JP2021142763A - Body structure of automobile - Google Patents

Abstract

To provide a body rear part structure of the automobile with a rear frame extending backward from a rear end of a side sill which can improve absorption effect of collision energy at the time of a rear end collision.SOLUTION: A rear frame 12 is constituted to be a closed cross section by connecting an inner component 25 having an approximately U-shaped cross section opening to outside in a vehicle width direction with an outer component 26 blocking the opening part of the inner component 25, and the rear frame 12 is connected with a cross member 16 by a reinforcement member 17 having an L-shaped cross section to be a triangular box structure 28 in a plane view, so that in addition to expansion of a cross-section area of the rear frame 12, collision load of the rear end collision can be efficiently dispersed from the rear frame 12 to both of the side sill 11 and the cross member 16. In particular, the triangular box structure 28 in a plane view is connected to the cross member 16 in a wide range in a vehicle width direction so as to improve load dispersion effect regarding the cross member 16.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle body structure including a pair of left and right rear frames extending rearward from a pair of left and right side sills and a cross member extending in the vehicle width direction and connecting between the left and right rear frames.

A pair of left and right rear frames arranged in the front-rear direction at the rear of the vehicle body of an automobile are connected to the lower surface of the rear floor panel to form a closed cross section, and therefore generally have a hat-shaped cross section that opens upward.

On the other hand, in Patent Document 1 below, the rear portion of the rear frame is configured to have a U-shaped cross section that opens outward in the vehicle width direction, and the rear portion of the side sill inner that opens outward in the vehicle width direction is inside the vehicle width direction. It is described that the rear frame suppresses the rotation of the side sill at the time of a side collision by fitting and connecting from the side.

Japanese Patent No. 3518397

However, in the above-mentioned conventional one, not only the weight increases because the rear part of the side sill and the front part of the rear frame need to be overlapped over a predetermined distance, but also the collision energy at the rear part of the rear frame in the event of a rear surface collision. It may not be possible to protect the articles mounted between the left and right rear frames because it cannot absorb the energy efficiently.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enhance the effect of absorbing collision energy at the time of a rear surface collision in the rear body structure of an automobile provided with a rear frame extending rearward from the rear end of the side sill.

In order to achieve the above object, according to the invention of claim 1, between the pair of left and right rear frames extending rearward from the rear end of the pair of left and right side sills and the left and right rear frames extending in the vehicle width direction. The rear frame is an inner member having a substantially U-shaped cross section that opens outward in the vehicle width direction, and an outer member that closes the opening of the inner member. The rear frame and the cross member are connected by a reinforcing member having an L-shaped cross section to form a triangular box structure in a plan view. A car body structure is proposed.

Further, according to the invention described in claim 2, in addition to the configuration of claim 1, the rear frame has an inclined portion that inclines inward in the vehicle width direction toward the rear and a rear end to the rear of the inclined portion. The lower edge of the inner member of the rear frame is connected to the lower edge of the outer member of the rear frame by a joining flange extending downward at the inclined portion, which is composed of a horizontal portion extending substantially horizontally toward the rear frame. A vehicle body structure is proposed, characterized in that it is connected to the lower edge of the outer member of the rear frame by a joining flange extending outward in the vehicle width direction.

Further, according to the third aspect of the present invention, in addition to the configuration of the first aspect, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the outer of the rear frame. A vehicle body structure of an automobile is proposed, wherein the member includes a bead extending in the front-rear direction along a middle portion in the vertical direction about the bent portion.

Further, according to the invention described in claim 4, in addition to the configuration of claim 1, the rear portion of the side sill is provided with a first widening portion that widens inward in the vehicle width direction, and is in front of the inclined portion of the rear frame. The portion includes a second widening portion that widens outward in the vehicle width direction, and the rear end of the first widening portion and the front end of the second widening portion are connected by a joining flange that protrudes in a direction orthogonal to the front-rear direction. A vehicle body structure is proposed in which the inner wall in the vehicle width direction of the first widening portion and the inner wall in the vehicle width direction of the inclined portion are continuous in a straight line in a plan view.

According to the invention of claim 5, in addition to the configuration of claim 1, the rear frame is made of a hot stamping material, and the side sill is made of a high-tensile material. Is proposed.

According to the invention of claim 6, in addition to the configuration of claim 1, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the bent portion is a damper. An automobile body structure is proposed, which comprises connecting to a rear pillar via a housing and an upper gusset.

