Rear body structure

Abstract

The present invention provides a vehicle body rear structure capable of supporting loads input from a side collision using a first floor cross member, for example, without reinforcing a rear side frame with a reinforcing member. The vehicle body rear structure comprises: a first floor cross member disposed in front of the vehicle relative to a battery and connected to a rear side frame extending in the vehicle front-rear direction on the vehicle widthwise outboard side; and a second floor cross member disposed behind the vehicle relative to the battery. The first floor cross member includes a widened portion at an end portion, the widened portion being widened in the vehicle front-rear direction to a position overlapping the battery, and the boundary between the widened portion and the rear side frame being disposed in a position overlapping the battery in a side view.

Description

Technical Field

[0001] The invention relates to a vehicle body rear structure.

[0002] This application claims priority based on Japanese Patent Application No. 2021-155759 filed in Japan on September 24, 2021, the contents of which are incorporated herein by reference. Background Art

[0003] For example, a known vehicle rear structure includes an electric storage device disposed below a rear seat and surrounded by a vehicle body frame arranged in a lattice pattern to protect the device. The vehicle body frame forms a lattice pattern with left and right rear side frames disposed on the left and right sides of the electric storage device in the vehicle width direction, a first floor cross member disposed in front of the electric storage device, and a second floor cross member disposed in the rear of the device.

[0004] The first and second floor cross members extend in the vehicle width direction and are mounted on the left and right rear side frames, respectively. Thus, the first and second floor cross members can absorb loads inputted, for example, by a side collision (see, for example, Japanese Patent No. 6631472). Summary of the Invention

[0005] In the rear vehicle body structure disclosed in Japanese Patent No. 6631472, a first floor cross member is provided in front of the vehicle, in front of the power storage device, and a second floor cross member is provided at a distance from the first floor cross member and at the rear of the vehicle. Therefore, a side collision could potentially cause a load to be applied to the rear frame between the first and second floor cross members in the vehicle's longitudinal direction. In this case, the rear frame could deform inward in the vehicle width direction (i.e., toward the power storage device), making it difficult to protect the power storage device from the applied load.

[0006] As a countermeasure, one possible solution is to reinforce the rear side frame with a reinforcing member to protect the power storage device from the input load. However, reinforcing the rear side frame with a reinforcing member increases the number of components and their size, which in turn increases the weight of the vehicle body, making it undesirable from the perspective of reducing vehicle weight.

[0007] An object of the present invention is to provide a vehicle body rear structure capable of receiving a load inputted due to a side collision by a first floor cross member without reinforcing a rear side frame with a reinforcing member, for example.

[0008] In order to achieve the above-mentioned object, the vehicle body rear structure according to the solution of the present invention adopts the following structure.

[0009] (1) The present invention is directed to a vehicle body rear structure (e.g., vehicle body rear structure 10 of an embodiment), comprising: a first floor cross member (e.g., first floor cross member 14 of an embodiment), which is arranged in front of the vehicle relative to a battery (e.g., battery 121 or battery module 121 of an embodiment) and is connected to a rear side frame (e.g., rear side frame 13 of an embodiment) extending in the vehicle front-rear direction on the outside in the vehicle width direction; and a second floor cross member (e.g., second floor cross member 15 of an embodiment), which is arranged in the vehicle rear relative to the battery, wherein the first floor cross member includes a widened portion (e.g., widened portion 14B of an embodiment) at an end portion, the width of the widened portion in the vehicle front-rear direction being widened to a position overlapping with the battery, and a boundary portion between the widened portion and the rear side frame (e.g., boundary portion 88 of an embodiment) is arranged in a position overlapping with the battery when viewed from the side.

[0010] According to the above-mentioned solution (1), the interface between the widened portion of the first floor cross member and the rear side frame is positioned so as to overlap the battery when viewed from the side. Therefore, the interface can bear a load (hereinafter sometimes referred to as a side collision load) input from the outside of the battery in the vehicle width direction, for example, in a side collision. As a result, the side collision load can be efficiently transferred from the interface to the center of the first floor cross member in the vehicle width direction, allowing the first floor cross member to absorb the side collision load.

