JP2003306171A - Front side member structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively deform a bent portion at the border between a member body and an inclined portion of a front side member and restrain action of a load on a dash panel by deforming longitudinal walls of the bent portion outward of the sections and reducing the sectional secondary moment when inputting the load. <P>SOLUTION: A fragile portion 20 is formed at the bent portion 1B where the front side member 1 with a closed section structure bends downward along an inclination of the dash panel 10 for permitting expansible deformation outward of sections of the longitudinal walls 3b, 3c of the bent portion 1B. A deformation inducing means 30 is provided in front of the bent portion 1B for inducing expansible deformation of the longitudinal walls 3b, 3c for the input load from the front part and reducing the sectional secondary moment. The bent portion 1B is positively deformed for increasing absorbing efficiency of the input energy. A deformation restraining means 40 is provided at the inclined portion 1C along the inclination of the dash panel 10 for preventing a cabin deformation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front side member structure which is disposed on both sides of a front compartment of an automobile in a vehicle width direction so as to extend in the vehicle front-rear direction.

[0002]

2. Description of the Related Art A front side member of a vehicle is arranged on both sides of a front compartment in the vehicle width direction so as to extend in the vehicle front-rear direction, forms a closed cross section to form a main skeleton of the front part of a vehicle, and also serves as a shaft for a frontal collision. It has a function as a main energy absorbing member that crushes in the direction and absorbs collision energy.

The front side member is extended from the rear portion of the front side main body of the front member to an inclined portion which is bent downward along the inclined surface of the toe board of the dash panel and then extends around the lower surface of the floor to form an extension portion. Due to this configuration, when the load from the front of the vehicle is input to the front side member in the axial direction, if the inclined part along the inclined surface of the dash panel deforms, the amount of backward deformation of the dash panel increases. There is a possibility that

Therefore, in order to prevent the dash panel from retracting when a load is applied from the front, it is conceivable to reinforce the rear part of the front side member. For example, Japanese Patent Laid-Open No. 9-95260 discloses a front side member. There is disclosed a structure in which a member (reinforcement member) that connects upper surfaces of members in a region from a rear portion of a member main body to an inclined portion is connected with a smooth curved surface.

[0005]

However, in such a reinforcing structure, the deformation of the entire rear portion of the front side member is suppressed, so that the axial crush deformation amount of the front side member in front of the dash panel is reduced. However, if a collision load is input, the amount of backward deformation of the dash panel toward the cabin side may be rather large.Therefore, it may be necessary to reinforce the cabin, resulting in an increase in vehicle weight and an increase in vehicle price. You will be forced to do so.

On the other hand, as an opposite idea for suppressing the deformation of the cabin, it is considered that the front side member is easily deformed, and the structure of the front side member in this case is disclosed in, for example, Japanese Patent Laid-Open No. 10-45023. It is possible to apply the energy absorbing member in which the plate thickness of the outer wall corner portion of the disclosed closed cross-section member having a rectangular cross section is formed thin.

However, when the outer wall corner portion is simply thinned to form the front side member in this way,
In a portion that receives a bending input, such as an inclined portion that is inclined downward along the inclined surface of the dash panel, the strain direction of the cross section that is deformed when a collision load is input cannot be specified. When the left and right vertical walls of the section are deformed inward in the cross section and the upper and lower walls are deformed outward in the section, the second moment of area of the inclined section in the deformation direction becomes large.

Therefore, the deformation of the rear portion of the front side member is suppressed, and even in this case, there is a possibility that the amount of backward deformation of the dash panel may be increased and the cabin must be reinforced again. become.

Therefore, according to the present invention, when a load is input, the vertical wall of the bent portion at the boundary between the member main body of the front side member and the inclined portion is deformed outward in the cross section to reduce the second moment of area, thereby making the bent portion. The present invention provides a front side member structure capable of suppressing the load from acting on the dash panel by positively deforming the.