According to the invention described in claim 7, in addition to the configuration of claim 1, the ridgeline of the reinforcing member includes a bent portion at the boundary between the inclined portion and the horizontal portion of the rear frame and the rear portion of the cross member. A vehicle body structure characterized by connecting to the ridgeline of the vehicle is proposed.

According to the invention of claim 8, in addition to the configuration of claim 1, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the bent portion is a damper. An automobile body structure characterized by being connected to a housing is proposed.

According to the invention of claim 9, in addition to the configuration of claim 8, the upper part of the damper housing is inclined inward in the vehicle width direction, and the axis of the damper housed in the damper housing is upward. It is proposed that the body structure of an automobile that is inclined rearward and that the damper base of the damper housing is connected to the rear pillar via the upper gusset and is connected to the bent portion of the rear frame via the lower gusset.

According to the invention of claim 10, in addition to the configuration of claim 1, a battery box mounted below the floor panel in front of the connection portion between the left and right rear frames and the left and right side sills. The cross member and the cross member of the floor panel are arranged between the left and right side sills in the vehicle width direction, and behind the connection portion, the left and right rear frames are connected by the cross member provided on the rear floor panel. The body structure of an automobile, which is characterized by being used, is proposed.

The rear cross member 16 of the embodiment corresponds to a cross member connecting between the left and right rear frames of the present invention, and the battery box cross member 40 of the embodiment corresponds to the cross member of the battery box of the present invention. The floor cross member 44 of the embodiment corresponds to the cross member of the floor panel of the present invention.

According to the configuration of claim 1, the vehicle body includes a pair of left and right rear frames extending rearward from the rear ends of the pair of left and right side sills, and a cross member extending in the vehicle width direction and connected between the left and right rear frames. To be equipped.

The rear frame is configured to have a closed cross section by connecting an inner member having a substantially U-shaped cross section that opens outward in the vehicle width direction and an outer member that closes the opening of the inner member, and the rear frame and the cross member are L. Since the box structure portion having a triangular shape in a plan view is formed by connecting with a reinforcing member having a character-shaped cross section, the cross-sectional area of the rear frame is compared with the case where the rear frame is provided with a member having a substantially U-shaped cross section that opens upward. By reinforcing the connection portion between the rear frame and the cross member with a reinforcing member, the collision load of the rear surface collision can be efficiently distributed from the rear frame to both the side sill and the cross member. In particular, since the triangular box structure in a plan view is connected to the cross member in a wide range in the vehicle width direction, the load distribution effect on the cross member is enhanced.

Further, according to the configuration of claim 2, the rear frame is composed of an inclined portion that inclines inward in the vehicle width direction toward the rear and a horizontal portion that extends substantially horizontally from the rear end of the inclined portion toward the rear. The lower edge of the inner member of the rear frame is connected to the lower edge of the outer member of the rear frame by a joint flange extending downward at the inclined portion, and the lower edge of the outer member of the rear frame is connected to the lower edge of the outer member of the rear frame at the horizontal portion. When the collision load of the rear surface collision is input, the horizontal part is suppressed from deformation in the vehicle width direction by the joint flange extending outward in the vehicle width direction, and the inclined part is suppressed by the joint flange extending downward in the vehicle width direction. Deformation in the vertical direction is suppressed.

Further, according to the configuration of claim 3, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the outer member of the rear frame is centered on the bent portion along the intermediate portion in the vertical direction. Since it has a bead that extends in the front-rear direction, it is possible to increase the strength of the rear frame while minimizing the increase in weight.

Further, according to the configuration of claim 4, the rear portion of the side sill is provided with a first widening portion that widens inward in the vehicle width direction, and the front portion of the inclined portion of the rear frame is a second widening portion that widens outward in the vehicle width direction. The rear end of the first widening portion and the front end of the second widening portion are connected by a joint flange protruding in a direction orthogonal to the front-rear direction, and the inner wall in the vehicle width direction of the first widening portion and the vehicle width direction of the inclined portion are connected. Since it is linearly continuous with the inner wall in a plan view, the collision load of the rear surface collision can be efficiently transmitted and distributed from the rear frame to the side sill while connecting the side sill and the rear frame with a lightweight joining flange.

Further, according to the configuration of claim 5, since the rear frame is made of a hot stamping material and the side sill is made of a high-tensile material, it is possible to easily mold a rear frame having a complicated shape with a hot stamping material having high moldability. Not only that, the side sill to which stress is concentrated at the time of rear collision can be composed of a high-tensile steel having lower strength and higher ductility than the hot stamping material, and the collision energy can be effectively absorbed.