[0011] Therefore, the deformation of the vehicle body side portion (eg, the widened portion, the rear side frame, etc.) located outside the battery in the vehicle width direction can be suppressed, thereby suppressing damage (deformation) of the battery and protecting the battery.

[0012] By arranging the boundary between the widened portion and the rear side frame at a position overlapping the battery, the first floor cross member can absorb the side collision load without reinforcing the rear side frame with a reinforcing member, thereby reducing the weight of the vehicle body.

[0013] Here, it is contemplated that, in the event of an excessive side impact load, such as from a side collision, the widened portion (i.e., the first floor cross member) may bend toward the rear side frame. Meanwhile, the widened portion contacts the rear side frame by forming an interface therewith. Therefore, in the event of an excessive side impact load, such as from a side collision, the widened portion can be supported by the rear side frame, thereby preventing the widened portion from bending (or collapsing).

[0014] This prevents the widened portion from bending toward the rear frame (i.e., the battery) due to excessive side impact loads, allowing the rear side frame to transfer the excessive side impact loads toward the center of the first floor cross member. Furthermore, by preventing the widened portion from collapsing, it can be deformed appropriately to absorb the impact energy caused by excessive side impact loads. Consequently, even in the face of excessive side impact loads, damage (deformation) to the battery can be prevented, protecting the battery.

[0015] (2) In the above aspect (1), the widened portion may have an inclined surface (for example, the inclined wall 52 of the embodiment) on a front surface located on the vehicle front side, the inclined surface being inclined upward toward the vehicle rear.

[0016] According to the above-mentioned solution (2), an inclined surface is formed on the front surface of the widened portion. Therefore, for example, a ridgeline can be formed at the intersection of the inclined surface and another surface on the front surface of the widened portion. This ridgeline is formed in a V-shape and extends generally in the vehicle width direction. This increases the ridgeline of the first floor cross member. Consequently, a side impact load input to the end portion of the first floor cross member (i.e., the widened portion) can be efficiently transferred to the center of the first floor cross member.

[0017] Furthermore, the side collision load can also be transmitted to the front floor panel provided in front of the vehicle at the first floor cross member.

[0018] For example, the end (widened portion) of the first floor cross member is located at the rear lower portion of the opening for the rear door. Therefore, by forming an inclined surface on the front surface of the widened portion, a larger footwell can be secured on the outer side of the vehicle width direction within the vehicle cabin. This makes it easier for passengers to enter and exit the vehicle.

[0019] (3) In the above-mentioned scheme (2), it is also possible that the first floor crossbeam has a ridge line (for example, the first ridge line 92 of the embodiment) formed by the intersection of the front surface and the top formed from the front surface toward the rear of the vehicle (for example, the top 61 of the upper side member of the embodiment), and the ridge line has: a first outer ridge line (for example, the first outer ridge line 95 of the embodiment), which is formed by the intersection of the inclined surface and the top; and a first central side ridge line (for example, the first central side ridge line 96 of the embodiment), which is formed by the intersection of the portion of the inclined surface in the front surface in the vehicle width direction (for example, the central side front wall 54 of the embodiment) and the top, wherein the first outer ridge line is offset toward the rear of the vehicle relative to the first central side ridge line.

[0020] According to the above-mentioned solution (3), the first outer ridgeline on the inclined surface side (widened portion side) of the ridgelines of the first floor cross member is offset toward the rear of the vehicle relative to the first center ridgeline on the center side in the vehicle width direction. Therefore, the first outer ridgeline can be brought closer to the battery side in the vehicle front-rear direction. As a result, a side impact load, such as that input from the vehicle width direction outside of the battery due to a side collision, can be received by the first outer ridgeline and efficiently transferred to the first center ridgeline. In other words, the side impact load can be efficiently transferred to the first floor cross member.