[0010]

According to the invention of claim 1, the front compartments are arranged to extend in the vehicle front-rear direction on both sides of the front compartment in the vehicle width direction, and the rear portion is provided with an inclined portion along the inclined surface of the dash panel. In a front side member structure having a closed cross-section structure in which an extension part is formed around the lower surface of the floor via the, a vertical part of the bent part is formed at the bent part at the boundary between the front side member body and the inclined part of the front side member. While forming a fragile portion that promotes bulging deformation of the wall outward in cross section, a deformation inducing means that induces bulging deformation of the vertical wall with respect to an axial input load is provided in front of the bent portion, and It is characterized in that the deformation suppressing means is provided from the inclined portion to the extension portion.

According to a second aspect of the present invention, in the front side member structure according to the first aspect, the front side member includes a lower member formed in a U-shaped cross section by casting a light alloy, and the lower member. It is characterized in that a closed cross section is formed by an upper member formed of a light alloy plate material that is joined to cover the upper open portion of the side member.

According to a third aspect of the present invention, in the front side member structure according to the second aspect, the lower member and the upper member are welded and joined at least at the bent portion, and the welded portion is fragile. The feature is that it is a part of the section.

According to the invention of claim 4, claims 2 and 3 are provided.
In the front side member structure according to, the wall thickness of the ridge line portion of the boundary between the lower wall and the vertical wall of the front side member having the closed cross section is thinned at least in the bent portion,
The thin ridge line portion is characterized as a weak portion.

According to the invention of claim 5, claims 2 to 4 are provided.
In the front side member structure described in (1), the deformation inducing means is formed in a front portion of the bent portion so as to be integrally formed with a lateral rib that traverses a closed cross section of the front side member, and at a substantially central portion in the transverse direction of the lateral rib. It is characterized in that it is constituted by a vertical rib which is connected to extend in the front of the vehicle body and transmits an axial input load to the lateral rib.

In the invention of claim 6, claims 2 to 5 are provided.
In the front side member structure described in (1), the deformation suppressing means is constituted by a plurality of ribs connecting between the facing vertical walls from the inclined portion to the extension portion.

In the invention of claim 7, claims 2 to 6 are provided.
In the front side member structure described in (1), the fragile portion includes an extension allowing portion formed at a position corresponding to at least the bent portion of the upper wall of the front side member.

According to an eighth aspect of the present invention, in the front side member structure according to the first aspect, the front side member body including at least the bent portion of the front side member is formed of a plate material, and the fragile member is formed. The portion is characterized in that a first reinforcing member for increasing the strength is provided on the lower wall of the bent portion as compared with the vertical wall.

According to a ninth aspect of the present invention, in the front side member structure according to the eighth aspect, the deformation inducing means is formed with curved portions projecting inward in cross section on the vertical walls facing each other in front of the bent portion. A second reinforcing member having a shape along the curved portion is provided, and the second reinforcing member is formed by straddling the curved portion and connected to the front and rear of the curved portion.

According to the invention of claim 10, claim 8 and
The front side member structure described in Item 9 is characterized in that the deformation suppressing means is constituted by a third reinforcing member that is fitted and arranged along the inner peripheral surface of the inclined portion to the extension portion along the inner peripheral surface thereof.

[0020]

According to the invention described in claim 1, when a load from the front of the vehicle is input to the front side member, the vertical wall of the bent portion of the front side member is weakened by the deformation inducing means in front of the bent portion. Starting from the part, it bulges and deforms positively outward in the cross section.

Therefore, the bending portion is deformed in a cross section so as to be flat in the vertical bending deformation direction and the second moment of area is reduced, so that the bending portion can be easily deformed in the bending direction. The deformation suppressing unit can efficiently suppress the deformation of the inclined portion along the dash panel.

Therefore, the bent portion is deformed before the load input from the front acts on the dash panel, and the load energy can be effectively absorbed by the deformed bent portion. It is possible to effectively suppress the deformation of the dash panel and the deformation of the cabin without increasing the weight.

According to the invention of claim 2, claim 1
In addition to the effects of the present invention, since the front side member is composed of two members, a lower member made of a light alloy casting and an upper member made of a light alloy plate material, the number of parts is small and the assembly man-hour is reduced. It can be reduced.

