JP2004322719A - Vehicle front part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the securement of safety at a front surface collision and the light weight of a vehicle compatible. <P>SOLUTION: An engine under cover 36 is constituted of a resin material having high strength and the front end thereof is fastened to a radiator support lower 26 with a bolt. The rear end of the engine under cover 36 is fixed to the lower part side of the rear end of a kick part 30 of a front side member 10. Accordingly, at the front surface collision, a load is inputted from the radiator support lower 26 to the engine under cover 36 and predetermined energy is absorbed by deformation. As a result, since a load burden to the front side member 10 is reduced and a reinforcement or the like can be reduced, the light weight of the vehicle can be obtained. Safety at the front surface collision is also secured since the engine under cover 36 functions as an energy absorbing member. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle front structure including a front side member, a radiator support, and an engine under cover.
[0002]
[Prior art]
A pair of front side members are disposed on both sides of the front part of the vehicle body with the longitudinal direction of the vehicle being in the longitudinal direction. This front side member is a vehicle structural member that connects the front bumper reinforcement and the rocker panel. A bent portion called a kick portion is set.
[0003]
[Patent Document 1]
JP-A-2002-120768
[Problems to be solved by the invention]
Here, at the time of a frontal collision, particularly at the time of an offset collision, a large collision load is input to the front side members. The collision load is mainly supported by the front side members, and the cabin is designed to be protected by this. However, in order to protect the cabin, it is necessary to increase the rigidity of the front side members. For this purpose, it is necessary to take measures such as adding a reinforcing component to the front side member. However, there is a problem that the weight of the vehicle increases accordingly.
[0005]
On the other hand, it is also important to reduce the weight of the vehicle to improve fuel efficiency.
[0006]
The present invention has been made in view of the above-described circumstances, and has as its object to provide a vehicle body front structure capable of achieving both safety during a frontal collision and reduction in vehicle weight.
[0007]
[Means for Solving the Problems]
The vehicle front structure according to the present invention as set forth in claim 1 is provided between a pair of front side members arranged on both sides of the vehicle body front portion with the vehicle front-rear direction as a longitudinal direction, and front end portions of the pair of front side members. A radiator support arranged including the vehicle width direction as a longitudinal direction and including an upper portion and a lower portion, and a radiator support including an upper portion and a lower portion. A front end of the engine under cover is fixed to a lower portion of the radiator support, and a rear end of the engine under cover is fixed to a lower rear end of the front side member or a peripheral member thereof.
[0008]
According to a second aspect of the present invention, there is provided a vehicle front structure according to the first aspect, wherein a bead for improving energy absorption efficiency or a plate thickness changing portion corresponding to the bead is provided on the engine under cover. It is formed along the direction.
[0009]
According to a third aspect of the present invention, in the vehicle front structure according to the first or second aspect, the input load from the lower portion of the radiator support is applied to the engine under cover. It is characterized in that a load dispersing portion for dispersing along the surface is formed.
[0010]
According to the first aspect of the present invention, at the time of a frontal collision, the collision load is input to the upper portion and the lower portion of the radiator support. Of these, the collision load input to the lower portion is input to the front side member as it is in a conventional structure.
[0011]
However, according to the present invention, the front end of the engine under cover is fixed to the lower portion of the radiator support, and the rear end of the engine under cover is fixed to the lower rear end of the front side member or a peripheral member thereof. Part of the load input to the lower portion is transmitted to the engine under cover, and the rest is transmitted to the front side member.
[0012]
In the above process, the engine under cover is deformed (buckling, etc.) in the vehicle front-rear direction by receiving the supporting reaction force at the fixed point at the rear end thereof, whereby part of the energy input to the lower portion of the radiator support is reduced. Absorbed. As a result, the load on the front side member is reduced, and the degree of reinforcement is correspondingly reduced. Therefore, the weight of the vehicle can be reduced. In addition, since the engine under cover and the front side member are deformed, the energy absorbing effect at the time of a frontal collision is sufficiently exhibited, so that the safety at the time of a frontal collision is also ensured.
[0013]
That is, in the present invention, by actively utilizing the engine under cover as an energy absorbing member, it is possible to secure the energy absorbing performance at the time of a frontal collision and reduce the load on the front side member.
