Rear body structure

Abstract

To provide a rear body structure that can effectively absorb collision loads and improve the functionality of the sub-trunk. [Solution] The rear structure of the vehicle body comprises a pair of left and right rear side frames 7 extending in the longitudinal direction of the vehicle body 2, a rear floor pan 8 provided between the rear side frames 7 and forming a recessed sub-trunk 20 at the bottom of the vehicle body 2, a first bending point 15 provided on the upper part of the rear side frames 7 and bending the rear side frames 7 due to collision load, a second bending point 16 provided on the lower part of the rear side frames 7 forward of the first bending point 15 and bending the rear side frames 7 due to collision load, and a first bead 21 formed in the rear floor pan 8 at a longitudinal position of the vehicle body 2 corresponding to the first bending point 15 and extending the floor portion of the sub-trunk 20 in the vehicle width direction of the vehicle body 2.

Description

Technical Field

[0001] The present invention relates to a rear body structure having a sub-trunk between rear side frames.

Background Art

[0002] Conventionally, in vehicles such as automobiles, many rear body structures for absorbing a collision load during a rear collision have been proposed. For example, Patent Document 1 discloses a rear body structure including a first weak portion provided at an upper portion of a rear side member (rear side frame) and a second weak portion provided at a lower portion of the rear side member and provided in front of the first weak portion. In such a technique, the left and right rear side frames absorb a collision load by bending starting from the first weak portion and the second weak portion during a rear collision.

[0003] By the way, in vehicles such as automobiles, generally, a sub-trunk is formed by a rear floor pan between the left and right rear side frames. Such a sub-trunk can accommodate a jack or the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] ]] However, during a rear collision of a vehicle, when the rear side frame bends, the rear floor pan also deforms. If the sub-trunk is crushed due to the deformation of the rear floor pan, there is a risk that a rigid body such as a jack stored in the sub-trunk may be pushed out under the floor in front of the vehicle body.

[0006] Furthermore, in particular, in vehicles such as hybrid and electric vehicles, there is a risk that electrical components such as motors and batteries mounted under the floor in front of the sub-trunk may be damaged by rigid bodies pushed out from the sub-trunk.

[0007] The present invention aims to provide a rear vehicle structure that can accurately absorb collision loads and improve the functionality of the sub-trunk. [Means for solving the problem]

[0008] A rear body structure according to one aspect of the present invention comprises, at the rear of the vehicle body, a pair of left and right rear side frames extending in the longitudinal direction of the vehicle body; a rear floor pan provided between the rear side frames and forming a recessed sub-trunk at the bottom of the vehicle body; a first bending point provided on the upper part of the rear side frames and bending the rear side frames due to a collision load from the rear of the vehicle body; a second bending point provided on the lower part of the rear side frames forward of the first bending point and bending the rear side frames due to the collision load; and a first bead formed in the rear floor pan at a longitudinal position of the vehicle body corresponding to the first bending point, with the floor portion of the sub-trunk extending in the vehicle width direction of the vehicle body. [Effects of the Invention]

[0009] According to the rear body structure of the present invention, collision loads can be accurately absorbed, and the functionality of the sub-trunk can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] Plan view of the rear of the vehicle, seen from above. [Figure 2] Side view of the rear of the vehicle, seen from the left side. [Figure 3] Rear side frame viewed from the left side. [Figure 4] Rear floor pan, viewed from the left side. [Figure 5]Side view of the rear of the vehicle, seen from the left side, during the initial stages of a rear-end collision. [Figure 6] Side view of the rear of the vehicle from the left side during the later stages of a rear-end collision. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the drawings. The drawings relate to one embodiment of the present invention, where Figure 1 is a plan view of the rear of the vehicle as seen from above the vehicle, and Figure 2 is a side view of the rear of the vehicle as seen from the left side.

[0012] The vehicle 1 shown in Figures 1 and 2 is, for example, an electric vehicle. The body 2 of this vehicle 1 comprises a pair of left and right side sills 5, a center floor pan 6, a pair of left and right rear side frames 7, and a rear floor pan 8.