According to the third and fourth aspects of the invention, in addition to the effect of the second aspect of the invention, the fragile portion can be easily formed and the bent portion can be surely deformed.

According to the invention of claim 5, claim 2
In addition to the effects of the inventions of to 4, the axial load input to the front end of the front side member can be satisfactorily transmitted as an outward deformation load of the vertical wall of the bent portion by the vertical rib and the horizontal rib, and the bending can be performed. The substantially flat cross-section deformation of the part can be induced more positively.

According to the invention of claim 6, claim 2
In addition to the effects of the inventions of to 5, the deformation suppressing means can be easily configured by the rib structure.

According to the invention of claim 7, claim 2
In addition to the effects of the inventions of to 6, since the upper wall of the bent portion is stretched and deformed by the fragile portion, the bending deformation of the bent portion in the vertical direction can be performed more smoothly.

According to the invention described in claim 8, claim 1
In addition to the effect of the invention described above, the increase in weight can be avoided by the plate material configuration of the front side member.

According to the invention of claim 9, claim 8
In addition to the effect of the invention described above, by forming the curved portion, the axial load can be satisfactorily transmitted to the vertical wall of the bent portion as an outward deformation load, and the substantially flat cross-section deformation of the bent portion is more actively induced. can do.

According to the tenth aspect of the invention, in addition to the effects of the eighth and ninth aspects of the invention, the deformation suppressing means can be easily constructed by the fitting arrangement of the third reinforcing member.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 7 show a first embodiment of a front side member structure according to the present invention, FIG. 1 is a side view showing a mounted state of the front side member, and FIG. 2 is an exploded perspective view of the front side member. 3 is an enlarged sectional view taken along line AA in FIG. 1, FIG. 4 is an enlarged sectional view taken along line BB in FIG. 1, and FIG. 5 is an enlarged sectional view taken along line CC in FIG. ,
6 is an enlarged sectional view taken along the line D-D in FIG. 1, and FIG. 7 is an enlarged sectional view corresponding to FIG. 4 showing a deformed state of the bent portion.

As shown in FIG. 1, the front side member 1 of the first embodiment is arranged to extend in the vehicle front-rear direction on both sides in the vehicle width direction of the front compartment, and has a substantially straight member body 1A on the front side. , Bent portion 1B at the rear
A closed cross-section structure including an inclined portion 1C that is inclined downward along the inclined surface of the toe board portion of the dash panel 10 and an extension portion 1D that wraps around the lower surface of the floor 11 following the inclined portion 1C. Is configured as.

The front side member 1 is roughly divided into a front member 2 forming a front portion and a lower member 3 and an upper member 4 forming a rear portion, which is divided into two portions in the front and rear at a member main body 1A. It

The front member 2 is formed by extrusion molding an aluminum alloy into a straight closed cross section having a rectangular cross section, and a bracket 2a for mounting a bumper reinforcement (not shown) is joined to the front end of the front member 2. When the collision load from the front is input, the colloid is crushed in the axial direction and can absorb the collision energy.

The lower member 3 is formed of a cast aluminum alloy as a light alloy in a U-shaped cross section, while the upper member 4 is also formed of a plate material of aluminum alloy. The upper cross-section is formed by connecting the upper member 4 so as to cover the upper open portion 3a of the upper part 3.

Bent portions 4a and 4b are formed on both sides of the upper member 4 so as to fit outside the vertical walls 3b and 3c of the lower member 3, respectively. As shown in FIGS. By welding W between the bent portions 4a and 4b and the vertical walls 3b and 3c in a state where the upper and lower portions of the vertical walls 3b and 3c of the lower member 3 are fitted to the lower member 3, The upper member 4 is integrated.

The front portion of the bent portion 4b located outward in the vehicle width direction is bent upward as shown in FIG. 2 to form an upper bent portion 4bf, and is also shown in FIGS. Thus, the vertical wall 3c on the outer side in the vehicle width direction is formed to be higher than the inner vertical wall 3b from the front end of the lower member 3 to the bent portion 1B.
The upper bent portion 4bf is fitted inside the tall vertical wall 3c and protrudes upward, and the protruding portion is spot-welded to the strut housing 12.