[0014]
According to the second aspect of the present invention, since a bead for improving energy absorption efficiency or a plate thickness changing portion corresponding to the bead is formed in the engine under cover along the vehicle front-rear direction, the engine under cover can be used at the time of a frontal collision. The energy absorption efficiency is enhanced by the engine under cover.
[0015]
According to the third aspect of the present invention, the engine under cover is provided with a load dispersing portion for dispersing the input load from the lower portion of the radiator support along the surface of the engine under cover. However, the load can be transmitted to the anti-collision side of the engine undercover, and the engine undercover can be deformed in a wide range. For this reason, the energy absorption efficiency by the engine undercover at the time of an offset collision is enhanced.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a vehicle front structure according to the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a perspective view of the assembled state of the vehicle front structure according to the present embodiment, FIG. 2 is a schematic plan view of the vehicle body front structure, and FIG. Shows a schematic side view thereof.
[0018]
As shown in these drawings, a pair of front side members 10 having a longitudinal direction in the vehicle front-rear direction are disposed on both sides of the front part of the vehicle body. A front end of the front side member 10 is connected to an end of a front bumper reinforcement 12 arranged with the vehicle width direction as a longitudinal direction. The rear end of the front side member 10 is connected to the front end of a rocker 14 that is disposed at the lower end of the vehicle body side (position of the side door) with the longitudinal direction of the vehicle being the longitudinal direction. Further, a so-called well-shaped sub-frame 20 is attached to the pair of front side members 10 via a support 16 and a bush 18.
[0019]
A radiator support 22 having a longitudinal direction in the vehicle width direction is provided between the front end portions of the pair of front side members 10. The radiator support 22 is formed substantially in the shape of a "sun" in a front view, and includes a radiator support upper 24 and a radiator support lower 26 which are arranged vertically in parallel with each other, and three vertical columns connecting the both in the vehicle vertical direction. 28.
[0020]
Further, a bent portion called a kick portion 30 is set in an intermediate portion in the longitudinal direction of the front side member 10 described above. The kick portion 30 is formed because the arrangement height of the rocker 14 is lower than the arrangement height of the front bumper reinforcement 12.
[0021]
Above the pair of front side members 10, a straight apron upper member 32 whose longitudinal direction is the vehicle front-rear direction is disposed. The front end of the apron upper member 32 is connected to the end of the radiator support upper 24, and the rear end of the apron upper member 32 is connected to the upper end of the front pillar lower 34.
[0022]
An engine under cover 36 is provided on the bottom side of the front portion of the vehicle body (below the subframe 20), and will be described in detail below.
[0023]
As shown in FIG. 4, the engine under cover 36 is formed in a flat plate shape, and has a total length from the radiator support lower 26 to the lower rear end of the kick portion 30 of the front side member 10. Further, the engine under cover 36 of the present embodiment is formed of a high-strength resin material mixed with glass fiber or the like.
[0024]
As shown in FIGS. 1 and 3, the front end of the above-described engine under cover 36 is fixed to the lower end of the radiator support lower 26 with a bolt 38 and a weld nut 40. The radiator support lower 26 has a hat-shaped cross section with an open lower surface, but is closed by attaching an engine under cover 36.
[0025]
On the other hand, the rear end of the engine under cover 36 is fixed to the lower rear end of the front side member 10 by bolts 42 and weld nuts (not shown). In addition, as described later, the front end and the rear end of the engine under cover 36 can be fixed by a configuration other than the fastener, and the description here is only an example.
[0026]
Next, the operation and effect of the present embodiment will be described.
[0027]
At the time of a frontal collision, the collision load is input to a radiator support upper 24 and a radiator support lower 26 of the radiator support 22. Among these, the collision load input to the radiator support lower 26 is input to the front side member 10 as it is in a conventional structure.
[0028]
However, in the present embodiment, the length of the engine under cover 36 in the front-rear direction is increased, the front end of the engine under cover 36 is fixed to the radiator support lower 26, and the rear end of the kick portion 30 of the front side member 10 is located at the lower rear end. Since the rear end of the engine under cover 36 is fixed, part of the load input to the radiator support lower 26 is transmitted to the engine under cover 36, and the rest is transmitted to the front side member 10.
