JP4394894B2 - Rear floor structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rear floor structure corresponding to a rear collision.
[0002]
[Prior art]
In recent years, there has been a demand for lighter body structures of automobiles in consideration of environmental problems.
On the other hand, in order to maintain and improve the occupant protection performance in the event of a vehicle collision, it is necessary to ensure a certain level of vehicle body strength and vehicle body rigidity.
[0003]
Therefore, in order to ensure the strength and rigidity of necessary portions, a plurality of members having different characteristics are joined together by welding or the like to form the body structure of the vehicle body.
For example, Patent Document 1 discloses a technique for joining dissimilar materials in parallel.
[0004]
[Patent Document 1]
JP-A-11-104749 ([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 deformation amount of the vehicle body also increases in proportion thereto. In order to deal with a larger collision energy, it is possible to increase the strength of the vehicle body (rear frame cross section, increase in plate thickness, material improvement, etc.) and increase the crush range (crash stroke) at the time of rear collision. .
However, nowadays, where the weight reduction of the automobile body is required, it is important to increase the collision energy absorption efficiency of the vehicle body without increasing the weight as much as possible.
[0006]
Accordingly, an object of the present invention is to provide a rear floor structure that suppresses an increase in weight and improves the collision energy absorption efficiency of the rear floor at the time of a rear collision.
[0007]
[Means for Solving the Problems]
The present invention is a rear floor structure comprising a rear floor panel of a vehicle body and left and right rear frames extending in the longitudinal direction of the vehicle body and forming a closed section together with the rear floor panel , wherein the rear floor panel is formed of mild steel plate, The rear frame is made of a high strength material that is stronger than the mild steel plate , and in order to cause buckling at a specific location, a curved portion is provided in a portion between the cabin and the trunk of the left and right rear frames. The section is joined by a cross member that separates the cabin side and the trunk side.
[0008]
According to such a configuration, the left and right rear frames are formed of high-strength members such as high-strength steel plates, and the center rear floor panel is formed of low-strength members such as mild steel plates. 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 is possible to protect the passenger cabin by reducing the amount of vehicle body deformation even for larger collision energy, while deformation exceeding the buckling load occurs. When it happens, the left and right rear frames are crushed together with the central rear floor panel, so that the impact absorption efficiency at the time of rear collision can be improved.
Further, according to such a configuration, for example, the curved portion of the rear frame is positioned between the cabin and the trunk, and the rear frame is buckled at the curved portion at the time of a rear collision. Then, the deformation due to the collision energy can be performed only by the trunk located behind the cross member, and the deformation on the cabin side can be prevented by the cross member having high strength.
Therefore, while the deformation of the passenger cabin is minimized, the collision energy is absorbed by the collapsed deformation of the trunk, and the impact applied to the occupant can be mitigated.
[0009]
Further, in the above-described rear floor structure, the rear frame has a rear frame upper surface portion made of a high strength material butt welded to both right and left ends of the rear floor panel, and a cross section welded to the rear frame upper surface portion to form a closed cross section. And a rear frame lower portion made of a U-shaped high-tensile material .
[0010]
According to such a configuration, for example, the curved portion of the rear frame is positioned between the cabin and the trunk, and the rear frame is buckled at the curved portion at the time of a rear collision. Then, the deformation due to the collision energy can be performed only by the trunk located behind the cross member, and the deformation on the cabin side can be prevented by the cross member having high strength.
Therefore, while the deformation of the passenger cabin is minimized, the collision energy is absorbed by the collapsed deformation of the trunk, and the impact applied to the occupant can be mitigated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below 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 the 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 the rear floor structure 1 is manufactured, a high-strength steel plate is abutted and welded to both ends of the mild steel plate, and then press working is performed to form the rear floor panel 2 and the left and right rear frame upper surface portions 3A. Thereafter, the rear frame lower panel 3B made of a high-strength member having a U-shaped cross section is butt welded to the rear frame upper surface portion 3A, so that the rear floor panel 2 and the left and right rear frames 3 are integrated. And the cross member 4 is welded to the rear floor structure 1 over the vehicle width direction.
[0014]
Such a rear floor structure 1 has a configuration in which left and right rear frames 3 having high strength are joined to both ends of a rear floor panel 2 having low strength.