[0013] The left and right side sills 5 have, for example, a rectangular hollow cross-sectional shape. Each side sill 5 extends in the longitudinal direction of the vehicle body 2 on both the left and right sides of the vehicle body 2. A kick-up frame 9 is connected to the rear end of each side sill 5.

[0014] The center floor pan 6 is located between the left and right side sills 5 and the left and right kick-up frames 9. The left and right sides of the center floor pan 6 are connected to the left and right side sills 5 and the left and right kick-up frames 9 by welding or other means. In this way, the center floor pan 6 forms the floor of the cabin of the vehicle body 2. Below the center floor pan 6, beneath the cabin floor, a battery housing chamber 10 is formed. This battery housing chamber 10 houses multiple battery cells (not shown).

[0015] The left and right rear side frames 7 have, for example, a rectangular hollow cross-sectional shape. These rear side frames 7 extend in the longitudinal direction of the vehicle body 2 at the rear of the vehicle body 2.

[0016] The front end of each rear side frame 7 is connected to each side sill 5 via each kick-up frame 9. Also, the rear ends of the left and right rear side frames 7 are connected by a rear bumper beam 11.

[0017] Each rear side frame 7 is provided with a first bending starting point 15 and a second bending starting point 16, respectively. The first bending starting point 15 and the second bending starting point 16 are starting points for bending the rear side frame 7 when a collision load is input from the rear of the vehicle body 2.

[0018] The first bending starting point 15 is provided, for example, at a position a distance D1 forward from the rear end of the rear side frame 7, on the upper part of the rear side frame 7 (see FIG. 3). This first bending starting point 15 is constituted by a bead extending in the vehicle width direction on the rear side frame 7. The bead constituting the first bending starting point 15 is formed, for example, by a drawing process that projects a part of the upper wall of the rear side frame 7 downward.

[0019] Such a first bending starting point 15 forms a vulnerable part with respect to the load in the front-rear direction of the vehicle body 2 on the upper part of the rear side frame 7. Thereby, when a collision load is input from the rear of the vehicle body 2, the first bending starting point 15 can bend a part of the rear side frame 7 behind the first bending starting point 15 of the rear side frame 7 upward.

[0020] The second bending starting point 16 is provided, for example, at a position a distance D2 forward from the first bending starting point 15, on the lower part of the rear side frame 7. This second bending starting point 16 is constituted by a bead extending in the vehicle width direction on the rear side frame 7. The bead constituting the second bending starting point 16 is formed, for example, by a drawing process that projects a part of the lower wall of the rear side frame 7 upward.

[0021] Such a second bending starting point 16 forms a vulnerable part against the longitudinal load of the vehicle body 2 at the lower part of the rear side frame 7. Thereby, when a collision load is input from the rear of the vehicle body 2, the second bending starting point 16 can bend a part behind the second bending starting point 16 of the rear side frame 7 downward.

[0022] Here, it is preferable that the distance D1 and the distance D2 are set to be substantially equal. More specifically, it is preferable that the distance D1 is set in the range of 95% to 105% of the distance D2.

[0023] The rear floor pan 8 is provided between the left and right rear side frames 7. The left and right side portions of the rear floor pan 8 are connected to the left and right rear side frames 7 by welding or the like. Thereby, the rear floor pan 8 forms the floor part of the luggage compartment of the vehicle body 2.

[0024] In the region on the rear side of this rear floor pan 8, a recess recessed downward of the vehicle body 2 is formed. This recess forms a sub-trunk (luggage room under box) 20 in the luggage compartment of the vehicle body 2.

[0025] Further, the rear floor pan 8 is provided with a first bead 21 extending in the vehicle width direction at the floor part of the sub-trunk 20. The first bead 21 is provided at the longitudinal position of the vehicle body 2 corresponding to the first bending starting point 15 of the rear side frame 7. Further, it is preferable that the first bead 21 is provided substantially at the center in the longitudinal direction of the vehicle body 2 at the floor part of the sub-trunk 20. In FIG. 1, a configuration in which the first bead 21 and the first bending starting point 15 are aligned in the longitudinal direction of the vehicle body 2 is illustrated, but the present invention is not limited to such a configuration. For example, the first bead 21 and the first bending starting point 15 can be arranged in the vicinity within a predetermined distance in the longitudinal direction of the vehicle body 2.