[0029]
In the above process, the engine under cover 36 is deformed (buckling, etc.) in the vehicle front-rear direction by receiving a supporting reaction force at a fixed point at the rear end thereof, whereby a part of the energy input to the radiator support lower 26 is reduced. Absorbed. As a result, the load on the front side member 10 is reduced, and the degree of reinforcement of the front side member 10 can be reduced accordingly. Therefore, the weight of the vehicle can be reduced. Further, since both the engine under cover 36 and the front side member 10 are deformed, the energy absorbing effect at the time of a frontal collision is sufficiently exhibited, so that the safety at the time of a frontal collision is also ensured.
[0030]
That is, in the vehicle front structure according to the present embodiment, the engine under cover 36 is positively utilized as an energy absorbing member, thereby ensuring the energy absorbing performance at the time of a frontal collision and reducing the load burden on the front side member 10. Can be reduced. As a result, according to the present embodiment, it is possible to achieve both safety during a frontal collision and weight reduction of the vehicle.
[0031]
FIG. 5 shows an evaluation (test result) when the vehicle front structure according to the present embodiment is applied. A graph A shown by a solid line is an FT curve (F represents an input load to the front side member, and T represents time) when the vehicle front structure according to the present embodiment is applied, and is a graph shown by a two-dot chain line. B is an FT curve when the vehicle front structure before improvement is used.
[0032]
As can be seen from a comparison between the two, the peak value decreases in both the primary peak (P portion) and the secondary peak (Q portion). In addition, the input load after the secondary peak (R section) also decreased, and good results were obtained.
[0033]
In the above-described embodiment, the engine under cover 36 is made of a high-strength resin material. However, the engine under cover 36 is not necessarily made of a resin material, but may be made of a steel plate or an aluminum alloy material.
[0034]
Further, in the above-described embodiment, the plate-shaped engine under cover 36 is used. However, the present invention is not limited to this, and a bead extending in the vehicle front-rear direction may be formed integrally or separately. Further, instead of the bead, a configuration may be adopted in which the thickness of the portion is increased to form a thick portion as a thickness change portion. When the bead and the thick portion are formed in this manner, the rigidity of the engine under cover 36 in the vehicle front-rear direction is increased, so that the energy absorption efficiency of the engine under cover 36 at the time of a frontal collision is enhanced. As a result, it is possible to further ensure safety during a frontal collision and reduce the weight of the vehicle.
[0035]
Further, in the above-described embodiment, the plate-shaped engine under cover 36 is used. However, the present invention is not limited to this, and the input load from the radiator support lower 26 is dispersed to the anti-collision side along the surface of the engine under cover 36. The load distribution portion may be formed on the engine under cover 36.
[0036]
For example, a substantially M-shaped bead 44 may be formed in plan view as shown by a two-dot chain line in FIG. The bead 44 includes a pair of vertical beads 44A formed in parallel in the vehicle front-rear direction, and a V-shaped oblique bead 44B connecting front ends of these vertical beads 44A.
[0037]
According to the above configuration, when the vehicle collides with the collision body 46 at an offset, focusing only on the load input to the engine under cover 36 of the input load F, a part of the load is input to the vertical bead 44A on the right side in the drawing. Then, the right side of the engine under cover 36 is deformed. On the other hand, the rest of the load is input to the oblique bead 44B on the right side in the figure, and deforms the central portion of the engine under cover 36. Thus, at the time of an offset collision, the input load F can be dispersed in the width direction of the engine undercover 36 to deform the engine undercover 36 in a wide range. Therefore, the energy absorption efficiency of the engine under cover 36 at the time of an offset collision can be increased. As a result, it is possible to further ensure safety during a frontal collision and reduce the weight of the vehicle. It should be noted that a case where an offset collision occurs on the left side of the front part of the vehicle can be considered in the same manner as described above.
[0038]
The M-shaped bead 44 is an example of the bead according to the second aspect, and is also an example of the load distribution section according to the third aspect. Examples of such a bead or a load dispersing portion are not limited to the M-shaped bead 44, but can be realized in various configurations. For example, in place of the M-shaped bead 44, a "sun" -shaped bead may be formed in a plan view, or a truss-shaped bead in which a W-shaped bead or a triangle is continuous in the vehicle width direction. May be.