The strut housing 12 supports a strut (shock absorber) of a suspension (not shown), and the upper end of the strut housing 12 is connected to the hood ridge member 13 as shown in FIG.

Then, as shown in FIG. 6, the rear end of the front member 2 is inserted into the front ends of the lower member 3 and the upper member 4 welded to each other as a closed cross-section structure, and the bolt 1
4, the front side member 1 is configured by being fixed via nuts 14a, and the extension portion 1D at the rear end of the front side member 1 configured in this manner is used as shown in FIG. It is bent outward in the width direction and is directly coupled to the front end portions of the side sills 15 extending in the front-rear direction on the left and right sides of the floor 11.

When the rear end portion of the extension portion 1D is made straight, the rear end portion and the side sill 15 are formed.
An outrigger (not shown) intervenes in the vehicle width direction between the front end of the vehicle and the front end of the vehicle and is indirectly coupled via the outrigger.

Here, in the present embodiment, the vertical walls 3b, 3 of the bent portion 1B are formed on the bent portion 1B of the front side member 1.
In addition to forming a fragile portion 20 that promotes bulging deformation of c toward the outside of the cross section, a deformation induction that induces bulging deformation of the vertical walls 3b and 3c in response to a load input to the front of the bent portion 1B to the rear. While the means 30 is provided, the deformation suppressing means 40 is provided from the inclined portion 1C to the extension portion 1D.

As shown in FIG. 4, the fragile portion 20 has a welded W portion connecting the lower member 3 and the upper member 4, and the left and right vertical walls 3b and 3c of the front side member 1 having a closed cross section.
Of the lower ridge line portions 3e and 3f at the boundary between the lower wall 3d and the lower wall 3d at the bent portion 1B.
And an embossed portion 23 as an extension permitting portion formed at a position corresponding to the bent portion 1B of at least the upper wall 4c of the front side member 1.

That is, the welded W portion, which is one of the constituent elements of the fragile portion 20, is a portion whose strength is lower than that of the other portion due to the influence of welding heat. Because of the upper end portions of the left and right vertical walls 3b, 3c of the member 3, the strength in the vicinity of the upper ridge portions 3g, 3h of the front side member 1 is locally reduced.

In addition, the thin ridge line portions 21 and 22 which are another constituent element of the fragile portion 20 are the lower ridge line portions 3.
The strength is locally reduced due to the thinning of e and 3f.

Further, in the embossed portion 23, which is the remaining constituent element of the fragile portion 20, the upper wall 4c of the upper member 4 is formed in a substantially elliptical shape at a portion corresponding to the bent portion 1B. 4c is recessed downward, and when the vertical walls 3b and 3c of the bent portion 1B are deformed, the embossed portion 23 allows extensional deformation to positively deform the vertical walls 3b and 3c. ing.

Therefore, when the collision load F from the front of the vehicle is input from the front of the front side member 1, 2 in FIG.
As shown by the dotted line, the left and right vertical walls 3b and 3c of the bent portion 1B are positively bulged and deformed outward in cross section by the fragile portion 20.

As shown in FIGS. 2 and 6, the deformation inducing means 30 is located immediately in front of the bent portion 1B and is integrally formed with a lateral rib 31 which crosses the closed cross section of the front side member 1. The horizontal rib 31 is formed by a vertical rib 32 which is connected to a substantially central portion of the horizontal rib 31 in the transverse direction and extends forward of the vehicle body.

Incidentally, the horizontal ribs 31 and the vertical ribs 32.
In the portion where the horizontal rib 31 is formed, two other sub-lateral ribs 31a and 31b are provided parallel to each other at a predetermined distance toward the front of the horizontal rib 31, and the vertical rib 32 is the frontmost sub-lateral rib 31b and the deformation inducing means 30. It is provided across the horizontal rib 31 used as.

Further, the rear end of the front member 2 inserted into the front portions of the lower member 3 and the upper member 4 is in contact with the front surface of the sub-lateral rib 31b, and the front member 2 is input. The collision load F from the front acts on the horizontal rib 31 via the sub-lateral rib 31b and the vertical rib 32.