[0021] (4) In the above-mentioned scheme (3), the first outer ridgeline may be offset toward the rear of the vehicle relative to the first central side ridgeline starting from the outer end of the battery on the outside in the vehicle width direction of the battery (for example, the outer end 121a of the battery in the embodiment), and the first floor crossbeam may have another ridgeline (for example, the second ridgeline 93 of the embodiment), which is formed by the intersection of the inclined surface in the front surface and another surface below the inclined surface (for example, the outer front wall 53 of the embodiment), and is located below the first outer ridgeline.

[0022] According to the above-mentioned embodiment (4), another ridgeline is formed below the first outer ridgeline among the ridgelines. Therefore, the first outer ridgeline and the other ridgeline can bear the side impact load, for example, input from the vehicle width direction outer side of the battery due to a side collision. This allows the side impact load to be more efficiently transmitted to the first floor cross member.

[0023] (5) In the above-mentioned scheme (3), the vehicle front-rear width (for example, the vehicle front-rear width W1 of the embodiment) of the portion of the widening portion that overlaps with the rear side frame in the vehicle width direction (for example, the maximum widening portion 14C of the embodiment) may be set to the maximum.

[0024] According to the above-mentioned solution (5), the vehicle longitudinal width is set to the maximum at the portion of the widened portion that overlaps with the rear side frame. Therefore, for example, the widened portion can be brought into contact with or close to the rear side frame in the vehicle longitudinal direction. As a result, the rear side frame can suppress bending (collapse) of the widened portion toward the rear side frame caused by a side collision load. Consequently, the side collision load can be efficiently transmitted to the first floor cross member, allowing the first floor cross member to absorb the side collision load.

[0025] Furthermore, even in the event of an excessive side impact load, such as from a side collision, the rear side frame can suppress the collapse of the widened portion toward the rear side frame caused by the side impact load. Consequently, the excessive side impact load can be efficiently transmitted to the first floor cross member. Furthermore, by suppressing the collapse of the widened portion, the excessive side impact load can be absorbed by appropriately deforming the widened portion (particularly the portion that maximizes the vehicle's longitudinal width) to absorb the impact energy caused by the excessive side impact load.

[0026] (6) In the above-mentioned scheme (2), the rear vehicle body structure may also include a storage portion for configuring the battery (for example, the battery storage portion 16 of the embodiment) surrounded by the first floor cross member, the second floor cross member and the rear side frame, and the storage portion includes a side wall (for example, the storage side wall 119 of the embodiment) connected to the widened portion from the end of the second floor cross member (for example, the left outer end 114a of the storage rear end portion of the embodiment).

[0027] According to the above-mentioned embodiment (6), a housing portion is provided that is surrounded by the first floor cross member, the second floor cross member, and the rear side frame. A battery is disposed in the housing portion, and the side wall of the housing portion is connected to the widened portion from the end of the second floor cross member. Therefore, for example, a side collision load input to the widened portion can be transferred to the first floor cross member and then to the second floor cross member via the side wall of the housing portion.

[0028] In other words, the side collision load can be efficiently transmitted to the first and second floor cross members. As a result, the first and second floor cross members can support the side collision load. This reduces deformation of the vehicle body side portions (e.g., the widened portion, rear side frames, etc.) located outboard of the battery in the vehicle width direction, thereby preventing damage (deformation) to the battery and protecting it.

[0029] (7) In the above-mentioned aspect (1), the first floor cross member may be formed so that its height (for example, height H in the embodiment) increases toward the upper side of the vehicle as it goes outward in the vehicle width direction, and the widened portion may be set to be the highest.

[0030] According to the above-mentioned solution (7), the widened portion of the first floor cross member is set to be the highest. This ensures a large cross-sectional area for the widened portion, thereby improving strength and rigidity. Consequently, the widened portion can be appropriately deformed by a side collision load to absorb the impact energy caused by the side collision load. This prevents damage (deformation) to the battery caused by the side collision load, thereby protecting the battery.

[0031] Furthermore, the first floor cross member is formed so that its height increases toward the top of the vehicle as it moves outward in the vehicle width direction. Therefore, the height of the center portion of the first floor cross member, located on the inner side of the widened portion in the vehicle width direction, can be kept lower than that of the widened portion. This ensures space for the battery wiring to pass through the center portion of the first floor cross member.

