JPH1120737A - Front body structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish both of reduction in weight and fulfillment of demands for the front end part side of a front frame in case of a collision and for the rear end part side of the front frame for supporting a suspension and the like. SOLUTION: In the front part of a vehicle, lateral cross sectional shapes of a pair of front side frames 1, 1 are varied in the longitudinal direction. Each front side frame 1 is formed so as to be provided with a double hat type rectangular cross section. On the rear end part, 17 side of each front side frame 1, a rear part, supporting a suspension 9 is formed so as to be provided with a rectangular cross section, in which a vertical dimension is longer than a lateral dimension in the vehicle width direction, and toward the front end part, 18 side, the lateral dimension is increased toward the outside in the vehicle width direction while the vertical dimension is kept constant, so that the cross section shape is brought close to a square. On the front end part 18 side of each front side frame 1, a bellows bead causing crush deformation in the longitudinal direction is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front body structure of a vehicle having a front frame.

[0002]

2. Description of the Related Art Heretofore, as a front body structure of a vehicle of this kind, there has been known a structure in which a front frame is constituted by a so-called double-hat type frame (for example, see Japanese Patent Application Laid-Open No. 7-70093). In this device, a pair of panels each having a hat-shaped cross section face each other and their respective flanges are joined to each other, thereby forming a front frame having a rectangular cross section. In addition, in this device, a bellows bead is formed which alternately repeats irregularities in a predetermined front-rear direction range on the front end side of the front frame, so that a collision load input from the front of the vehicle in the axial direction (front-rear direction) of the front frame is reduced. On the other hand, a predetermined crushing deformation is caused.

Further, the front frame used for the front body structure of the vehicle needs to support the engine and the suspension and to resist a collision load from the front. It is common practice to use a frame having a rectangular cross section (see, for example, US Pat. No. 3,912,295).
Furthermore, when the front frame is formed in a rectangular shape using a hat-shaped panel, the rectangular cross-sectional shape has the same size and shape over substantially the 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 (for example, see US Pat. No. 4,133,549).

[0004]

The front body of the vehicle is subjected to a frontal collision load due to a head-on collision, a diagonal front-side collision load due to a so-called offset collision, or a side-to-side collision load. There is a possibility that a collision load from various directions such as is applied. For this reason, when the front body is constituted by a front frame, it is necessary to take measures against the above-mentioned collision loads from various directions.

[0005] However, the above-mentioned front frame is required to have conflicting rigidity in each of the front-rear portions. For example, since it is necessary to support the suspension on the rear end side of the front frame, it is necessary to suppress swinging around the vehicle width direction axis against a vertical external force input from the suspension or the like. There is. Therefore, it is necessary to increase the sectional rigidity with respect to the vehicle width direction axis on the rear end side of the front frame. On the other hand, on the front end side of the front frame, it is necessary to be able to withstand collision loads from various directions as described above. Further, at this time, although the front frame can be compressed in the front-rear direction to absorb the collision energy by providing the bellows bead as described above, the collision load from the oblique front due to the offset collision is received. If the front end of the front frame is bent and deformed in the vehicle width direction, a situation may occur in which the collision energy cannot be absorbed by the compression in the front-rear direction. In addition, it is necessary to suppress bending in the vehicle width direction even for a collision load from the side. Therefore, in order to prevent bending deformation in the vehicle width direction, it is necessary to increase the sectional rigidity with respect to the vertical axis on the front end side of the front frame.

On the other hand, if the cross-sectional area or the like is increased in order to increase the cross-sectional rigidity of the front frame, the weight of the vehicle is increased, which contradicts the demand for weight reduction.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the weight while reducing the demands on the front end side of the front frame at the time of collision and the suspension and the like. The object of the present invention is to satisfy both the requirements for the rear end portion of the front frame for supporting.

