JPH11342811A - Front body structure of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front body structure used for an automobile and capable of reducing deceleration at low-speed collision without requiring an extra space or adding parts. SOLUTION: A front body structure for an automobile is formed by connecting the front ends of a right and left side member 2, 2 extended in the back and forth directions of an automobile to each other through a reinforcement 20 extended in the width direction of the automobile. Where, the reinforcement 20 is of a closed cross sectional shape consisting of an outer reinforcement 21 in generally hut shape in its transverse section and an inner reinforcement 22 in a band plate shape. The outer reinforcement 21 has a plate thickness t1 thinner than the plate thickness t2 of the inner reinforcement 22. The result reduces deceleration at low-speed collision.

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 motor vehicle, and more particularly to a shock absorbing structure capable of reducing deceleration in a low-speed collision.

[0002]

2. Description of the Related Art In general, an automobile adopts a structure in which the energy at the time of collision is absorbed by compressing and deforming left and right side members in the axial direction, thereby suppressing the influence on the vehicle compartment. To prevent the side members from falling down in the vehicle width direction due to the collision, for example, FIGS.
As shown in the figure, a bumper reinforcement 5 extending between the front end surfaces of the left and right side members 52, 52 in the vehicle width direction.
3 may be combined. Incidentally, 54 is a front bumper cover, and 55 is a front cross member.

[0003] Such a bumper reinforcement 53
Therefore, since a rigidity capable of reliably transmitting the force F to the side member at the time of a collision is required, a closed cross section is formed by the outer reinforcement 53a having a hat-shaped cross section and the inner reinforcement 53b having a strip shape. In some cases, the structure is formed.

If the rigidity of the bumper reinforcement 53 is excessively increased, the impact force F is transmitted to the side member 52 as it is. In such a case, the airbag system may be activated.

[0005] As a structure capable of avoiding the operation of the airbag at the time of such a low-speed collision, Japanese Patent Application Laid-Open No. 9-90905 discloses
No. 66785 discloses that the first,
A structure has been proposed in which a second divided body is joined, and the first divided body is projected forward of the vehicle body from the second divided body, so that the first divided body absorbs collision energy at low speed.

[0006]

However, in the above-mentioned conventional publication, the first and second divided bodies are joined to the front end of the side frame, and the first divided body is further projected forward of the vehicle body. However, it is necessary to secure an extra space, which causes a problem that the area around the front end of the vehicle body becomes large. There is also a problem that the number of parts increases by the amount of separately adding the first divided body for absorbing the light collision energy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and does not require an extra space and does not require any additional components, and can reduce the deceleration in a low-speed collision. It is intended to provide.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a front body structure of an automobile in which front end surfaces of left and right side members extending in a vehicle longitudinal direction are connected to each other by a reinforcement extending in a vehicle width direction. The reinforcement is a closed cross-section having an outer reinforcement having a substantially hat-shaped cross section and a strip-shaped inner reinforcement, and the thickness of the outer reinforcement is set to the inner reinforcement. The thickness of the outer reinforcement is smaller than the thickness of the outer reinforcement, and the deceleration at the time of low-speed collision is reduced by the outer reinforcement.

[0009]

According to the front body structure of the present invention, the thickness of the outer reinforcement is made smaller than that of the inner reinforcement, so that a relatively small impact force at the time of a low-speed collision is reduced. It is absorbed by the deformation of the outer reinforcement before being transmitted to the nail reinforcement, whereby the deceleration at the time of a low-speed collision can be reduced, and the transmission of the impact force to the side members can be suppressed.
Thus, for example, when applied to a vehicle equipped with an airbag system, it is possible to prevent the airbag from operating during a low-speed collision.

Further, since a large impact force is transmitted to the left and right side members via the thick inner reinforcement, collision energy can be received by the entire vehicle body, and the energy absorption efficiency can be improved. be able to.

In the present invention, since the outer reinforcement has a structure in which only the thickness of the outer reinforcement is changed, it is not necessary to secure an extra space unlike the conventional publication, and it is possible to avoid an increase in size around the front end of the vehicle body. In addition, there is an effect that addition of another component is unnecessary, and cost can be reduced.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 are views for explaining a front body structure of an automobile according to an embodiment of the present invention. FIGS. 1 and 2 are sectional views of the front body, and FIG. 3 is an exploded perspective view of a body frame. FIG. 4 is a schematic plan view showing an energy transmission path at the time of a collision.

In FIG. 1, reference numeral 1 denotes a vehicle body frame constituting a lower part of a vehicle body. The vehicle body frame 1 is a front cross extending in the vehicle width direction between the front ends of left and right side members 2 and 2 extending in the vehicle front-rear direction. This is a schematic structure in which a member 3, a floor cross member 4 is provided between the center portions, and a rear cross member 5 is provided between the rear end portions.

The front cross member 3 has a hat-like cross section that opens downward, and both end flanges 3 a of the cross member 3 are joined to the inner side wall 2 a of the side member 2. Suspension towers 6, 6 for supporting shock absorbers (not shown) of the front wheel suspension are joined to the front outer wall 2b of each side member 2.