[0032] (8) In the above-mentioned scheme (5), the rear structure of the vehicle body may also include a metal battery cover (for example, the battery cover 18 of the embodiment) connected to the first floor cross member and the second floor cross member and covering the upper part of the battery, and the battery cover has a vehicle width outer side connection portion (for example, the left and right vehicle width outer side connection portions 134 of the embodiment) at the outer side end of the cover in the vehicle width direction, which is connected across the inclined surface in the vehicle front-rear direction, and the vehicle width outer side connection portion has: a rear side fixing portion (for example, the rear side fixing portion 137 of the embodiment), which is connected to the rear side frame; and a front side fixing portion (for example, the front side fixing portion 136 of the embodiment), which is connected to the lower part of the inclined surface at the front surface of the first floor cross member located on the front side of the vehicle.

[0033] According to the above-mentioned solution (8), the metal battery cover covering the upper portion of the battery is connected to the first floor cross member and the second floor cross member. Furthermore, the vehicle width outer side connection portion of the battery cover is connected across the inclined surface. By making the battery cover from metal, the strength and rigidity of the battery cover can be improved. Therefore, the inclined surface of the widened portion can be reinforced by the high-strength and high-rigidity vehicle width outer side connection portion, thereby improving the strength and rigidity of the inclined surface (i.e., the first floor cross member).

[0034] This allows the side collision load to be transferred to the metal battery cover via the widened portion and the vehicle widthwise outer connecting portion, allowing the battery cover to support the side collision load. This suppresses deformation of the first floor cross member caused by the side collision load, thereby preventing damage (deformation) to the battery and protecting it.

[0035] Furthermore, the rear fixing portion of the battery cover's vehicle-width-outboard connection is connected to the rear side frame. The rear side frame is connected to the second floor cross member. Therefore, the first floor cross member, rear side frame, and second floor cross member can be connected via the battery cover. This allows the side collision load to be transferred to the components surrounding the battery, which are comprised of the first floor cross member, rear side frame, second floor cross member, and battery cover. This improves the strength and rigidity of the components surrounding the battery against the side collision load, preventing damage (deformation) to the battery and protecting it.

[0036] (9) In the above-mentioned scheme (8), the first floor cross beam may also include: a first floor cross beam upper side member (for example, the first upper beam 36 of the embodiment), which is formed by the front surface and the top; and a first floor cross beam lower side member (for example, the first lower beam 37 of the embodiment), which is connected to the first floor cross beam upper side member, wherein the rear side frame includes a rear side frame upper side member (for example, the rear side frame upper side member 28 of the embodiment) that closes the upper opening, and the rear side fixing portion is connected to a position where the rear side frame upper side member, the first floor cross beam upper side member and the first floor cross beam lower side member overlap in the upper and lower directions.

[0037] According to the solution (9) above, the rear fixing portion of the battery cover is connected to a position where it overlaps with the rear frame upper member, the first floor cross member upper member, and the first floor cross member lower member. Therefore, the four components, namely, the rear fixing portion, the rear frame upper member, the first floor cross member upper member, and the first floor cross member lower member, can be overlapped and connected. This improves the strength and rigidity of the connection portion where the four components overlap and connect, and improves the efficiency of transmitting the side collision load.

[0038] As a result, the side collision load can be efficiently transmitted to the four components: the rear fixing portion (i.e., the battery cover), the rear frame upper member, the first floor cross member upper member, and the first floor cross member lower member. This prevents damage (deformation) to the battery and protects it.

[0039] Furthermore, by overlapping and connecting the four components—the rear fixing portion, the rear frame upper member, the first floor cross member upper member, and the first floor cross member lower member—the strength and rigidity of the connection between the four components can be improved. Consequently, the connection between the four components can support loads such as those from the rear seats positioned above the battery cover, improving the riding comfort of seated occupants.