Further, according to the configuration of claim 6, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the bent portion is connected to the rear pillar via the damper housing and the upper gusset, so that the damper The load input from is transmitted from the damper housing to the rear pillar via the upper gusset and can be supported more reliably.

Further, according to the configuration of claim 7, since the ridgeline of the reinforcing member connects the bent portion of the boundary between the inclined portion and the horizontal portion of the rear frame and the ridgeline of the rear portion of the cross member, the collision load of the rear surface collision is rear. The stress is transmitted to the cross member via the highly rigid ridgeline without concentrating the stress on the bent portion of the frame.

Further, according to the configuration of claim 8, the rear frame is provided with a bent portion at the boundary between the inclined portion on the front side and the horizontal portion on the rear side, and the bent portion is connected to the damper housing, so that the load input from the damper is applied to the damper housing. Can be transmitted to and supported at the bent portion of the rear frame.

Further, according to the configuration of claim 9, since the upper part of the damper housing is inclined inward in the vehicle width direction, a large-diameter tire can be mounted, and the axis of the damper housed in the damper housing is inclined rearward. Therefore, the rear seat can be placed at the rear to improve the sitting posture, and the damper base of the damper housing is connected to the rear pillar via the upper gusset and is connected to the bent part of the rear frame via the lower gusset, so the damper The load input to the damper base can be distributed and supported by the bent portions of the rear pillar and the rear frame.

Further, according to the configuration of claim 10, in front of the connection portion between the left and right rear frames and the left and right side sills, the cross member of the battery box mounted below the floor panel and the cross member of the floor panel are left and right side sills. It is arranged in the vehicle width direction between them, and behind the connection part, the left and right rear frames are connected by a cross member provided on the rear floor panel, so that the collision load of the rear collision can be applied to the cross member of the rear floor panel and the floor panel. It can be supported by the cross member and the cross member of the battery box to protect the battery stored in the battery box.

It is a left side view of the rear part of the car body. It is a two-way arrow view of FIG. It is a three-part enlarged view of FIG. It is a four-direction arrow view of FIG. FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. FIG. 6 is a cross-sectional view taken along the line 6-6 of FIG. It is a cross-sectional view of line 7A-7A and line 7B-7B of FIG. 8-8 is a cross-sectional view taken along the line 8-8 of FIG. It is a 9-direction arrow view of FIG. It is explanatory drawing of the reason why the cross-sectional area of a rear frame increases.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 10. In the present specification, the front-rear direction, the left-right direction (vehicle width direction), and the up-down direction are defined with reference to the occupant seated in the driver's seat.

As shown in FIGS. 1 and 2, a pair of left and right side sills 11 are arranged in the front-rear direction on the vehicle body side of the electric vehicle, and a pair of left and right rear frames 12 extend rearward from the rear ends of the left and right side sills 11. A pair of left and right extensions 13 which are collision energy absorbing members are connected to the rear ends of the left and right rear frames 12. The rear frame 12 is composed of an inclined portion 14 on the front side and a horizontal portion 15 on the rear side. The inclined portion 14 extends inward and upward in the vehicle width direction from the rear end of the side sill 11 toward the rear, and the horizontal portion 15 is formed. The extension 13 extends straight rearward from the rear end of the inclined portion 14, and the extension 13 extends straight rearward from the rear end of the horizontal portion 15. The inclined portions 14 of the left and right rear frames 12 are connected by a rear cross member 16 extending in the vehicle width direction, and the rear side of the rear cross member 16 and the inside of the inclined portion 14 in the vehicle width direction are triangular reinforcing members in a plan view. It is connected at 17 and reinforced. The rear frame 12 is made of hot stamping material, and the side sill 11 is made of high-tensile material.

A square frame-shaped subframe 18 that supports high-voltage electric parts such as an electric motor for traveling is mounted between the left and right rear frames 12. The subframe 18 is a front cross member 20 that connects a pair of left and right side frames 19 extending in the front-rear direction along the inside of the left and right rear frames 12 in the vehicle width direction and the front ends of the left and right side frames 19 in the vehicle width direction. A pair of left and right cross members 21 that connect the rear ends of the left and right side frames 19 in the vehicle width direction, and a pair of left and right cross members 20 that extend forward and outward in the vehicle width direction from both ends in the vehicle width direction. The left and right mounting arms 22 are fastened to the lower surfaces of the inclined portions 14 of the left and right rear frames 12, and both ends of the front cross member 20 in the vehicle width direction are attached to the lower surfaces of the left and right reinforcing members 17. Both ends of the rear cross member 21 in the vehicle width direction are fastened to the lower surface of the horizontal portion 15 of the left and right rear frames 12.