A boss portion 33 having a central hole 33a is formed at the intersection of the vertical rib 32 and the sub-lateral rib 31a.

As shown in FIG. 2, the deformation suppressing means 40 is constituted by a plurality of ribs 41, 41, ... Connecting the facing vertical walls 3b, 3c from the inclined portion 1C to the extension portion 1D. I am doing it.

That is, the ribs 41, 41, ... Are formed at the same time when the lower member 3 is formed by casting, and are integrated with the vertical walls 3b, 3c and the lower wall 3d of the lower member 3, From the inclined portion 1C of the lower member 3 to the extension portion 1
A plurality of ribs 41, 41 ... Are erected upright in a bellows-like or irregular bellows-like manner over a section D, and a load F from the front is applied.
On the other hand, the rigidity of the inclined portion 1C is ensured so that it is not easily deformed.

In the front side member structure of the first embodiment having the above-described structure, the collision load F is input to the front side member 1 from the front due to the frontal collision, and the axial crushing of the front member 2 is substantially completed, and the rear portion is rear-parted. When the transmission load F to the bending rib 1 increases, the load F is first input to the vertical ribs 32 of the deformation inducing means 30 provided in front of the bent portion 1B, and the horizontal ribs 31 of the horizontal ribs 31 as shown by the two-dot chain line in FIG. Since the central portion is deformed rearward, a moment M that tends to push the front portions of the vertical walls 3b and 3c of the bent portion 1B outward in the cross section is generated.

At this time, in the bent portion 1B, the welding W applied in the vicinity of the upper ridge portions 3g and 3h and the lower ridge portion 3 are formed.
A fragile portion 20 including thin ridgeline portions 21 and 22 of e and 3f and an embossed portion 23 formed on the upper wall 4c of the upper member 4.
Since the bending portion 1B is deformed by the moment M, the vertical walls 3b and 3c are bulged and deformed outward in the cross section, and the bending portion 1B is deformed as shown by a two-dot chain line in FIG. Since the cross-section is deformed in a flattening direction with respect to the direction (the bending direction of the bent portion 1B) as shown by the chain double-dashed line in FIGS. 4 and 7, the second moment of area of the bent portion 1B becomes small.

By thus reducing the second moment of area of the bent portion 1B, the bending deformation of the bent portion 1B in the bending direction is positively performed, whereby the collision energy transmitted to the rear portion of the front side member 1 is generated. Can be effectively absorbed.

By the way, in this embodiment, the fragile portion 20 is used.
Welding W, thin-walled ridge portions 21, 22 and embossed portion 23
Since each of the three constituent elements is provided, the respective constituent elements can cause the vertical walls 3b and 3c of the bent portion 1B to bulge and deform more reliably and easily. Without configuring the fragile portion 20 by
The fragile portion 20 can also be configured by at least one of each component.

In addition to the fact that the bent portion 1B is positively deformed and can absorb the collision energy as described above, the ribs 41, 41 are provided on the inclined portion 1C of the front side member 1.
.. are provided to configure the deformation suppressing means 40, the deformation of the inclined portion 1C due to the collision load F is suppressed,
As a result, the deformation of the dash panel 10 toward the rear of the vehicle body can be prevented or suppressed, so that the deformation of the cabin can be effectively prevented.

Further, in this embodiment, since the deformation of the cabin at the time of a frontal collision can be prevented as described above, it is not necessary to provide many reinforcing members on the front side member 1, the dash panel 10 or the floor 11, so that the weight of the vehicle body is increased. Can be suppressed.

8 to 13 show a second embodiment of the present invention, and the same components as those of the first embodiment will be designated by the same reference numerals and overlapping description will be omitted.

FIG. 8 is a side view showing a mounting state of the front side member, FIG. 9 is an exploded perspective view of the front side member, FIG. 10 is an enlarged sectional view taken along line EE in FIG. 8, and FIG. 11 is FIG. 8 is an enlarged cross-sectional view taken along line FF in FIG. 8, FIG. 12 is an enlarged cross-sectional view taken along line GG in FIG. 8, and FIG.
It is an expanded sectional view along the H line.