[0008]

In order to achieve the above object, the invention according to claim 1 is based on a front body structure of a vehicle having a front frame extending in a front-rear direction at a front portion of the vehicle. The cross-sectional shape of the front frame is changed in the front-rear direction. That is, the aspect ratio, which is the ratio of the vertical dimension in the vertical direction to the horizontal dimension in the vehicle width direction, is increased by 1 from the rear portion to the front end side where the vertical dimension is set to a vertically long cross-sectional shape longer than the horizontal dimension.
Is changed and set so as to approach.

In the above configuration, the rear portion of the front frame is formed in a vertically long cross-sectional shape, and the aspect ratio becomes 1 as the range from the rear portion to the front end advances toward the front end.
And the cross-sectional shape becomes closer to a square. Here, if the cross-sectional shape is a square, the cross-sectional rigidity with respect to any of the vertical axis and the vehicle width direction axis becomes equal, and even for external forces input to the left and right walls on both sides in the vehicle width direction,
The same proof stress is applied to external forces input to the upper and lower walls on both sides in the vertical direction. 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 to the upper and lower walls and the left and right walls as axial forces. For this reason, even if the action direction of the collision load on the front end side of the front frame slightly changes not in the forward direction but in the oblique front direction or the like, it is difficult to bend against 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 axial force facilitates effective compression deformation (buckling deformation) of the front end portion of the front frame.
On the other hand, the rear end portion of the front frame has a vertically long cross-sectional shape, so that even if a vertical external force from a suspension or the like is input, the external force can be effectively supported. In addition, since the front frame has a variable cross-section instead of the same cross-sectional shape in the front-rear direction, the conflicting requirements for the rigidity of the front frame between the front end side and the rear end side are satisfied as described above. At the same time, it is possible to satisfy the demand for weight reduction.

According to a second aspect of the present invention, in the first aspect of the invention, the lateral dimension is increased from the rear portion to the front end portion while keeping the vertical dimension substantially constant while increasing the lateral dimension toward the front end portion. Is what you do.

In the above configuration, the change in the cross-sectional shape of the front frame with respect to the front-rear direction is realized by changing the horizontal dimension while making the vertical dimension substantially the same. Thus, compatibility with the requirements on the rear end side can be realized while further reducing the weight.

According to a third aspect of the present invention, the front frame according to the first aspect of the present invention includes a pair of front side frames disposed at both left and right positions at the front of the vehicle. The above-mentioned front side frames are formed so as to keep the vertical dimension substantially constant from the rear part to the front end part, and to increase the lateral dimension further outward in the vehicle width direction as the lateral dimension moves toward the front end part. It is.

In the above configuration, the front side frames as the front frames are respectively disposed at the left and right sides of the front portion of the vehicle, and the front side frames move outward in the vehicle width direction as the front side frames move toward the front end. Since the lateral dimension is increased on the side, the bending resistance is increased with respect to a collision load from an oblique front due to an offset collision, and it becomes possible to more effectively counter the fluctuation in the direction of action of the collision load.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a shock absorbing portion for reducing an impact acting on the front end portion of the front frame in the front-rear direction is provided. On the other hand, a reinforcing portion that resists bending in the vehicle width direction is provided at the rear end side position.

[0015] In the case of the above structure, the impact load applied to the front end portion of the front frame prevents the front frame at the front end portion from being bent, and the impact absorbing portion acts on the front-rear impact of the vehicle body at the time of the collision. Energy can be absorbed to reduce the transmission of the collision load to the cabin. On top of that, the reinforcing portion suppresses or prevents bending deformation in the vehicle width direction on the rear end side of the front frame and suppresses or prevents bending based on external vertical force input from a 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 frame.

According to a fifth aspect of the present invention, in the invention of the fourth aspect, as the shock absorbing portion, irregularities inward and outward in a cross-sectional direction are alternately formed in a front-rear direction with respect to a wall portion constituting the front frame. The bellows beads are formed so as to be repeated.

In the case of the above configuration, the bellows bead is reliably compressed and deformed (crushed) in the front-rear direction with respect to the axial load applied to the front end side of the front frame, so that the collision energy can be reliably absorbed.