[0040] (10) In the above-mentioned scheme (9), the first floor cross beam upper side member may also include: an upper side member body (for example, the upper side member body 41 of the embodiment), which forms the main part of the first floor cross beam upper side member; and a reinforcement member (for example, the reinforcement member 42 of the embodiment), which is connected to the end portion on the outside in the vehicle width direction of the upper side member body and forms the upper surface of the end portion of the first floor cross beam upper side member, wherein the rigidity of the reinforcement member is set higher than the rigidity of the upper side member body, and the inner end portion of the reinforcement member on the inside in the vehicle width direction (for example, the inner end portion 42b of the embodiment) extends from the cross beam end portion on the outside in the vehicle width direction of the first floor cross beam to a position closer to the inside in the vehicle width direction than the widening portion.

[0041] According to the above-mentioned solution (10), the upper surface of the end portion of the upper side member of the first floor cross member is formed by a reinforcement member that is a separate body from the main body of the upper side member. Moreover, the strength and rigidity of the reinforcement member are set higher than those of the main body of the upper side member. In addition, the inner end portion of the reinforcement member is extended to a position that is closer to the inside in the vehicle width direction than the widening portion. Therefore, the strength and rigidity of the upper surface of the end portion of the upper side member of the first floor cross member can be set higher by the reinforcement member. The upper surface of the end portion of the upper side member of the first floor cross member is included in the widening portion. As a result, the strength and rigidity of the widening portion can be set higher.

[0042] Furthermore, the upper surface of the end portion of the first floor cross member upper member overlaps and connects with the battery cover's rear fixing portion, the rear frame upper member, and the first floor cross member lower member, forming a connection portion with these three members. This further enhances the strength and rigidity of the connection portion formed by these four members, and improves the rigidity of the connection between the rear frame and the battery cover.

[0043] Therefore, by setting the strength and rigidity of the widened portion high and increasing the connection rigidity between the rear side frame and the battery cover, it is possible to improve the protection performance of the battery against, for example, a side collision load.

[0044] Furthermore, the upper surface of the end portion of the first floor cross member upper side member is formed from a reinforcement member that is separate from the upper side member main body. Therefore, for example, by selecting a different reinforcement member corresponding to a different model, the upper side member main body can be shared across different models. Thus, by selecting reinforcement members corresponding to different models, the upper side member main body, which constitutes the main portion of the first floor cross member, and the first floor cross member lower side member can be shared across different models.

[0045] According to the aspect of the present invention, for example, the load inputted due to a side collision can be received by the first floor cross member without reinforcing the rear side frame with a reinforcing member. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is an exploded perspective view showing a battery cover disassembled from the vehicle body rear structure according to the embodiment of the present invention.

[0047] Figure 2 It is a plan view of the vehicle body rear structure in the embodiment of the present invention.

[0048] Figure 3 This is a rear view of the vehicle body rear structure according to the embodiment of the present invention as viewed from the lower side behind the vehicle.

[0049] Figure 4 It is along Figure 2 Cross-sectional view taken along line IV-IV.

[0050] Figure 5 It is along Figure 2 Cross-sectional view taken along the V-V line.

[0051] Figure 6 It is along Figure 2 Cross-sectional view taken along line VI-VI.

[0052] Figure 7 It is along Figure 2 Cross-sectional view taken along line VII-VII.

[0053] Figure 8 It will Figure 2 An enlarged top view of part VIII.

[0054] Figure 9 This is an exploded perspective view of the first floor cross member and the battery housing portion of the vehicle body rear structure in the embodiment of the present invention.

[0055] Figure 10 It will Figure 1 An enlarged top view of the X portion.

[0056] Figure 11 It is from Figure 6 A top view of the rear vehicle structure with the battery pack and rear side frame exploded.

[0057] Figure 12 This is a perspective view of a battery cover connected to a first floor cross member and a second floor cross member of the vehicle body rear structure in the embodiment of the present invention.

[0058] Figure 13 It is along Figure 12 Cross-sectional view taken along line XIII-XIII. DETAILED DESCRIPTION

[0059] The following describes a rear vehicle body structure according to an embodiment of the present invention based on the accompanying drawings. It should be noted that in the accompanying drawings, arrow FR indicates the front of the vehicle, arrow UP indicates the top of the vehicle, and arrow LH indicates the left side of the vehicle. In the embodiments, as an example, the rear vehicle body structure is applied to an electric vehicle such as a hybrid vehicle equipped with an electric motor for propulsion. However, the rear vehicle body structure is not limited to this embodiment and can also be applied to various other vehicles.

