JP2004291714A - Rear floor structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear floor structure for suppressing an increase in weight and improving collision energy absorbing efficiency of a rear floor at the time of a rear end collision. <P>SOLUTION: This rear floor structure 1 is provided with a rear floor panel 2 of a vehicle body, and left and right rear frames 3 extending in a vehicle body front and rear direction to form closed section together with the rear floor panel 2. The left and right rear frames 3 are formed by members having higher strength than that of the rear floor panel 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rear floor structure corresponding to a rear collision.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been a demand for a lighter body structure of an automobile in consideration of environmental issues and the like.
On the other hand, in order to maintain and improve the occupant protection performance at the time of a vehicle collision, it is necessary to secure a certain level of vehicle body strength and vehicle body rigidity.
[0003]
Therefore, in order to ensure the strength and rigidity of necessary parts, a plurality of members having different characteristics are joined by welding or the like to form the body structure of the vehicle body.
For example, Patent Literature 1 discloses a technique for joining dissimilar materials in parallel.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-104749 ([0005]-[0007])
[0005]
[Problems to be solved by the invention]
When the collision energy of the vehicle increases at the time of a rear collision, the amount of deformation of the vehicle body increases in proportion thereto. In order to cope with a larger collision energy, it is conceivable to increase the strength of the vehicle body (increase the cross section of the rear frame, increase the plate thickness, improve the material, etc.) or increase the crush range (crash stroke) at the time of a rear collision. .
However, today, it is important to reduce the weight of an automobile body, and it is important to increase the collision energy absorption efficiency of the vehicle body without increasing the weight as much as possible.
[0006]
Therefore, an object of the present invention is to provide a rear floor structure in which an increase in weight is suppressed and the collision energy absorption efficiency of the rear floor at the time of a rear collision is improved.
[0007]
[Means for Solving the Problems]
The present invention is a rear floor structure including a rear floor panel of a vehicle body and left and right rear frames extending in the vehicle front-rear direction and forming a closed cross section together with the rear floor panel, wherein the left and right rear frames have higher strength than the rear floor panel. It is characterized by being formed of a member.
[0008]
According to such a configuration, the left and right rear frames are formed of a high-strength member such as a high-strength steel plate, and the central rear floor panel is formed of a low-strength member such as a mild steel plate. The energy absorption efficiency can be increased while keeping the amount small. In other words, by increasing the buckling load of the left and right rear frames, it becomes possible to protect the cabin by reducing the amount of vehicle deformation even with a larger collision energy, while deformation exceeding the buckling load When this happens, the left and right rear frames are crushed together with the central rear floor panel, so that it is possible to improve the impact absorption efficiency at the time of a rear collision.
[0009]
Further, the above-described rear floor structure is characterized in that curved portions are provided on the left and right rear frames so that buckling occurs at a specific location, and these curved portions are joined by a cross member.
[0010]
According to such a configuration, for example, the curved portion of the rear frame is located between the cabin and the trunk, and the rear frame buckles at the curved portion in the event of a rear collision. Then, the crush deformation due to the collision energy is performed only by the trunk located behind the cross member, and the crush deformation on the passenger side can be prevented by the high strength cross member.
Therefore, while the deformation of the passenger compartment is minimized, the collision energy is absorbed by the crush deformation of the trunk, and the impact applied to the occupant can be reduced.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
FIG. 1 is a perspective view showing a rear floor structure according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II of FIG.
[0013]
A rear floor structure 1 shown in FIGS. 1 and 2 includes a rear floor panel 2 and left and right rear frames 3 and constitutes a part of a monocoque body of a passenger car.
When manufacturing the rear floor structure 1, high strength steel plates are butt-welded to both ends of a mild steel plate and then welded, followed by press working to form the rear floor panel 2 and the left and right rear frame upper surface portions 3A. Then, the rear floor panel 2 and the left and right rear frames 3 are integrated by butt-welding the rear frame lower portion 3B made of a high-strength member having a U-shaped cross section to the rear frame upper surface portion 3A. Then, the cross member 4 is welded to the rear floor structure 1 over the vehicle width direction.
[0014]
In such a rear floor structure 1, a high strength left and right rear frame 3 is joined to both ends of a low strength rear floor panel 2.
In addition, as a high-strength steel plate, a material called Hi-Ten is used.
[0015]
As shown in FIG. 1, the rear floor structure 1 is divided into a passenger compartment side and a trunk side by a cross member 4, and a rear seat is disposed in front of the cross member 4 (in the passenger compartment).