Further, the invention according to claim 6 is the invention according to claim 4.
The reinforcing portion according to the invention described above is constituted by a gusset plate attached along a bent portion bent downward from the rear end side of the front frame to the vehicle compartment side.

In the case of the above construction, the rear end of the front frame is reliably reinforced by the gusset plate.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a front body structure of a vehicle according to an embodiment of the present invention. In FIG. 1, reference numerals 1 and 1 denote a pair of front side frames as front frames disposed so as to extend in the front-rear direction at left and right sides (vehicle width direction) of the vehicle. Crash box attached to front end, 3
Is a front cross member extending in the left-right direction so as to connect both front ends of the front side frames 1, 4 is a shroud upper extending in a left-right direction substantially above the front cross member 3, and 5 is both front side frames. It is a dash panel attached across 1,1.

A space in front of the dash panel 5 and between the front side frames 1 and 1 is an engine room 6 in which an engine and the like are disposed, and a space behind the dash panel 5 is a vehicle room 7. It is said. Also, 8,8
Is a tire house for the front wheels, and 9 and 9 are suspension towers for supporting the front wheels. Suspension cross members (described later) for supporting the suspensions are supported on the rear end sides of the front side frames 1. Further, the cabin 7 of each of the above front side frames 1
A torque box 11 as a reinforcing member is bridged between the side position and the side sill 10, and the front side frames 1 and the side sills 10 are connected to each other by the torque box 11. Each of the torque boxes 11 is formed of a panel material into a cylindrical shape having a closed cross section, and the outer end thereof is fixed so as to cover the upper surface of the side sill 10. Thereby, the resistance strength against the swing of each of the front side frames 1 around the vehicle width direction axis is enhanced. In FIG. 1, 12 is a tunnel, and 13 is a bumper.

Each of the front side frames 1 is shown in FIG.
As shown in FIG. 4, the upper flange portion 15 a is formed in a so-called double hat type, and a pair of panel members 15, 16 each having a cross-section press-formed in a hat shape face each other and face each other. , 16a and the lower flange portions 15b, 16b are welded to each other to form a rectangular closed cross-sectional shape. In each of the front side frames 1, the rear portion from the rear end 17 side (the right end side in FIG. 2), which is the side supporting the suspension 9a, to the intermediate position in the front-rear direction has the vertical dimension in the up-down direction set in the vehicle width direction. Are formed so as to have a vertically long rectangular cross-sectional shape longer than the horizontal dimension and have a cross-sectional shape closer to a square as it goes to the front end portion 18 side (the left end portion side in FIG. 2). That is, each of the front side frames 1
In this example, 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.

More specifically, at the front position (see FIG. 4) of the rear portion (see FIG. 4), the horizontal dimension W is set to 3 and the vertical dimension H is set to 6 so that the aspect ratio is reduced. On the other hand, at the position on the front end 18 side (see FIG. 3), the horizontal dimension W is set to the ratio of “5” to the vertical dimension H, and the aspect ratio is set to 1.2. The aspect ratio approaches 1 as it proceeds to the 18 side.

In addition, each of the front side frames 1
In the range from the rear portion to the front end portion 18, while keeping the vertical dimension H substantially the same, the lateral dimension increases outward in the vehicle width direction from the rear portion to the front end portion 18 (FIG. 2).
As a result, each front side frame 1 is formed so as to bulge outward in the vehicle width direction as it advances toward the front end portion 18.

By changing the cross-sectional shape as described above, the rear end 1
On the side 7, the resistance to swinging around the vehicle width direction is increased against the input load from the suspension 9 a, while the front end side of the vehicle is not affected by a collision load from the front or obliquely front of the vehicle. Bending in the width direction is unlikely to occur, and the collision load is easily absorbed by crushing deformation (buckling deformation) in the front-rear direction. Moreover, by making the cross-sectional shape optimal for each part in the front-back direction, the weight can be reduced as a result.