[0026] The first bead 21 has a shape that protrudes downward from the rear floor pan 8 on the floor of the sub-trunk 20. Therefore, when viewed from the inside of the sub-trunk 20, the first bead 21 has a groove shape. Such a first bead 21 is formed, for example, by drawing a portion of the rear floor pan 8 on the floor of the sub-trunk 20 so that it protrudes downward.

[0027] Furthermore, in the floor portion of the sub-trunk 20, a drain hole 22 is provided midway through the first bead 21, which penetrates the rear floor pan 8.

[0028] Here, the first bead 21 extends to the side wall portion of the sub-trunk 20. On the side wall portion of the sub-trunk 20, the first bead 21 extends in the vertical direction of the vehicle body 2. As a result, the first bead 21 extends to the vicinity of the first bending point 15.

[0029] In this embodiment, in addition to the first bead 21, the side wall portion of the sub-trunk 20 is provided with a plurality of beads 23 that extend in the vertical direction of the vehicle body 2.

[0030] Furthermore, the rear floor pan 8 is provided with a plurality of second beads 25 that extend in the longitudinal direction of the vehicle body 2 along the floor of the sub-trunk 20. Each second bead 25 has a shape that protrudes downward from the floor of the sub-trunk 20. Therefore, each second bead 25, when viewed from the inside of the sub-trunk 20, has a groove shape. These second beads 25 are formed, for example, by drawing a portion of the rear floor pan 8 in the floor of the sub-trunk 20 so that it protrudes downward.

[0031] Here, for example, as shown in Figure 1, the middle of each second bead 25 intersects with the first bead 21.

[0032] As a result, in the floor portion of the subtrunk 20, the grooves formed by the first bead 21 and the grooves formed by each of the second beads 25 are connected to each other.

[0033] Furthermore, due to the intersection of the first bead 21, a portion of each second bead 25 is more vulnerable to longitudinal loads on the vehicle body 2 compared to other parts.

[0034] A motor 30 for driving the rear wheels is positioned at the front of the sub-trunk 20 configured in this way. Furthermore, high-voltage components (not shown) for supplying power from the battery to the motor 30 are arranged around the motor 30.

[0035] According to this embodiment, the rear structure of the vehicle body includes, at the rear of the vehicle body 2, a pair of left and right rear side frames 7 extending in the longitudinal direction of the vehicle body 2, a rear floor pan 8 provided between the rear side frames 7 and forming a sub-trunk 20 that is recessed downwards from the vehicle body 2, a first bending point 15 provided on the upper part of the rear side frames 7 that bends the rear side frames 7 due to a collision load from the rear of the vehicle body 2, a second bending point 16 provided on the lower part of the rear side frames 7 forward of the first bending point 15 and that bends the rear side frames 7 due to a collision load, and a first bead 21 formed in the rear floor pan 8 at a longitudinal position of the vehicle body 2 corresponding to the first bending point 15, and extending the floor portion of the sub-trunk 20 in the vehicle width direction of the vehicle body 2. This makes it possible to accurately absorb collision loads and improve the functionality of the sub-trunk 20.

[0036] In other words, when a barrier collision occurs against the rear of the vehicle body 2, a collision load is input to each rear side frame 7 via the rear bumper beam 11. If this collision load exceeds a predetermined value, each rear side frame 7 begins to bend. As shown in Figure 5, the bending direction of the rear side frame 7 is clearly defined by a first bending point 15 located at the top of the rear side frame 7 and a second bending point 16 located at the bottom of the rear side frame 7. Therefore, even when the collision mode of the barrier 100 is different, the bending direction of the rear side frame 7 is controlled with high robustness. As a result, the collision load during a rear collision can be accurately absorbed by the rear side frame 7.

[0037] In this case, the distance D1 from the rear end of the rear side frame 7 to the first bending point 15 is set to be approximately equal to the distance D2 from the first bending point 15 to the second bending point 16. Therefore, approximately equal bending moments can be generated in the rear side frame 7 at the first bending point 15 and the second bending point 16. This allows for the generation of large bending moments at the first bending point 15 and the second bending point 16, thereby increasing the efficiency of shock load absorption by bending of the rear side frame 7.