As is clear from FIGS. 3 and 8, the side sill 11 includes an inner member 23 having a hat-shaped cross section that opens outward in the vehicle width direction and an outer member 24 having a hat-shaped cross section that opens inward in the vehicle width direction. They are connected by the joining flanges 23a and 24a to form a hollow closed cross section. At the rear end of the side sill 11, a first widening portion 11a (see FIG. 3) is formed in which the inner member 23 is obliquely bulged inward in the vehicle width direction.

On the other hand, as is clear from FIGS. 3, 6 and 7, the rear frame 12 is hollow by connecting the inner member 25 having a hat-shaped cross section that opens outward in the vehicle width direction and the outer member 26 having a flat cross section. It is composed of a closed cross section. On the upper surface side of the rear frame 12, the joint flange 25a of the inner member 25 and the joint flange 26a of the outer member 26 extend in the vertical direction (see FIGS. 7A and 7B), but the inclined portion of the rear frame 12 On the lower surface side of 14, the joint flange 25b of the inner member 25 and the joint flange 26b of the outer member 26 extend in the vertical direction (see FIG. 7A), whereas the lower surface side of the horizontal portion 15 of the rear frame 12 Then, the joining flange 25c of the inner member 25 and the joining flange 26c of the outer member 26 extend in the horizontal direction (see FIG. 7B). That is, on the lower surface side of the rear frame 12, the directions of the joining flanges 25b and 26b of the inclined portion 14 and the joining flanges 25c and 26c of the horizontal portion 15 are switched from the vertical direction to the horizontal direction. Reinforcing beads 25d and 26d along the longitudinal direction of the rear frame 12 are formed on the inner surface in the vehicle width direction and the outer surface in the vehicle width direction.

As is clear from FIGS. 3 and 6, a second widening portion 12a (see FIG. 3) in which the outer member 26 is bulged outward in the vehicle width direction is formed at the front end portion of the inclined portion 14 of the rear frame 12. Will be done. The first widening portion 11a of the side sill 11 and the second widening portion 12a of the rear frame 12 are connected by abutting the joining flanges 11b and 12b protruding in the vertical direction and the vehicle width direction. In this state, the inner wall in the vehicle width direction of the first widening portion 11a of the side sill 11 and the inclined portion 14 of the rear frame 12 is linearly inclined inward in the vehicle width direction toward the rear in a plan view (FIG. 3). See the thick chain line).

As is clear from FIGS. 3 and 7B, the reinforcing member 17 has a triangular horizontal wall 17a and a rectangular vertical wall 17b, and is formed in an L-shaped cross section. The joining flanges 17c and 17d along the two sides of the above are connected to the lower surface of the inclined portion 14 of the rear frame 12 and the lower surface of the rear cross member 16, and the joining flanges 17e of the vertical wall 17b are between the upper surfaces of the left and right rear frames 1. Is connected to the lower surface of the rear floor panel 27. As a result, the box structure portion 28 (see FIG. 7A) is formed between the inclined portion 14, the rear cross member 16, the reinforcing member 17, and the rear floor panel 27 of the rear frame 12. At this time, the ridge line 17f of the reinforcing member 17 connects the bent portion 29 at the boundary between the inclined portion 14 and the horizontal portion 15 of the rear frame 12 and the ridge line 16a at the rear portion of the rear cross member 16.

As is clear from FIGS. 1 and 4, a frame-shaped tailgate frame 30 opened and closed by a hatchback door is provided at the rear of the vehicle body, and the tailgate lower portion 31 having a closed cross section and extending in the vehicle width direction. The rear ends of the left and right extensions 13 project rearward from the rear ends. The rear floor panel 27 that connects the upper surfaces of the left and right rear frames 12 in the vehicle width direction includes an upward raised portion 27a that rises upward along the inclined portion 14 of the rear frame 12, and is a rear end of the upper raised portion 27a. Is connected to the rear end panel 32 that constitutes the front wall of the tailgate lower portion 31.

In this way, the subframe 18 that supports the high-voltage electrical components is surrounded by the left and right rear frames 12, the rear cross members 16 that connect the left and right rear frames 12, and the tailgate lower portion 31.