[0060] It should be noted that the vehicle body rear structure is a substantially bilaterally symmetrical structure, and the same reference numerals are given to the left and right components, and detailed description of the right components will be omitted.

[0061] Rear body structure

[0062] like Figures 1 to 3As shown, the vehicle body rear structure 10 includes, for example: left and right rocker rails 12; left and right rear side frames 13 arranged on the inner side of the rocker rails 12 in the vehicle width direction; a first floor cross member (front cross member) 14 arranged on the vehicle front side of the rear side frames 13; a second floor cross member (rear cross member) 15 arranged at a position farther rearward of the vehicle than the first floor cross member 14; and a battery housing portion (housing portion) 16, a power storage device 17, and a battery cover 18 arranged between the first floor cross member 14 and the second floor cross member 15 and on the inner side of the rear side frames 13 in the vehicle width direction.

[0063] Hereinafter, the left rocker 12 may be simply referred to as “rocker 12 ”, and the left rear side frame 13 may be simply referred to as “rear side frame 13 ”.

[0064] <Lower side sill>

[0065] like Figure 1 、 Figure 3 、 Figure 4 As shown, the rocker 12 extends in the vehicle longitudinal direction, for example, outboard of the front floor panel 22 in the vehicle width direction. The rocker 12 is formed into a rectangular closed cross section by, for example, an inner rocker 24 and an outer rocker 25, and is a high strength and rigidity member constituting the vehicle body frame.

[0066] A front floor panel 22 is provided between the left and right rocker members 12. The rear end of the front floor panel 22 is connected to a first floor cross member 14, described later, and the front floor panel 22 is located on the vehicle front side relative to the first floor cross member 14. The front floor panel 22 forms the floor surface of the vehicle interior.

[0067] A rear side frame 13 is connected to a rear end portion 12 a of the rocker 12 .

[0068] <Rear side frame>

[0069] The front end portion 13a of the rear side frame 13 is connected to the rear end portion 12a of the rocker 12 from the inside in the vehicle width direction. Hereinafter, the front end portion 13a of the rear side frame 13 may also be referred to as the "frame front end portion 13a". The rear side frame 13 is arranged on the outside in the vehicle width direction relative to the battery accommodating portion 16 and the second floor cross member 15, and extends from the rear end portion 12a of the rocker 12 toward the rear of the vehicle. The rear side frame 13 includes a rear side frame lower part 27 and a rear side frame upper part 28 arranged on the upper part of the rear side frame lower part 27. The rear side frame lower part 27 has a lower side part frame front end portion 27a and a lower side part frame main body portion (not shown).

[0070] The front end portion 27a of the lower side member frame is connected to the rear end portion 12a of the rocker 12 from the inside in the vehicle width direction. The front end portion 27a of the lower side member frame is positioned further inward in the vehicle width direction than the rear end portion 12a of the rocker 12. The lower side member inner wall 31 and the lower side member bottom portion 32 are formed to have an L-shaped cross-section. The upper flange 31a of the lower side member inner wall 31 is connected from below to the left storage end portion 115 (described later) of the battery storage portion 16 and the rear floor panel 35.

[0071] The rear floor panel 35 is provided between the left rear side frame 13 and the right rear side frame 13. The rear floor panel 35 is connected to the second floor cross member 15 described later and is provided on the vehicle rear side relative to the second floor cross member 15. The rear floor panel 35 forms the floor surface of the luggage compartment, for example.

[0072] The outer flange 32a of the lower side member bottom 32 is connected from below to the bottom of the inner rocker 24. Therefore, the lower side member frame front end 27a (i.e., the lower side member inner wall 31 and the lower side member bottom 32) together with the inner side wall 24a of the inner rocker 24 form a U-shaped cross-section with an open top. Furthermore, the lower side member frame front end 27a is reinforced by a lower side member reinforcement 33.