[0038] Furthermore, the rear floor pan 8 has a first bead 21 that extends in the vehicle width direction along the floor of the sub-trunk 20 at the front-rear position of the vehicle body 2 corresponding to the first bending starting point 15. This first bead 21, in conjunction with the bending of the rear side frame 7, bends the floor of the sub-trunk 20 into a V-shape (see Figure 5). This bending creates two slopes, one in the front and one in the rear, on the floor of the sub-trunk 20. For example, as shown in Figure 6, as the bending of the floor progresses, the luggage 101 loaded in the sub-trunk 20 is pushed upward by the two slopes. Specifically, the luggage 101 is pushed forward by the rear slope of the floor and slides upward along the front slope of the floor. This prevents the luggage 101 from breaking through the front wall of the sub-trunk 20 and moving forward of the vehicle body 2 even if the sub-trunk 20 is crushed by a collision load. Therefore, even when the luggage 101 loaded in the sub-trunk 20 is a rigid body, the function of protecting electrical components such as the motor 30 from the luggage 101 during a rear collision can be improved.

[0039] Furthermore, the first bead 21 formed on the floor of the sub-trunk 20 is shaped to protrude downwards from the rear floor pan 8. In addition, a drain hole 22 is provided in the middle of the first bead 21, which penetrates the rear floor pan 8. With these configurations, water that enters the sub-trunk 20 is collected in the groove formed by the first bead 21 and then discharged through the drain hole 22. Thus, the drainage function of the sub-trunk 20 can be improved.

[0040] In this case, a second bead 25 extending in the longitudinal direction of the vehicle body 2 is provided on the floor of the sub-trunk 20, and the first bead 21 intersects the second bead 25 midway. This allows water in the sub-trunk 20 to be collected more efficiently and discharged through the drain hole 22.

[0041] The inventions described in the above embodiments are not limited to those forms, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed.

[0042] For example, if the problem described can be solved and the effects described can be obtained even if some of the constituent elements shown in the above form are removed, then the configuration with the removed constituent elements can be extracted as an invention. [Explanation of symbols]

[0043] 1 ... Vehicle 2… Vehicle body 5… Side sill 6… Center floor pan 7… Rear side frame 8… Rear floor pan 9… Kick-up frame 10… Battery storage room 11… Rear bumper beam 15 … First bending point 16 … Second bending point 20… Subtrunk 21... First bead 22 … Drain hole 23… Bead 25... Second bead 30… Motor 100 ... Barrier 101... Luggage D1… Distance D2 … distance

Claims

1. At the rear of the vehicle body, a pair of left and right rear side frames extending in the longitudinal direction of the vehicle body, A rear floor pan is provided between the rear side frames and forms a recessed sub-trunk at the bottom of the vehicle body, A first bending point is provided on the upper part of the rear side frame, which bends the rear side frame due to a collision load from the rear of the vehicle body, A second bending point is provided on the lower part of the rear side frame, forward of the first bending point, which causes the rear side frame to bend due to the collision load, A first bead is formed in the rear floor pan at a longitudinal position of the vehicle body corresponding to the first bending point, and the floor portion of the sub-trunk extends in the vehicle width direction of the vehicle body, A rear body structure characterized by having the following features.

2. The rear body structure of the vehicle according to claim 1, characterized in that the distance from the rear end of the rear side frame to the first bending point is set in the range of 95% to 105% of the distance from the first bending point to the second bending point.

3. The first bead has a shape that protrudes below the rear floor pan in the floor portion, The rear body structure according to claim 1, characterized in that the rear floor pan has a drainage hole that penetrates the rear floor pan in the middle of the first bead.

4. The rear floor pan is provided with a second bead that extends in the longitudinal direction of the vehicle body in the floor portion of the sub-trunk, The rear body structure of the vehicle according to claim 1, characterized in that the middle of the second bead intersects with the first bead.

5. The rear body structure of the vehicle according to claim 1, characterized in that the first bead extends further in the vertical direction of the vehicle body at the left and right side walls of the sub-trunk.

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