As is clear from FIGS. 3, 4 and 9, a flat plate-shaped end plate 33 is fixed to the rear end of the rear frame 12 with the rear end panel 32 interposed therebetween, and the extension 13 is connected to the rear surface of the end plate 33. Will be done. The U-shaped member 34, which is a shock absorbing member arranged between the left and right extensions 13, has a shock absorbing portion 34a extending in the vehicle width direction and a pair of left and right mounting portions extending forward from both ends of the shock absorbing portion 34a in the vehicle width direction. A U-shaped member 34 is attached to a pair of left and right brackets 33a protruding from the inside of the end plate 33 located behind the inner wall 25e of the inner member 25 in the vehicle width direction. Is fixed. The U-shaped member 34 and the left and right extensions 13 are made of a material having a lower strength than the rear frame 12, and their rear ends project rearward from the rear end of the tailgate lower portion 31.

As shown in FIGS. 2 and 8, a battery box 36 for driving an electric motor for traveling is mounted below the floor panel 35 connecting the inner members 23 of the left and right side sills 11. The battery box 36 includes a case 38 for accommodating a plurality of battery modules 37 inside, a cover 39 for closing the upper surface opening of the case 38, and a plurality of cases fixed to the upper surface of the bottom wall of the case 38 and extending in the vehicle width direction. A battery box cross member 40, a pair of left and right vertical frames 41 fixed to the outer surfaces of the left and right side walls of the case 38 and extending in the front-rear direction, and a plurality of mounting brackets 42 extending outward in the vehicle width direction from the vertical frame 33 are provided. , The mounting bracket 42 is mounted on the lower surface of the inner member 23 of the left and right side sills 11 with a plurality of bolts 43 penetrating from the bottom to the top.

Further, a plurality of floor cross members 44 extending in the vehicle width direction and connecting the inner members 23 of the left and right side sills 11 are provided on the upper surface of the floor panel 35 above the battery box 36, and on the lower surface of the floor panel 35. A pair of left and right floor frames 45 extending forward from the rear cross member 16 connecting the left and right rear frames 12 in the vehicle width direction are provided.

Therefore, in front of the connecting portion between the left and right rear frames 12 and the left and right side sills 11, the battery box cross member 40 and the floor cross member 44 are arranged between the left and right side sills 11 in the vehicle width direction, and behind the connecting portion. , The left and right rear frames 12 are connected by a rear cross member 16 extending in the vehicle width direction.

As shown in FIGS. 3 to 5, the front wheel house inner 46 and the rear wheel house inner 47, and the front wheel house inner 46 and the rear wheel house inner 47 are divided into two front and rear from the outer edge of the rear frame 12 in the vehicle width direction. The damper housing 48, which is sandwiched between the 47 and bulges inward in the vehicle width direction, stands up. The damper housing 48 includes a side wall portion 49 facing the inner surface of the suspension damper in the vehicle width direction (not shown), and a damper base 50 that constitutes the ceiling wall of the side wall portion 49 and supports the upper end of the suspension damper. The outer edge of the front wheel house inner 46, the damper housing 48, and the rear wheel house inner 47 in the vehicle width direction is connected to the inner edge of the wheel house outer 51 in the vehicle width direction. The space to be used is partitioned.

A part of the wheel house outer 51 extends upward to form the rear pillar outer 52, and the upper gusset 53 rising from the upper surface of the damper base 50 is connected to the rear pillar outer 52 to form the rear pillar 54 having a hollow closed cross section. NS. The outer sides of the wheel house outer 52 and the rear pillar 54 in the vehicle width direction are covered with the rear side panel 55. The bent portion 29 of the rear frame 12 and the inner end portion of the damper base 50 in the vehicle width direction are connected by a lower gusset 56 along the inner surface of the side wall portion 49 in the vehicle width direction.

In the rear wheel house configured in this way, the upper side of the side wall portion 19 of the damper housing 48 is inclined inward in the vehicle width direction in the front-rear direction (see line L1), and the upper side of the suspension damper axis is in the side view. It is inclined to the rear side (see line L2).

Next, the operation of the embodiment of the present invention having the above configuration will be described.

When the vehicle collides with the rear surface, the extensions 13 and the U-shaped member 34 protruding rearward from the rear ends of the left and right rear frames 12 are crushed, and then the tails located behind the rear ends of the left and right rear frames 12. Collision energy is absorbed by crushing the lower part 31 of the tailgate of the gate frame 30. At this time, the extension 13 and the U-shaped member 34, which have lower strength than the rear frame 12, are preferentially crushed while avoiding damage to the rear frame 12 to exert an energy absorbing effect. By arranging the U-shaped member 34 using the space sandwiched between the left and right extensions 13, the energy absorption effect can be enhanced while minimizing the length of the extension 13.