[0073] Furthermore, the lower side member frame main body portion (not shown) is formed in a U-shaped cross section with an open top.

[0074] Specifically, the rear frame lower panel 27 formed by the lower panel front end portion 27a and the lower panel body has a U-shaped cross section with an open top.

[0075] Specifically, the inner flange 28b (also refer to Figure 8 ) is connected from above to the left storage end portion 115 (described later) of the battery storage portion 16 and the rear floor panel 35. In addition, the outer flange 28c of the upper side member frame front end portion 28a of the rear side frame upper side member 28 (also refer to Figure 8 ) is connected from above to the top of the inner rocker 24. As a result, the upper opening of the U-shaped cross section formed by the lower side member frame front end portion 27a and the inner side wall 24a of the inner rocker 24 is closed by the upper side member frame front end portion 28a.

[0076] Thus, a closed cross section with a rectangular cross section is formed by the lower side member frame front end portion 27a, the inner side wall 24a of the inner rocker 24, and the upper side member frame front end portion 28a. The lower side member frame front end portion 27a and the upper side member frame front end portion 28a form the frame front end portion 13a of the rear side frame 13. That is, the frame front end portion 13a of the rear side frame 13 and the inner side wall 24a of the inner rocker 24 form a closed cross section with a rectangular cross section. The upper side member frame front end portion 28a is connected to the first floor cross member 14 from above (refer to Figure 7 ).

[0077] Furthermore, the rear side frame upper part 28 includes an upper part frame main body portion (not shown) extending from the rear end portion of the upper part frame front end portion 28a toward the rear of the vehicle. This upper part frame main body portion closes the upper opening of the lower part frame main body portion (not shown). Thus, a closed cross-section with a rectangular cross-section is formed by the lower part frame main body portion and the upper part frame main body portion. The lower part frame main body portion and the upper part frame main body portion form the frame main body portion of the rear side frame 13. In other words, the frame main body portion of the rear side frame 13 is formed into a closed cross-section with a rectangular cross-section.

[0078] The closed cross section formed by the frame main body (not shown) communicates with the closed cross section formed by the lower side member frame front end portion 27a and the inner side wall 24a of the inner rocker 24. Specifically, the rear side frame 13 is formed into a rectangular closed cross section extending in the vehicle front-rear direction and is a member having high strength and rigidity that constitutes the vehicle body framework.

[0079] <First floor beam>

[0080] like Figure 3 、 Figure 5 As shown, a first floor cross member 14 is connected (linked) to the frame front end portion 13a of the left rear side frame 13 and the frame front end portion 13a of the right rear side frame 13. The first floor cross member 14 extends in the vehicle width direction and is connected in a state of abutting against the rear end portion 12a of the left rocker 12 and the rear end portion 12a of the right rocker 12, thereby being mounted on the rear end portion 12a of the left rocker 12 and the rear end portion 12a of the right rocker 12. In addition, the first floor cross member 14 is relatively close to the battery storage portion 16 and the power storage device 17 (see FIG. 1 ). Figure 2 ) is configured in front of the vehicle.

[0081] like Figure 3 、 Figure 6 、 Figure 7 As shown, the first floor cross member 14 includes a first upper member (first floor cross member upper member) 36 and a first lower member (first floor cross member lower member) 37 disposed below the first upper member 36. The first upper member 36 forms the upper portion of the first floor cross member 14. The first lower member 37 is connected to the first upper member 36 to form the lower portion of the first floor cross member 14.

[0082] <First upper beam>

[0083] The first upper member 36 includes an upper side member main body 41 and a reinforcement member 42 provided on the vehicle width direction outer side of the upper side member main body 41 (see also Figure 9The upper member body 41 forms the main portion of the first upper member 36. The upper member body 41 includes a first upper member body portion 44 and a second upper member body portion 45 disposed behind the first upper member body portion 44. The first upper member body portion 44 includes an upper member front wall (front surface) 47, a first upper member flange 48 disposed at the lower portion of the upper member front wall 47, and a first top flange 49 disposed at the upper portion of the upper member front wall 47.