The upper and lower flange portions 15a, 16
The positions of a, 15b, and 16b in the vehicle width direction are changed in the front-rear direction. That is, the upper flange portions 15a, 16a
Are positioned so as to extend straight from the front side of the rear portion along the side surface of the inner panel member 15 to the front end portion 18, while the lower flange portions 15 b and 16 b follow the increase in the lateral dimension from the rear portion. It is positioned so as to gradually move outward in the vehicle width direction. Thereby, the position of the center of gravity in each cross section of each front side frame 1 is changed according to the change of the cross section shape.

On the other hand, as shown in FIG. 5, the rear end 17 of each of the front side frames 1 has a vehicle compartment 7 from the vehicle compartment 7 side to the engine room 6 side with the dash panel 5 interposed therebetween.
A gusset plate 20 is joined from below so as to bend slightly upward from a lower position of the bent portion 19 and 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 (sub-frame) for supporting the suspension 9a is provided on the gusset plate 20.
Reference numeral 9b is attached to the fixing portions 9c, 9c, and the mounting portion of the gusset plate 20 supports the vertical external force input from the suspension 9a. As a result, the rear end portion 17 of each of the front side frames 1 further increases the resistance strength against swinging around the vehicle width direction axis based on the vertical external force, and the vehicle width direction based on the vertically long cross-sectional shape. Reinforcement for reduction in bending strength is achieved. In FIG. 5, reference numeral 4a denotes a radiator held by the shroud upper 4.

As shown in FIGS. 5 to 7, the front side frames 1 are formed with irregularities on both side walls of the front end portion 18 on the front end portion 18 side in a predetermined longitudinal direction. The first folded alternately in the front and rear direction
Beads 21 and 21 are formed, and the first beads 21 and 21 are formed.
In the case of a heavy collision load such that the collision load from the front reaches each front side frame 1 due to 1, each of the front side frames 1 is reliably crushed and deformed in the front-rear direction to absorb the heavy collision load. Is being done. In addition, 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 uneven shapes in the same direction with respect to the vehicle width direction.
In order to avoid the possibility that the upper and lower flange parts will be opened when the accordion type is bent in the opposite direction on both side walls, it is ensured that uniform crushing deformation occurs in the front and rear direction I have. Also, 15c in FIG.
Reference numerals 16c,... Are V-shaped bent portions formed on the lower flange portions 15b, 16b corresponding to the irregularities of the first bead 21.

Further, a second bead 22 is formed at the front end of each of the first beads 21 and 21 so as to be continuous with the entire periphery of the rectangular cross section of each front side frame 1.
When a collision load acts on the bead 22 from the front,
First, when the second bead 22 is compressed and crushed, a trigger is provided so that each front side frame 1 is reliably crushed in the front-rear direction.

The first bead 21 and the second bead 22
A bellows bead is formed by the bellows, and the front side frame 1 is reliably compressed in the front-rear direction by a collision load input from the front by the bellows bead, causing a buckling-like crushing deformation to absorb the collision energy. Can be

In addition, each of the front side frames 1
Box 2 fixed to the front end of front end 18
Is formed into a substantially bowl shape by press molding using a plate material, and when the collision load from the front is a light collision load, it crushes and deforms to absorb the collision energy, and is applied to each front side frame 1. It has no effect. Even when the collision load is a heavy collision load, the initial absorption of the collision energy is performed before the collision load acts on each front side frame 1.

<Other Embodiments> The present invention is not limited to the above embodiments, but includes various other embodiments. That is, in the above embodiment,
The bellows bead is constituted by the first and second beads 21 and 22, but is not limited to this, and the first and second beads 2
Alternatively, the bellows bead may be formed by a slot-shaped notch.

[0034]

As described above, according to the front body structure of the vehicle according to the first aspect of the present invention, the direction of impact of the collision load is not forward but obliquely forward due to offset collision at the front end side of the front frame. Therefore, even if the action direction slightly changes, the front end side of the front frame can be easily subjected to effective compression deformation (buckling deformation) in response to a collision load from the changed action direction. On the rear end side of the frame, even if a vertical external force from a suspension or the like is input, the external force can be effectively supported. In addition, it is possible to satisfy the demands for weight reduction while satisfying the conflicting requirements for the rigidity of the front end side and the rear end side of the front frame.