In particular, since the left and right mounting portions 34b of the U-shaped member 34 are connected to the rear of the inner wall 25e of the inner member 25 of the left and right rear frames 12 in the vehicle width direction, the collision of the rear surface collision input to the U-shaped member 34 The load can be efficiently transmitted from the mounting portion 34b to the upper and lower ridges of the inner wall 25e in the vehicle width direction of the inner member 25.

Further, the subframe 18 arranged between the left and right rear frames 12 is equipped with high-voltage electric parts such as an electric motor, and the subframe 18 connects the left and right rear frames 12 and the left and right rear frames 12. Since it is surrounded by the rear cross member 16 and the lower portion 31 of the tailgate, the high-voltage electrical components mounted on the subframe 18 can be protected from the impact of a rear collision. Moreover, since the left and right side frames 19 of the subframe 18 are arranged parallel to the inside of the left and right rear frames 12 in the vehicle width direction, the cross-sectional area of the side frame 19 of the subframe 18 is added to the cross-sectional area of the rear frame 12. As a result, the mounted object of the subframe 18 can be more reliably protected from the impact of the rear surface collision.

Further, since the rear frame 12 and the subframe 19 enhance each other's strength, the support rigidity of the extension 13 and the U-shaped member 34 with respect to the rear frame 12 is increased, and the extension 13 and the U-shaped member 34 are prevented from falling in the event of a rear collision. At the same time, crushing can be promoted and the amount of energy absorbed can be increased.

Further, in the rear frame 12, the inclined portion 14 on the front side is inclined with respect to the horizontal portion 15 on the rear side with the bent portion 29 in the center in the front-rear direction as a boundary, so that after the extension 13 and the U-shaped member 34 are completely crushed. The inclined portion 14 of the rear frame 12 bends inward in the vehicle width direction with the connecting portion with the side sill 11 as a fulcrum to absorb the collision energy. At this time, since the inner member 25 of the rear frame 12 has a U-shaped cross section that opens outward in the vehicle width direction, a large bending strength is exhibited and the amount of energy absorbed increases. Since the rear end of the side sill 11 and the front end of the rear frame 12 are connected by abutting the joining flanges 11b and 12b, the front portion of the rear frame 12 is extended forward and is overlapped and connected to the rear portion of the side sill 11. There is no need for it, and the weight can be reduced by suppressing the increase in weight.

Further, the inclined portion 14 of the rear frame 12 is connected to the rear cross member 16 connecting the left and right rear frames 12, the reinforcing member 17, and the rear floor panel 27 to form a triangular box structure portion 28 in a plan view. Therefore, the collision load of the rear surface collision can be distributed to the cross member 16 and the rear floor panel 27 via the box structure portion 28 having high strength. In particular, since the triangular horizontal wall 17a of the reinforcing member 17 constituting the box structure portion 28 is connected to the rear floor panel 27 in a wide area, the load is effectively distributed to the rear floor panel 27.

Moreover, since the ridge line 17f of the reinforcing member 17 connects the bent portion 29 at the boundary between the inclined portion 14 and the horizontal portion 15 of the rear frame 12 and the ridge line 16a at the rear portion of the rear cross member 16, the collision load of the rear surface collision is rear. The stress is transmitted to the rear cross member 16 via the highly rigid ridge lines 17f and 16a without concentrating the stress on the bent portion 29 of the frame 12.

Further, in the inclined portion 14 of the rear frame 12, since the joint flanges 25b and 26b at the lower edges of the inner member 25 and the outer member 26 extend downward, the inclined portion 14 faces downward when the collision load of the rear surface collision is input. The joint flanges 25b and 26b extending in the vertical direction effectively suppress the deformation in the vertical direction (see FIG. 7A). On the other hand, in the horizontal portion 15 of the rear frame 12, since the joint flanges 25c and 26c at the lower edges of the inner member 25 and the outer member 26 extend in the horizontal direction, when the collision load of the rear surface collision is input, the horizontal portion 15 The joint flanges 25c and 26c extending in the horizontal direction effectively suppress the deformation in the vehicle width direction (see FIG. 7B).

In the rear frame 12 of the present embodiment, since the opening of the inner member 25 that opens outward in the vehicle width direction is closed by the outer member 26 to form a closed cross section, the opening of the member that opens upward is made into another member. The cross-sectional area can be increased as compared with the conventional rear frame closed by. Hereinafter, the reason will be described with reference to FIG.