Similar to the first embodiment, the front side member 100 of the second embodiment is arranged so as to extend in the vehicle front-rear direction on both sides in the vehicle width direction of the front compartment, as shown in FIG. Of the substantially straight member main body 100A, an inclined portion 100C which is inclined downward along the inclination of the toe board portion of the dash panel 10 at the rear of the bent portion 100B, and the lower surface of the floor 11 following the inclined portion 100C. Extension part 100 wrapped around
It is configured as a closed cross-section structure including D.

The front side member 100 is constructed by bending plate members and connecting them to each other. The main components of the front side member 100 are a side member 101 having a U-shaped cross section, and an open portion of the side member 101. 101a
It includes a strip-shaped plate closing member 102 for closing and a rearward tilting member 103 having a U-shaped cross section.

As shown in FIG. 9, the side member 101 is formed in a U-shape in cross section so that the outer side in the vehicle width direction (the right side in the figure) is opened, and the upper and lower ends of the open portion 101a of the side member 101. Is bent upward and downward to form the closing member 10
Flanges 101b and 101c for connecting the two are provided.

Then, the flanges 101b, 101
The upper and lower end portions of the flat belt-shaped closing member 102 are spot-welded to c, so that the side member 101 and the closing member 102
The combination of and forms a closed cross section.

The side member 101 and the closing member 10
Reference numeral 2 integrally forms a front portion Fr that is axially crushed by a collision load input from the front (the front side in the drawing) and a rear portion Rr that is coupled to the rear tilt member 103.
A thin plate material is used for each front portion Fr, and a thick plate material is used for the rear portion Rr. A blank material obtained by joining the thin plate material and the thick plate material by laser welding or the like is press-formed to form the side member 101 and the side member. Closing member 1
02 is formed.

The rear tilting member 103 is formed in a U-shaped cross-section having an open portion 103a at the top, and the front half of the rear tilting member 103 is connected to the side member 101 in a closed cross section as shown in FIG. It is connected by spot welding to the lower side of the rear portion Rr of the closing member 102.

At this time, the side wall of the side member 101 and the closing member 102 are the vertical walls 101d and 102 of the bent portion 100B.
a (see FIG. 11).

The rearward tilting member 103 has flanges 103b provided on both sides of the open portion 103a.
As shown in FIG. 12, 103 c is spot-welded to the dash panel 10 to form a closed cross-section structure.

Also in the second embodiment, the vertical wall 10 of the bent portion 100B is provided at the bent portion 100B along the inclined surface of the dash panel 10 of the front side member 100.
Deformation-inducing means for forming a fragile portion 110 that allows bulging deformation of 1d, 102a outward in cross section and for bulging deformation of the vertical walls 101d, 102a of the bending portion 100B in front of the bending portion 100B. While 120 is provided, deformation suppressing means 130 is provided from the inclined portion 100C to the extension portion 100D.

As shown in FIGS. 9 and 11, the fragile portion 110 has a lower wall 103d of the bent portion 100B which is a first reinforcing member for increasing the strength of the fragile portion 110, as compared with the vertical walls 101d and 102a. A reinforcement 111 is provided and configured.

The first reinforcement 111 is formed integrally with a third reinforcement 131 described later,
The details will be described later together with the description of the third reinforcement 131.

The deformation inducing means 120 is shown in FIGS.
As shown in FIG.
Curved parts 1 projecting inward in cross sections 1d and 102a, respectively
21 and 121a, the curved portions 121,
The second reinforcement 122 is provided as a second reinforcing member having a shape that conforms to the inner surface shape of the portion where the 121a is formed, and the second reinforcement 122 is provided in the curved portion 12.
1, 121a is straddled and is connected by front and rear of them by spot welding.

That is, the second reinforcement 122 is
The side member 101 is bent in a substantially U shape along the inner side thereof, and an escape portion 123 is formed along the curved portion 121 in the central portion of the one wall 122a thereof.
Flange 12 formed by bending the tips of 22b and 122c
An escape portion 123a is formed along the shape of the curved portion 121a at the center of 2d and 122e.