[0039]
In the above-described embodiment, both the front end and the rear end of the engine undercover 36 are fixed to the vehicle body component by bolting. However, the present invention is not limited to this, and various fixing structures can be adopted. It is. For example, as shown in FIG. 6, a hook-shaped hook portion 50 is provided in advance on a vehicle body component (here, the front cross member 48) which is a fixing partner of the rear end of the engine under cover 36, and the hook is provided. A configuration may be adopted in which the rear end of the engine under cover 36 is fitted (locked) to the portion 50 in the direction of the arrow, and then only the front end is fastened with the bolt 38 and the weld nut 40. Alternatively, a configuration may be adopted in which a part or the entirety of the fixing portion of the engine undercover 36 is bonded using an adhesive.
[0040]
Further, in the above-described embodiment, the rear end of the engine under cover 36 is fixed to the lower rear end of the kick portion 30 of the front side member 10, but the fixing partner is not limited to this, and for example, the engine mount Or may be fixed to the front cross member 48 as shown in FIG. It should be noted that the "(lower rear end of the front side member or its peripheral member)" of the first aspect includes such an engine mount and a front cross member.
[0041]
【The invention's effect】
As described above, the vehicle front structure according to the first aspect of the present invention fixes the front end of the engine under cover which is formed in a plate shape and has high rigidity to the lower portion of the radiator support, and Since the rear end of the engine under cover is fixed to the lower part of the rear end of the front side member or its peripheral members, the engine under cover can be actively used as an energy absorbing member and the load on the front side member can be reduced. As a result, there is an excellent effect that it is possible to achieve both security during a frontal collision and weight reduction of the vehicle.
[0042]
According to a second aspect of the present invention, there is provided a vehicle front structure according to the first aspect, wherein a bead for improving energy absorption efficiency or a plate thickness changing portion corresponding to the bead is provided in the engine under cover along the vehicle longitudinal direction. As a result, the efficiency of energy absorption by the engine under cover during a frontal collision can be enhanced, and as a result, there is an excellent effect that safety during a frontal collision and vehicle weight can be further reduced.
[0043]
According to a third aspect of the present invention, in the vehicle front structure according to the first or second aspect, the input load from the lower portion of the radiator support is distributed to the engine under cover along the surface of the engine under cover. Since the load dispersing portion is formed, the energy absorption efficiency of the engine under cover at the time of an offset collision can be increased, and as a result, the safety at the time of a frontal collision and the vehicle weight can be further reduced. Has an effect.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of a vehicle front structure according to an embodiment.
FIG. 2 is a schematic plan view of a vehicle front structure according to the embodiment.
FIG. 3 is a schematic side view of a vehicle front structure according to the embodiment.
FIG. 4 is a schematic plan view of the engine under cover shown in FIG.
FIG. 5 is a graph showing a result of an evaluation test of the vehicle front structure according to the embodiment.
FIG. 6 is a longitudinal sectional view showing another fixing structure of the engine under cover.
[Explanation of symbols]
10 Front side member 22 Radiator support 26 Radiator support lower 36 Engine under cover 44 Bead 44A Vertical bead (bead)
44B diagonal bead (load dispersion part)
48 Front cross member (peripheral member)

Claims (3)

A pair of front side members arranged on both sides of the front of the vehicle body with the longitudinal direction of the vehicle in the longitudinal direction,
A radiator support disposed between the front end portions of the pair of front side members with the vehicle width direction as a longitudinal direction, and including an upper portion and a lower portion;
The vehicle body front structure comprising:
A front end of the plate-shaped and high-rigidity engine under cover is fixed to a lower portion of the radiator support, and a rear end of the engine under cover is located at a lower rear end of the front side member or in the vicinity thereof. Fixed to the member,
A vehicle body front structure characterized by the following. In the engine under cover, a bead for increasing energy absorption efficiency or a plate thickness changing portion corresponding to the bead is formed along the vehicle front-rear direction.
The vehicle front structure according to claim 1, wherein: In the engine under cover, a load distribution unit that distributes an input load from a lower portion of the radiator support along a surface of the engine under cover is formed.
The vehicle front structure according to claim 1 or 2, wherein:

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