Considering the case where the dimension (horizontal width) of the rear frame in the vehicle width direction is limited, in the rear frame of the conventional example shown by the broken line in FIG. However, the width of the hollow portion is reduced and the cross-sectional area is reduced. On the other hand, in the inclined portion 14 of the rear frame 12 of the present embodiment shown by the solid line in FIG. 10A, the joint flanges 25a and 26a in which the inner member 25 and the outer member 26 project upward and the joint flange 25b protruding downward , 26b is provided, so that the width of the hollow portion of the rear frame 12 can be secured to the full limit width, and the cross-sectional area is increased by the amount indicated by the diagonal line as compared with the conventional example.

The horizontal portion 15 of the rear frame 12 of the present embodiment shown by the solid line in FIG. 10B includes joint flanges 25c and 26c in which the inner member 25 and the outer member 26 project in the horizontal direction as in the comparative example. Therefore, the cross-sectional area is reduced, but since it is not necessary to provide a joint flange at the inner end of the inner member 25 in the vehicle width direction, the width of the hollow portion of the rear frame 12 can be secured by that amount, which is indicated by the diagonal line. However, the cross-sectional area is increased as compared with the conventional example.

Further, since the beads 25d and 26d extending from the bent portion 29 toward the inclined portion 14 side and the horizontal portion 15 side are formed in the vertical intermediate portion of the inner member 25 and the outer member 26 of the rear frame 12, the weight is increased. The strength of the rear frame 12 can be increased while minimizing the problem.

Further, in a state where the first widening portion 11a at the rear portion of the side sill 11 and the second widening portion 12a at the front portion of the inclined portion 14 of the rear frame 12 are connected by the joining flanges 11b and 12b, the vehicle width direction of the first widening portion 11a Since the inner wall and the inner wall in the vehicle width direction of the inclined portion 14 are linearly continuous in a plan view (see the chain line L in FIG. 3), the side sill 11 and the rear frame 12 are connected by lightweight joining flanges 11b and 12b, and the rear surface is connected. The collision load of the collision can be efficiently transmitted from the rear frame 12 to the side sill 11 and dispersed.

In particular, since the rear frame 12 is made of a hot stamping material having high moldability and the side sill is made of a high-tensile material having high ductility, the rear frame 12 having a complicated shape can be easily molded with a hot stamping material having high moldability. In addition to this, the side sill 11 on which stress is concentrated at the time of a rear surface collision can be made of a highly ductile high-tensile material to effectively absorb the collision energy.

Then, the rear end of the rear frame 12 and the rear end of the upper raised portion 27a of the rear floor panel 27 are connected to the rear end panel 32 forming the front surface of the tailgate lower portion 31, so that the upper raised portion 27a of the rear floor panel 27 is connected. It is possible to secure a space below for mounting large parts such as an electric motor for driving the rear wheels.

Further, since the rear frame 12 is connected to the damper housing 48 at the bent portion 29 at the boundary between the horizontal portion 15 on the rear side and the inclined portion 14 on the front side, the load input from the damper is applied from the damper housing 48 to the bent portion of the rear frame 12. It can be transmitted to and supported by 29. At this time, since the damper housing 48 is connected to the rear pillar 54 via the upper gusset 53, the load input from the damper can be transmitted from the damper housing 48 to the rear pillar 54 via the upper gusset 53 to support the rear pillar 54 more reliably. ..

Further, in front of the connection portion between the left and right rear frames 12 and the left and right side sills 11, a plurality of battery box cross members 40 of the battery box 36 mounted below the floor panel 35 and a plurality of battery box cross members 40 provided on the upper surface of the floor panel 35. The floor cross member 44 is arranged between the left and right side sills 11 in the vehicle width direction, and behind the connection portion, the left and right rear frames 12 are provided on the lower surface of the rear floor panel 27 by a rear cross member 16 extending in the vehicle width direction. Since they are connected, the collision load of the rear collision can be supported by the rear cross member 16, the floor cross member 44, and the battery box cross member 40, and the battery module 37 housed in the battery box 36 can be protected.

Although the embodiments of the present invention have been described above, the present invention can make various design changes without departing from the gist thereof.

For example, although the electric vehicle is illustrated in the embodiment, the present invention can be applied to a vehicle other than the electric vehicle.