[0016]
Next, a modification of the rear floor structure 1 at the time of a rear collision will be described with reference to FIG. FIGS. 3A and 3B are explanatory diagrams illustrating a state in which the rear frame 3 is deformed beyond the buckling load due to a rear collision. FIG. 3A is a model diagram illustrating a state in which a collision force is transmitted to the rear frame 3, and FIG. FIG. 4 is a model diagram showing a state in which buckling occurs in a rear frame 3.
As shown in the figure, when a rear collision occurs, buckling occurs in the rear frame 3 and the vehicle body is crushed. However, by increasing the buckling load by increasing the strength of the rear frame 3, it is possible to reduce the amount of deformation of the vehicle body at the beginning of the collision as compared with the conventional rear floor structure.
Then, when a deformation exceeding the buckling load occurs in the rear frame 3, the rear frame 3 starts to crush and deform together with the rear floor panel 2. At this time, the rear floor panel 2 formed of a mild steel plate increases the crash stroke and increases the amount of collision energy absorption.
[0017]
As shown in FIG. 3, the rear frame 3 has a curved shape at a portion where the rear seat is arranged, and the cross member 4 is fixed to the curved portion 3C. Therefore, when a collision force exceeding the buckling load is input, buckling occurs in the curved portion 3 </ b> C of the rear frame 3.
After the buckling of the rear frame 3 occurs, the rear floor structure 1 is crushed and deformed on the trunk side. However, since the collision energy is absorbed by the rear floor panel 2 formed of a mild steel plate, it is possible to prevent a strong impact from being applied to the occupant of the rear seat.
In addition, by arranging the high strength cross member 4 at the rear end of the cabin, it is possible to prevent the cabin from being crushed even when the collision force at the time of a rear collision is transmitted to the cross member 4.
[0018]
In the rear floor structure 1 described above, since the left and right rear frames 3 are formed of high-strength steel plates, the strength of the vehicle body can be increased without substantially increasing the cross section, plate thickness, and weight of the rear frames 3. ing. On the other hand, since the central rear floor panel 2 is formed of a mild steel plate, the weight of the vehicle body is also reduced.
In addition, since curved portions 3C are provided on the left and right rear frames 3 so as to cause buckling at specific locations, and these curved portions 3C are joined by the cross member 4, the safety of the occupant during a rear collision is ensured. In addition, you can control the deformation of the body.
[0019]
As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and may be variously modified or changed within the scope of the invention described in the claims. it can.
For example, as long as buckling can be caused at a specific portion of the rear frame 3, not only the curved portion 3C but also an inclined portion, a reduced cross-section portion, and other structurally vulnerable portions can be provided.
[0020]
【The invention's effect】
As described above, according to the first aspect of the present invention, the left and right rear frames are formed of high-strength members, and the central rear floor panel is formed of low-strength members. The energy absorption efficiency can be increased while keeping the amount of deformation small. In other words, by increasing the buckling load of the left and right rear frames, it becomes possible to protect the cabin by reducing the amount of vehicle deformation even with a larger collision energy, while deformation exceeding the buckling load When this happens, the left and right rear frames are crushed together with the central rear floor panel, so that it is possible to improve the impact absorption efficiency at the time of a rear collision.
[0021]
According to the invention according to claim 2, for example, the curved portion of the rear frame is located between the cabin and the trunk, and the rear frame buckles at the curved portion in the event of a rear collision. Then, the crush deformation due to the collision energy can be performed only by the trunk located behind the cross member.
Therefore, while the deformation of the passenger compartment is minimized, the collision energy is absorbed by the crush deformation of the trunk, and the impact applied to the occupant can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a rear floor structure according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line II of FIG.
3A and 3B are explanatory diagrams illustrating a state in which a rear frame is deformed by exceeding a buckling load due to a rear collision; FIG. 3A is a model diagram illustrating a state in which a collision force is transmitted to the rear frame; FIG. FIG. 4 is a model diagram showing a state in which buckling occurs.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rear floor structure 2 Rear floor panel 3 Rear frame 3C Curved part 4 Cross member

Claims (2)

A rear floor structure including a rear floor panel of a vehicle body and left and right rear frames extending in a vehicle front-rear direction and forming a closed cross section together with the rear floor panel,
A rear floor structure, wherein the left and right rear frames are formed of members having higher strength than the rear floor panel. The rear floor structure according to claim 1, wherein curved portions are provided in the left and right rear frames so as to cause buckling at specific locations, and the curved portions are joined by a cross member.

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