According to the second aspect of the invention, in addition to the effect of the first aspect, the requirement of the rigidity of the front frame at the front end side and the requirement at the rear end side can be both satisfied. It can be realized while reducing the weight.

According to the third aspect of the present invention, in addition to the effect of the first aspect of the present invention, it is possible to more effectively counter a collision load from an oblique front due to an offset collision.

According to the invention set forth in claim 4, claims 1 to
In addition to the effect of the invention according to any one of claims 3 to 11, the reinforcing frame suppresses or prevents bending deformation and bending on the rear end side of the front frame, thereby reliably reducing the collision load as an axial force. , So that the buckling deformation of the front frame can be reliably caused. In addition, the buckling deformation of the front frame in the axial direction can be more reliably generated in cooperation with the shock absorbing portion, and the collision energy can be more reliably absorbed.

According to the fifth aspect of the present invention, it is possible to specifically specify the shock absorbing portion according to the fourth aspect of the present invention. Thus, the front frame can be reliably compressed and deformed (crushed) in the front-rear direction with respect to the axial load input to the vehicle, so that the collision energy can be reliably absorbed.

Further, according to the sixth aspect of the present invention, the reinforcing portion in the fourth aspect of the invention can be specifically specified, and the gusset plate as the reinforcing portion allows the rear end portion of the front frame to be specified. Reinforcement is ensured.

[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 explanatory end view taken along line AA of FIG. 2;

FIG. 4 is an explanatory end view taken along line BB in FIG. 2;

FIG. 5 is a partially omitted enlarged view taken on line CC of FIG. 1;

FIG. 6 is a partial perspective view of a front end side of a front side frame.

FIG. 7 is an enlarged sectional explanatory view taken along a line DD of FIG. 5;

[Description of Signs] 1 Front side frame (front frame) 17 Rear end of front frame 18 Front end of front frame 20 Gusset plate (reinforcing part) 21 First bead (bellows bead; shock absorbing part) 22 Second bead ( Bellows bead; shock absorbing part) H vertical dimension W horizontal dimension

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ichiro Kamimoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (6)

[Claims] 1. A front body structure of a vehicle having a front frame extending in a front-rear direction at a front portion of the vehicle, wherein the front frame has an aspect ratio which is a ratio of a vertical dimension in a vertical direction to a horizontal dimension in a vehicle width direction. Has a cross-sectional shape that is changed and set to approach 1 as it progresses from a rear portion set to a vertically long cross-sectional shape in which the vertical dimension is longer than the horizontal dimension toward the front end side. Body structure of the vehicle to be driven. 2. The vehicle according to claim 1, wherein the width is increased from the rear portion to the front end portion while keeping the vertical size substantially constant while increasing the horizontal size toward the front end portion. Front body structure. 3. The front frame according to claim 1, further comprising a pair of front side frames disposed at left and right sides of a front portion of the vehicle as the front frame, wherein each of the front side frames extends vertically from a rear portion to a front end portion. A front body structure of a vehicle, characterized in that the width is increased outwardly in the vehicle width direction as the lateral dimension advances toward the front end while the dimension is kept substantially constant. 4. The front end of the front frame according to any one of claims 1 to 3, wherein the front end of the front frame is provided with a shock absorbing portion for reducing an impact acting in the front-rear direction. A front body structure of a vehicle, wherein a reinforcing portion that resists bending in a vehicle width direction is provided at a side position. 5. The shock absorbing portion according to claim 4, wherein the shock absorbing portion is formed by a bellows bead formed in such a manner that irregularities inward and outward in a cross-sectional direction are alternately repeated in a front-rear direction with respect to a wall portion constituting the front frame. A front vehicle body structure for a vehicle, comprising: 6. The gusset plate according to claim 4, wherein the reinforcing portion is formed by a gusset plate attached along a bent portion bent downward from a rear end side of the front frame to a vehicle compartment side. Vehicle front body structure.