11 ... Side sill 11a ... 1st widening part 11b ... Joint flange 12 ... Rear frame 12a ... 2nd widening part 12b ... Joint flange 14 ... Inclined part 15 ... Horizontal part 16 ... Rear cross member (cross connecting between left and right rear frames) Members) 16a ... Ridge line 17 ... Reinforcing member 17f ... Ridge line 25 ... Inner member 25b ... Joint flange 25c ... Joint flange 26 ... Outer member 26d ... Bead 27 ... Rear floor panel 28 ... Box structure part 29 ... Bending part 35 ... Floor panel 36 ... Battery box 40 ... Battery box cross member (battery box cross member) 44 ... Floor cross member (floor panel cross member) 48 ... Damper housing 50 ... Damper base 53 ... Upper gusset 54 ... Rear pillar 56 ... Lower gusset

Claims (10)

A pair of left and right rear frames (12) extending rearward from the rear ends of the pair of left and right side sills (11) and a cross member (16) extending in the vehicle width direction and connecting between the left and right rear frames (12) are provided. The body structure of an automobile
The rear frame (12) connects an inner member (25) having a substantially U-shaped cross section that opens outward in the vehicle width direction and an outer member (26) that closes the opening of the inner member (25). The rear frame (12) and the cross member (16) are connected by a reinforcing member (17) having an L-shaped cross section to form a triangular box structure portion (28) in a plan view. The body structure of an automobile, which is characterized by the fact that it has been done. The rear frame (12) is composed of an inclined portion (14) that inclines inward in the vehicle width direction toward the rear and a horizontal portion (15) that extends substantially horizontally from the rear end of the inclined portion (14) toward the rear. The lower edge of the inner member (25) of the rear frame (12) is a joint flange (25b) extending downward at the inclined portion (14), and the lower edge of the outer member (26) of the rear frame (12). A joint flange (25c) extending outward in the vehicle width direction at the horizontal portion (15) is connected to the lower edge of the outer member (26) of the rear frame (12). Item 1. The vehicle body structure of the automobile according to Item 1. The rear frame (12) is provided with a bent portion (29) at the boundary between the inclined portion (14) on the front side and the horizontal portion (15) on the rear side, and the outer member (26) of the rear frame (12) is bent. The vehicle body structure according to claim 1, further comprising a bead (26d) extending in the front-rear direction along a middle portion in the vertical direction centered on the portion (29). The rear portion of the side sill (11) is provided with a first widening portion (11a) that widens inward in the vehicle width direction, and the front portion of the inclined portion (14) of the rear frame (12) widens outward in the vehicle width direction. Joint flanges (11b, 12b) provided with a second widening portion (12a) and projecting in a direction orthogonal to the front-rear direction between the rear end of the first widening portion (11a) and the front end of the second widening portion (12a). The first aspect of claim 1, wherein the inner wall in the vehicle width direction of the first widening portion (11a) and the inner wall in the vehicle width direction of the inclined portion (14) are connected in a straight line in a plan view. Car body structure. The vehicle body structure according to claim 11, wherein the rear frame (12) is made of a hot stamping material, and the side sill (11) is made of a high-tensile material. The rear frame (12) is provided with a bent portion (29) at the boundary between the inclined portion (14) on the front side and the horizontal portion (15) on the rear side, and the bent portion (29) is a damper housing (48) and an upper gusset. The vehicle body structure according to claim 1, wherein the rear pillar (54) is connected to the rear pillar (54) via the (53). The ridge line (17f) of the reinforcing member (17) is formed between the bent portion (29) at the boundary between the inclined portion (14) and the horizontal portion (15) of the rear frame (12) and the rear portion of the cross member (16). The vehicle body structure according to claim 1, wherein the vehicle body structure is connected to a ridge line (16a). The rear frame (12) is provided with a bent portion (29) at the boundary between the inclined portion (14) on the front side and the horizontal portion (15) on the rear side, and the bent portion (29) is connected to the damper housing (48). The vehicle body structure according to claim 1, wherein the vehicle body structure is characterized by this. The upper part of the damper housing (48) is inclined inward in the vehicle width direction, the axis of the damper housed in the damper housing (48) is inclined rearward, and the damper base (50) of the damper housing (48) is inclined. ) Is connected to the rear pillar (54) via the upper gusset (53) and is connected to the bent portion (29) of the rear frame (12) via the lower gusset (56). 8. The vehicle body structure of the automobile according to 8. In front of the connection portion between the left and right rear frames (12) and the left and right side sills (11), a cross member (40) of a battery box (36) mounted below the floor panel (35) and the floor panel. The cross member (44) of (35) is arranged between the left and right side sills (11) in the vehicle width direction, and behind the connection portion, the space between the left and right rear frames (12) is on the rear floor panel (27). The vehicle body structure according to claim 1, wherein the cross member (16) is connected to the cross member (16).

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