidity of the front side frame on the front end side and the rear end side. It is possible to satisfy the demand for weight reduction while achieving both.
[0010]
In the case of the above configuration, the front side frame as the front side frame is disposed at both the left and right positions of the front portion of the vehicle, and as each front side frame advances toward the front end portion, Since the lateral dimension is increased, the bending resistance is increased with respect to the collision load from an oblique front due to the offset collision, and it is possible to more effectively counter the variation in the acting direction of the collision load.
[0011]
According to a second aspect of the present invention, in the first aspect of the present invention, the front side frame is provided with an impact mitigation portion for mitigating an impact acting in the front-rear direction at the front side frame side position, and at the rear end side position at the vehicle width direction. It is set as the structure which provides the reinforcement part which resists bending to the side.
[0012]
In the above configuration, while preventing bending of the front end-side front side frame of the relative collision load to be input to the front end portion of the front side frame, of the vehicle body acting at the time of collision by the shock absorbing unit longitudinal direction of the impact energy And the transmission of the collision load to the passenger compartment side can be relaxed. In addition, since the reinforcing portion suppresses or prevents bending deformation in the vehicle width direction on the rear end side of the front side frame and suppresses or prevents bending based on the vertical external force input from the suspension or the like, It is possible to reliably receive the collision load as an axial force and cause buckling deformation on the front end side of the front side frame.
[0013]
Further, in the invention described in claim 3, as the impact mitigating part in the invention described in claim 2 , the concaves and convexes inward and outward in the cross-sectional direction are alternately repeated in the front-rear direction with respect to the wall surface part constituting the front side frame. It is comprised by the bellows bead formed in this way.
[0014]
In the case of the above configuration, the bellows bead is reliably compressed and deformed (collapsed) in the front-rear direction with respect to the axial load input to the front end portion side of the front side frame, and collision energy can be reliably absorbed.
[0015]
Furthermore, the invention according to claim 4 comprises the reinforcing portion according to the invention according to claim 2 by a gusset plate attached along a bent portion that bends downward from the rear end side of the front side frame toward the passenger compartment. To do.
[0016]
In the case of the above configuration, the rear end portion of the front side frame is reliably reinforced by the gusset plate.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a plan view of a front body structure of a vehicle according to an embodiment of the present invention. In the figure, reference numerals 1 and 1 denote a pair of front side frames disposed at both left and right (vehicle width direction) positions of the vehicle so as to extend in the front-rear direction, and 2 and 2 are attached to the front end of each front side frame 1. The crash box 3 is a front cross member extending in the left-right direction so as to connect the front end portions of the front side frames 1, and 4 is a shroud upper 5 extending in the left-right direction substantially above the front cross member 3. It is a dash panel that is mounted across the two front side frames 1 and 1.
[0019]
A space between the front side frames 1 and 1 in front of the dash panel 5 is an engine room 6 in which an engine or the like is disposed, and a rear space of the dash panel 5 is a vehicle compartment 7. . 8 and 8 are front wheel tire houses, and 9 and 9 are suspension towers for supporting the front wheels. A suspension cross member, which will be described later, for supporting the suspension is supported on the rear end side of each front side frame 1. Has been. Further, a torque box 11 as a reinforcing member is spanned between the position of each front side frame 1 on the side of the passenger compartment 7 and the side sill 10, and the torque box 11 allows the front side frame 1 and the side sill 10 to be connected to each other. Are connected to each other. Each torque box 11 is formed of a panel material in a cylindrical shape having a closed cross section, and its outer end is fixed so as to cover the upper surface of the side sill 10. As a result, the strength of resistance against the swing of each front side frame 1 around the vehicle width direction axis is increased. In FIG. 1, 12 is a tunnel and 13 is a bumper.
[0020]
Each of the front side frames 1 is configured as a so-called double hat type as shown in FIGS. 2 to 4, and a pair of panel members 15, 16 whose sections are press-molded in a hat shape face each other. The two upper flange portions 15a, 16a and the lower flange portions 15b, 16b are joined to each other by welding to form a rectangular closed cross-sectional shape. Each of the front side frames 1 has a vertical dimension in the vehicle width direction at the rear part from the rear end 17 side (the right end side in FIG. 2), which is the side supporting the suspension 9a, to the middle position in the front-rear direction. It has a vertically long rectangular cross-sectional shape that is longer than the horizontal dimension, and has a cross-sectional shape that is closer to a square as it goes to the front end 18 side (left end side in FIG. 2). That is, in each of the front side frames 1, the cross-sectional shape is changed and set so that the aspect ratio, which is the ratio of the vertical dimension to the horizontal dimension, approaches 1 as it advances toward the front end 18.