Then, as shown in FIG. 13, the relief portions 123 and 123a are overlapped with the curved portions 121 and 121a, and the second reinforcement 122 is spot-welded to the side member 101 and the closing member 102 to be joined. .

At this time, as shown in FIG. 10, the upper flange 122d of the second reinforcement 122 is spot-welded by sandwiching it between the upper flange 101b of the side member 101 and the closing member 102, and the The flange 122e is spot-welded to the inside of one vertical wall 103e of the rearward tilt member 103.

Further, the curved portions 121 and 121a are formed on both vertical walls 103f and 103e at the front of the rearward inclination member 103.
The curved portions 124 and 124a are formed along the line.

The deformation suppressing means 130 has the structure shown in FIG. 9 and FIG.
As shown in FIG. 7, a third reinforcement 131 is provided as a third reinforcing member that connects the dash panel 10 serving as a lower wall and the lower wall 103d of the rearward tilting member 103, as a third reinforcing member.

The third reinforcement 131 is formed in a U-shaped cross section along the inside of the entire region of the inclined portion 100C of the rearwardly inclined member 103, and the flanges 131b and 131c are formed on both sides of the open portion 131a. As shown in FIG. 12, the flanges 103b, 1
It is sandwiched between 03c and the dash panel 10 and spot-welded.

The lower wall 131d of the third reinforcement 131 is extended forward (toward the front side in FIG. 9), and the extended portion constitutes the first reinforcement 111, and the first reinforcement 111 is formed. As shown in FIG.
The lower wall 103d of 00B is spot-welded.

Therefore, in the bent portion 100B, the strength of the lower wall 103d is increased by the first reinforcement 111, so that the vertical wall 101d, against the collision load F from the front.
The deformation of 102a is preferentially deformed.

In the front side member structure of the second embodiment having the above structure, the collision load F is input to the front side member 100 from the front due to the frontal collision, and the side member 101 and the closing member 102 having a closed cross section are formed. And the axial crushing of the front part Fr is almost completed, and the transmission load F to the rear part Rr
Becomes larger, the bending portion 12 of the deformation inducing means 120 to which the second reinforcement 122 is attached as shown in FIG.
1, 121a and the escape portions 123, 123a generate a deforming force F1 that causes the rear portion of the second reinforcement 122 to move,
That is, the vertical walls 101d, 102 at the front end of the bent portion 100B
A moment M that pushes a toward the outside of the cross section to open it is generated.

Then, the bent portion 100B is moved to the lower wall 103 by the fragile portion 110 provided with the first reinforcement 111.
Since the strength of the vertical walls 101d and 102a is lower than that of the vertical walls 101d and 102d, as shown by the chain double-dashed line in FIG.
1d and 102a are bulged and deformed to the outside of the cross section,
The second moment of area with respect to the bending direction of 0B becomes small.

Therefore, the bending deformation of the bending portion 1B in the bending direction is positively performed, whereby the collision energy transmitted to the rear portion of the front side member 1 can be effectively absorbed, and the front side member can be effectively absorbed. 10
Since the deformation suppressing means 130 provided with the third reinforcement 131 is provided in the inclined portion 100C of 0, the deformation of the inclined portion 100C can be suppressed to prevent or suppress the deformation of the dash panel 10 rearward of the vehicle body. Therefore, the deformation of the cabin can be effectively prevented.

The front side member structure of the present invention has been described by taking the first and second embodiments as an example. Of course, the present invention is not limited to these embodiments and various implementations can be made without departing from the gist of the present invention. A form can be adopted.

[Brief description of drawings]

FIG. 1 is a side view showing a mounted state of a front side member according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a front side member according to the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view taken along the line AA in FIG.

FIG. 4 is an enlarged cross-sectional view taken along the line BB in FIG.

5 is an enlarged cross-sectional view taken along the line CC in FIG.

FIG. 6 is an enlarged cross-sectional view taken along the line DD in FIG.

FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 4 showing a deformed state of the bent portion in the first embodiment of the present invention.

FIG. 8 is a side view showing a mounted state of a front side member according to the second embodiment of the present invention.

FIG. 9 is an exploded perspective view of a front side member according to the second embodiment of the present invention.

10 is an enlarged cross-sectional view taken along the line EE in FIG.

11 is an enlarged cross-sectional view taken along the line FF in FIG.

FIG. 12 is an enlarged cross-sectional view taken along the line GG in FIG.

13 is an enlarged cross-sectional view taken along the line HH in FIG.

[Explanation of symbols]

1,100 Front side member 1A, 100A member body 1B, 100B Bend 1C, 100C slope 1D, 100D extension section 3b, 3c, 101d, 102a Vertical wall of bent portion 20,110 fragile part 21,22 Thin ridge 23 Embossed part (stretchable part) 30,120 Deformation inducing means 31 horizontal ribs 32 vertical ribs 40,130 Deformation suppressing means 41 rib 111 First Reinforcement (First Reinforcement Member) 121, 121a curved part 122 Second Reinforcement (Second Reinforcement Member) 131 Third Reinforcement (Third Reinforcing Member) W welding

Claims (10)

[Claims] 1. An extension part is formed on both sides of the front compartment in the vehicle width direction so as to extend in the front-rear direction of the vehicle body, and an extension part is formed in the rear part around the lower surface of the floor via an inclined part along the inclined surface of the dash panel. In a front side member structure having a closed cross-section structure, a fragile portion that promotes outward bulging deformation of a vertical wall of the bent portion at the bent portion at the boundary between the front member body and the inclined portion of the front side member. A deformation inducing means for inducing bulging deformation of the vertical wall with respect to an axial input load is provided in front of the bent portion, and a deformation suppressing means is provided from the inclined portion to the extension portion. Front side member structure characterized by 2. The front side member includes a lower member formed of a light alloy casting in a U-shaped cross-section, and an upper member formed of a light alloy plate member which is joined to cover an upper open portion of the lower member. The front side member structure according to claim 1, wherein the front side member structure has a closed cross section. 3. The front side member structure according to claim 2, wherein the lower member and the upper member are welded to each other at least at the bent portion and are joined to each other, and the welded portion is a part of the fragile portion. . 4. A wall thickness of a ridgeline portion at a boundary between a lower wall and a vertical wall of a front side member having a closed cross section is thinned at least at the bent portion, and the thin ridgeline portion is a weak portion. The front side member structure according to claim 2 or 3. 5. The deformation inducing means is integrally formed at a front portion of the bent portion across a closed cross section of the front side member, and is connected to a substantially central portion of the transverse rib in a transverse direction, and a front portion of the vehicle body. The front side member structure according to any one of claims 2 to 4, wherein the front side member structure is configured by a vertical rib that extends to a horizontal direction and that transmits an axial input load to the horizontal rib. 6. The deformation suppressing means is constituted by a plurality of ribs connecting between the facing vertical walls extending from the inclined portion to the extension portion, as claimed in any one of claims 2 to 5. Front side member structure. 7. The front side according to claim 2, wherein the fragile portion includes an extension allowing portion formed at a position corresponding to the bent portion of at least an upper wall of the front side member. Member structure. 8. A member for forming a front-side member main body including at least a bent portion of a front side member with a plate material, and for forming the fragile portion on a lower wall of the bent portion to have higher strength than a vertical wall. The front side member structure according to claim 1, wherein the front side member structure is configured by providing one reinforcing member. 9. The deformation inducing means is provided with a curved portion projecting inward in cross section on opposing vertical walls in front of the bent portion, and a second reinforcing member having a shape along the portion where the curved portion is formed is provided. 9. The second reinforcing member is configured by straddling the curved portion and being connected to the front and rear of the curved portion.
Front side member structure described in. 10. The deformation suppressing means is constituted by a third reinforcing member that is fitted and arranged along the inner peripheral surface of the inclined portion to the extension portion along the inner peripheral surface thereof. Front side member structure.