In addition, as a high strength steel plate, a material called “HITEN” is used.
[0015]
As shown in FIG. 1, the rear floor structure 1 is divided into a cabin side and a trunk side by a cross member 4, and a rear seat is arranged in front of the cross member 4 (a cabin side).
[0016]
Next, with reference to FIG. 3, the deformation | transformation of the rear floor structure 1 at the time of a rear surface collision is demonstrated. FIG. 3 is an explanatory view showing a state in which the rear frame 3 is deformed by exceeding a buckling load due to a rear collision. FIG. 3A is a model diagram showing a state in which a collision force is transmitted to the rear frame 3. FIG. 4 is a model diagram showing a state in which buckling occurs in the rear frame 3. FIG.
As shown in the figure, when a rear collision occurs, the rear frame 3 is buckled and the vehicle body is crushed. However, since the rear frame 3 has high strength and the buckling load is increased, the deformation amount of the vehicle body at the initial stage of the collision can be reduced as compared with the conventional rear floor structure.
When the rear frame 3 undergoes deformation exceeding the buckling load, the rear frame 3 starts to be crushed and deformed together with the rear floor panel 2. At that time, the rear floor panel 2 formed of a mild steel plate increases the crash stroke and increases the amount of collision energy absorbed.
[0017]
As shown in FIG. 3, the rear frame 3 has a curved shape at a portion where the rear seat is disposed, and the cross member 4 is fixed to the curved portion 3 </ b> C. 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 passenger compartment, it is possible to prevent the passenger compartment from being crushed even when a 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, the left and right rear frames 3 are formed of high-strength steel plates, thereby increasing the strength of the vehicle body without substantially increasing the cross-section, plate thickness, and weight of the rear frame 3. ing. On the other hand, since the central rear floor panel 2 is formed of a mild steel plate, the weight of the automobile body is also reduced.
Further, in order to cause buckling at a specific location, the left and right rear frames 3 are provided with curved portions 3C, and these curved portions 3C are joined by the cross member 4, so that the safety of the occupant is ensured at the time of a rear collision. In addition, you can control the deformation of the car body.
[0019]
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the invention described in the claims. it can.
For example, as long as buckling can occur at a specific location on the rear frame 3, it is not limited to the curved portion 3C, and an inclined portion, a cross-sectional reduced portion, and other structurally fragile portions can also 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. Energy absorption efficiency can be increased while keeping the deformation amount small. In other words, by increasing the buckling load of the left and right rear frames, it is possible to protect the passenger cabin by reducing the amount of vehicle body deformation even for larger collision energy, while deformation exceeding the buckling load occurs. When it happens, the left and right rear frames are crushed together with the central rear floor panel, so that the impact absorption efficiency at the time of rear collision can be improved.
[0021]
According to the second aspect of the invention, for example, the curved portion of the rear frame is positioned between the cabin and the trunk, and the rear frame is buckled at the curved portion at the time of a rear collision. Then, the crushing 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 cabin is minimized, the collision energy is absorbed by the collapsed deformation of the trunk, and the impact applied to the occupant can be mitigated.
[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 cross-sectional view taken along the line II of FIG.
FIGS. 3A and 3B are explanatory views showing a state in which the rear frame is deformed exceeding a buckling load due to a rear collision, FIG. 3A is a model diagram showing a state in which a collision force is transmitted to the rear frame, and FIG. It is a model figure which shows the state which buckle arises in.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rear floor structure 2 Rear floor panel 3 Rear frame 3C Bending part 4 Cross member

Claims (2)

A rear floor structure comprising a rear floor panel of a vehicle body and left and right rear frames that extend in the longitudinal direction of the vehicle body and form a closed section together with the rear floor panel,
The rear floor panel is formed of a mild steel plate, the left and right rear frames are formed of a high-tensile material having a higher strength than the mild steel plate, and a cabin and a trunk of the left and right rear frames are formed so as to buckle at a specific location. Provide a curved part in the part between
A rear floor structure characterized in that these curved portions are joined by a cross member that separates the cabin side and the trunk side. The rear frame includes a rear frame upper surface portion made of a high-tensile material butt welded to both right and left ends of the rear floor panel, and a rear portion made of a high-tensile material having a U-shaped cross section that is welded to the rear frame upper surface portion to form a closed cross section. The rear floor structure according to claim 1, further comprising a frame lower part .

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