[0021]
More specifically, at the position on the front side of the rear portion (see FIG. 4), the horizontal dimension W is set to “3” and the vertical dimension H is set to “6”, and the aspect ratio is set to 2. On the other hand, at the position on the front end 18 side (see FIG. 3), the ratio of the horizontal dimension W to “5” and the vertical dimension H to “6” is set to 1.2, and the aspect ratio is set to 1.2. The aspect ratio is made to approach 1 as it progresses.
[0022]
In addition, each of the front side frames 1 maintains the vertical dimension H in the range from the rear part to the front end part 18, and the lateral dimension increases in the vehicle width as it advances from the rear part to the front end part 18 side. As a result, each front side frame 1 is formed to bulge outward in the vehicle width direction as it advances toward the front end 18.
[0023]
By changing the cross-sectional shape as described above, the rear end portion 17 side increases the resistance strength against the swing around the vehicle width direction axis against the input load from the suspension 9a, while the front end side Even when a collision load from an oblique front is input, bending in the vehicle width direction is difficult to occur, and the collision load is easily absorbed due to a crushing deformation (buckling deformation) in the front-rear direction. In addition, the optimum cross-sectional shape according to each part in the front-rear direction results in a reduction in weight.
[0024]
Moreover, the vehicle width direction position of said upper-and-lower flange part 15a, 16a, 15b, 16b is changed with respect to the front-back direction. That is, the upper flange portions 15a and 16a are positioned so as to extend straight from the front side of the rear portion to the front end portion 18 along the side surface of the inner panel member 15, while the lower flange portions 15b and 16b are positioned on the rear portion. The vehicle is positioned so as to gradually move outward in the vehicle width direction as the lateral dimension increases. Thereby, the gravity center position in each cross section of each front side frame 1 is changed with the change of the cross section shape.
[0025]
On the other hand, the rear end portion 17 of each of the front side frames 1 is bent slightly upward from the lower position of the vehicle compartment 7 from the vehicle compartment 7 side to the engine compartment 6 side with the dash panel 5 interposed therebetween as shown in FIG. The gusset plate 20 is joined from below so as to cover the lower surface of the bent portion 19 and the left and right side surfaces continuous from the lower surface. A suspension cross member (subframe) 9b for supporting the suspension 9a is attached to the gusset plate 20 at fixing portions 9c and 9c, and the vertical external force input from the suspension 9a is applied by the attachment portion of the gusset plate 20. It has come to be supported. As a result, the resistance of the rear end portion 17 of each front side frame 1 with respect to rocking around the vehicle width direction axis based on the external force in the vertical direction is further increased, and the vehicle width direction based on the vertically long cross-sectional shape is increased. Reinforcement against a decrease in bending strength is achieved. In FIG. 5, reference numeral 4 a denotes a radiator held by the shroud upper 4.
[0026]
Further, as shown in FIGS. 5 to 7, the both side walls in the predetermined front-rear direction range on the front end 18 side of each front side frame 1 are arranged in the front-rear direction so as to be uneven in the vehicle width direction. When the first beads 21, 21 bent alternately and repeatedly are formed, and the first beads 21, 21 are heavy collision loads such that the collision load from the front reaches each front side frame 1, Each front side frame 1 is reliably crushed and deformed in the front-rear direction to absorb the heavy collision load. The first beads 21 and 21 are bent at the wall portions of the panel members 15 and 16 on both the inner and outer sides so as to have an uneven shape in the same direction with respect to the vehicle width direction. In the case of the accordion type bent in the direction, the possibility that the upper and lower flange portions will be opened is avoided, and uniform crushing deformation is surely generated in the front-rear direction. Further, 15c, 16c,... In FIG. 5 are V-shaped bent portions formed on the lower flange portions 15b, 16b corresponding to the unevenness of the first bead 21.
[0027]
Further, a second bead 22 is formed at the front end position of the first bead 21, 21, and continues to the entire circumference of the rectangular cross section of each front side frame 1. A collision load acts from the front by the second bead 22. In this case, first, the second bead 22 is compressed and crushed so that each front side frame 1 is surely crushed in the front-rear direction.
[0028]
The first bead 21 and the second bead 22 constitute an accordion bead, and each front side frame 1 is reliably compressed in the front-rear direction by a collision load input from the front by the accordion bead. Collision energy is absorbed by causing the crushing deformation.
[0029]
In addition, the crash box 2 fixed to the front end of the front end portion 18 of each front side frame 1 is formed into a substantially bowl shape by press molding using a plate material, and the collision load from the front is a light collision load. In this case, the collision energy is absorbed by causing crushing deformation so that each front side frame 1 is not affected. Even when the collision load is a heavy collision load, initial absorption of collision energy is performed before the collision load acts on each front side frame 1.