The floor cross member 4 has a hat shape with a cross section that opens upward, and has a recess 4a cut out on the left and right sides thereof. The side member 2 is inserted into the recess 4a. ing. Front steps 8, 8 are joined to both ends of the floor cross member 4, and a rocker inner 9 forming a lower edge of a front door opening is joined to an outer edge of the step 8, and a rear door opening is formed on the rocker inner 9. A floor side rail 10 forming a lower edge is connected via a connecting member 11.

The left and right side members 2 each have a hat-shaped cross section that opens upward. A plate-shaped upper plate 15 is joined to the upper surface of the hat member, thereby forming a rectangular closed cross section. I have. Further, a reinforcing plate 16 for increasing the proof stress is inserted in each side member 2.

A resin bumper cover 14 extending in the vehicle width direction is disposed in front of the left and right side members 2. A hood lock support 19, which is a radiator support for supporting the condenser 17 and the radiator 18, is connected to the center of the front cross member 3 in the vehicle width direction (see FIG. 2).

The front end surfaces of the left and right side members 2 are joined by a bumper reinforcement 20 extending in the vehicle width direction. The bumper reinforcement 20 is made of a high-strength steel plate, and is composed of an outer reinforcement 21 having a substantially hat-shaped cross section that opens rearward, and an inner reinforcement 22 having a strip shape. .

An outer flange 21a is formed on an outer peripheral edge of the outer reinforcement 21, and an inner flange 22a is formed on an outer peripheral edge of the inner reinforcement 22, and the two flanges 21a, 22a are joined. Form a closed cross section. The inner reinforcement 22 has a protruding portion 22b protruding in the longitudinal direction, thereby improving the strength against bending and torsion.

Both ends of the bumper reinforcement 20 are fastened and fixed to the front flange 2c of the side member 2 by bolts 24 with a reinforcing plate 23 interposed therebetween, and the lower center portion is fixed to the front cross member 3 by bolts 24. It is fastened and fixed to the bracket 25.

The outer reinforcement 21
Is the thickness t2 of the inner reinforcement 22.
It is set smaller, specifically, t1 is 0.8 to 1.0
mm, and t2 is set to 1.6 to 2.0 mm.
As a result, the pre-crash zone a for reducing the deceleration at the time of a low-speed collision by the outer reinforcement 21 and the larger impact force applied to the inner reinforcement 22 and the side member 2 are applied to the bumper reinforcement 20. And a shock absorbing zone b for absorbing shock energy (see FIG. 1).

Next, the operation and effect of this embodiment will be described. According to the present embodiment, the bumper reinforcement 2
0 is composed of the outer reinforcement 20 and the inner reinforcement 22, and the thickness t1 of the outer reinforcement 21 is smaller than the thickness t2 of the inner reinforcement 22, so that, for example, 13 km / h or less. The impact force in the event of a collision during low-speed traveling is deformed and absorbed by the outer reinforcement 21 alone, so that the deceleration at the time of a low-speed collision can be reduced, and the transmission of the collision energy to the side members 2 can be reduced. Can be suppressed. Thereby, the operation at the time of low-speed collision when the airbag system is mounted can be prevented.

When a large impact force acts, the impact force is transmitted to the left and right side members 2 via the inner reinforcement 22, whereby the side members 2 are compressed and deformed in the axial direction. As a result, the collision energy can be absorbed, the energy absorption capacity can be secured, and the influence on the vehicle compartment can be suppressed.

In this embodiment, since it is only necessary to reduce the thickness of the outer reinforcement 21, it is not necessary to take extra space as compared with the case where another member is added, and the number of parts is increased. Can be avoided. Further, since the thickness of the inner reinforcement 22 is sufficiently ensured, the bonding strength with the side member 2 can be maintained, and the original function of preventing the side member 2 from falling down can be maintained without increasing the weight. .

That is, since the bumper reinforcement 20 is connected to the front end surfaces of the left and right side members 2, as shown in FIG. 4, at the time of a so-called offset collision, an input acting on the side member 2 on the collision side. Energy can be released to the opposite side member 2 ′, and the side member 2 can be reliably prevented from falling down.

Since the floor side rail 10 is connected to the rocker inner 9 of the floor cross member 4 via the connecting member 11, the input energy acting on the rocker inner 9 from the tire T can be released to the rear, and the rocker inner 9
Prevents the front door from opening due to the deformation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a front body structure of an automobile according to an embodiment of the present invention (a cross-sectional view taken along line II of FIG. 3).

FIG. 2 is a sectional view of the front vehicle body (a sectional view taken along line II-II in FIG. 3).

FIG. 3 is an exploded perspective view of a vehicle body frame constituting the vehicle body.

FIG. 4 is a schematic plan view showing an energy transmission path of the vehicle body frame.

FIG. 5 is a cross-sectional view of a conventional general front vehicle body.

FIG. 6 is a schematic plan view of a conventional front vehicle body.

[Explanation of symbols]

 2 side member 20 bumper reinforcement 21 outer reinforcement 22 inner reinforcement t1, t2 thickness

Claims (1)

[Claims] 1. A front body structure of an automobile in which front end surfaces of left and right side members extending in a vehicle front-rear direction are connected to each other by a reinforcement extending in a vehicle width direction. A substantially hat-shaped outer reinforcement and a strip-shaped inner reinforcement have a closed cross-sectional shape, and the thickness of the outer reinforcement is smaller than the thickness of the inner reinforcement. A front body structure of an automobile, wherein the outer reinforcement reduces deceleration in a low-speed collision.