[0030]
<Other embodiments>
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. That is, in the above-described embodiment, the first and second beads 21 and 22 are configured as the bellows beads. However, the present invention is not limited thereto, and may be configured by any one of the first and second beads 21 and 22. Further, the bellows bead may be constituted by a slot-like notch.
[0031]
【The invention's effect】
As described above, according to the vehicle front body structure in the first aspect of the invention, on the front end side of the front side frame, the action direction of the collision load is not forward but diagonally forward due to offset collision or the like. even if some variation in the direction, while it is possible to easily by effectively compressing deformation of the front end portion of the front side frame (buckling) to the collision load from the fluctuation of action direction, of the front side frame On the rear end side, even if a vertical external force from the suspension or the like is input, the external force can be effectively supported. In addition, it is possible to satisfy the requirement for weight reduction while satisfying the conflicting requirements for the rigidity of the front end portion side and the rear end portion side of the front side frame.
[0032]
Further , according to the first aspect of the present invention, it is possible to more effectively counter the collision load from obliquely forward due to the offset collision.
[0033]
According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the reinforcing portion suppresses or prevents the bending deformation or bending of the rear end portion side of the front side frame, thereby reliably colliding the collision load. It can be input to the front side frame as a directional force, which can surely cause buckling deformation of the front side frame. In addition, the buckling deformation in the axial direction of the front side frame can be caused more reliably in combination with the impact mitigating portion, and the collision energy can be more reliably absorbed.
[0034]
Further, according to the invention described in claim 3, it is possible to specifically identify the impact mitigating portion in the invention according to claim 2, and input to the front end portion side of the front side frame by the bellows bead as the impact mitigating portion. The front side frame is reliably compressed and deformed (collapsed) in the front-rear direction with respect to the axial load to be applied, so that collision energy can be reliably absorbed.
[0035]
Furthermore, according to the invention described in claim 4 , the reinforcing portion in the invention described in claim 2 can be specifically specified, and the rear end portion side of the front side frame is reinforced by the gusset plate as the reinforcing portion. Surely done.
[Brief description of the drawings]
FIG. 1 is an explanatory plan view of a vehicle body structure at a front portion of a vehicle according to an embodiment.
FIG. 2 is an enlarged plan view of the front side frame of FIG. 1;
FIG. 3 is an end surface explanatory view taken along line AA in FIG. 2;
4 is an end surface explanatory view taken along line BB in FIG. 2; FIG.
FIG. 5 is a partially omitted enlarged arrow view taken along the line CC in FIG. 1;
FIG. 6 is a partial perspective view of the front side frame on the front end side.
7 is a partially omitted enlarged cross-sectional explanatory view taken along the line DD in FIG. 5. FIG.
[Explanation of symbols]
1 Front Side Frame 17 Front Side Frame Rear End 18 Front Side Frame Front End 20 Gusset Plate (Reinforcement)
21 1st bead (accordion bead; impact mitigation part)
22 2nd bead (bellows bead; impact mitigation part)
H Vertical dimension W Horizontal dimension

Claims (4)

In the front body structure of a vehicle provided with a pair of front side frames extending in the front-rear direction , disposed at both left and right positions in the front portion of the vehicle,
Each of the front side frames has an aspect ratio, which is a ratio of the vertical dimension in the vertical direction to the horizontal dimension in the vehicle width direction, from the rear part to the front end part in which the vertical dimension is set to a vertically long cross-sectional shape that is longer than the horizontal dimension. It has a cross-sectional shape that is changed so as to approach 1 as it goes to the side. From the rear part to the front end part, it keeps the vertical dimension substantially constant, while moving the horizontal dimension to the front end side, the vehicle width direction It is formed to increase more with respect to the outside, and has an upper flange part and a lower flange part,
The upper flange portion is positioned so as to extend linearly in the front-rear direction from the rear portion to the front end portion, while the lower flange portion gradually moves in the vehicle width direction as it advances from the rear portion to the front end portion. A vehicle front body structure characterized by being positioned to move outward . In claim 1 ,
The front side frame is provided with an impact mitigation part that mitigates the impact acting in the front-rear direction on the front end side position, while the rear end side position is provided with a reinforcement part that resists bending in the vehicle width direction. The vehicle body structure of the front part of the vehicle characterized by the above-mentioned. In claim 2 ,
The impact mitigating portion is configured by a bellows bead formed so that unevenness inward and outward in the cross-sectional direction is alternately repeated in the front-rear direction with respect to the wall surface portion constituting the front side frame. Front body structure of the vehicle. In claim 2 ,
The vehicle front body structure characterized in that the reinforcing portion is constituted by a gusset plate attached along a bent portion that is bent downward from the rear end portion side of the front side frame to the vehicle compartment side.

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