[0084] The upper side member front wall 47 stands upward relative to the front floor panel 22. In addition, the upper side member front wall 47 extends in the vehicle width direction and is mounted on the rear end portion 12a of the left and right rocker 12 (see Figure 2 ).

[0085] The first upper flange 48 is formed from the lower side of the upper front wall 47 toward the vehicle front and is connected from below to the front floor 22. The first top flange 49 is formed from the upper side of the upper front wall 47 toward the vehicle rear.

[0086] That is, the first upper panel body portion 44 is formed into a crank-shaped cross-section by the upper panel front wall 47 , the first upper panel flange 48 , and the first top flange 49 .

[0087] like Figure 7 、 Figure 8 As shown, the upper side member front wall 47 has upper side member front wall outer end portions 51 at the left and right outer ends in the vehicle width direction. The upper side member front wall outer end portions 51 have an inclined wall (inclined surface) 52 and a portion 53 below the inclined wall 52 (the other surface below the inclined surface). Hereinafter, the portion 53 below the inclined wall 52 of the upper side member front wall 47 may also be referred to as the "outer side front wall 53." The inclined wall 52 slopes upward from the upper edge of the outer side front wall 53 toward the rear of the vehicle.

[0088] like Figure 6 、 Figure 8 As shown, a second upper side member main body 45 is provided at the vehicle rear of the first upper side member main body 44 along the first upper side member main body 44. The second upper side member main body 45 includes an upper side member rear wall 57, a second upper side member flange 58 provided at a lower portion of the upper side member rear wall 57, and a second top flange 59 provided at an upper portion of the upper side member rear wall 57.

[0089] The upper side member rear wall 57 is arranged at the rear of the vehicle at a distance from the upper side member front wall 47. The upper side member rear wall 57 extends in the vehicle width direction and is connected to the extended portion 72 on the left outer side and the right outer side in the vehicle width direction (through Figure 3 、 Figure 7 described later) connection.

[0090] The second upper side member flange 58 is formed toward the vehicle rear from the lower side of the upper side member rear wall 57. The second top flange 59 is formed from the upper side of the upper side member rear wall 57 toward the vehicle front.

[0091] That is, the second upper panel body portion 45 is formed into a crank-shaped cross-section by the upper panel rear wall 57 , the second upper panel flange 58 , and the second top flange 59 .

[0092] The second top flange 59 of the second upper body 45 is connected from below to the first top flange 49. As a result, the first and second top flanges 49, 59 form an upper body top portion 61 of the upper body 41.

[0093] That is, the upper panel body 41 is formed into a substantially top-hat-shaped cross section by the upper panel front wall 47 , the upper panel rear wall 57 , the upper panel top 61 , the first upper panel flange 48 , and the second upper panel flange 58 .

[0094] like Figures 7 to 9 As shown, reinforcement members 42 are connected to the left and right ends of the first upper member body 44 on the vehicle widthwise outer side (specifically, the outer ends of the upper member front wall 47 and the outer ends of the first top flange 49). In other words, the upper surface of the vehicle widthwise outer end of the first upper beam 36 is formed by the reinforcement members 42, which are separate from the upper member body 41. It should be noted that the outer end of the upper member front wall 47 includes an inclined wall 52.

[0095] The reinforcement 42 includes a first reinforcement portion 65 and a second reinforcement portion 66 provided above the first reinforcement portion 65. The first reinforcement portion 65 is connected to the upper side member front wall 47 from the vehicle rear along the upper portion of the outer end portion thereof. The second reinforcement portion 66 is formed from the upper edge of the first reinforcement portion 65 toward the vehicle rear and is connected to the outer end portion of the first top flange 49 from below.

[0096] In this manner, the reinforcement member 42 is connected to the upper portion of the outer end of the upper member front wall 47 and the outer end of the first top flange 49, thereby forming the end upper surface portion (end upper surface) of the first upper beam 36. The reinforcement member 42 is designed to have higher strength and rigidity than the upper member body 41, for example, by making the plate thickness thicker than the upper member body 41 or using a material with higher strength and rigidity than the upper member body 41. Furthermore, the first reinforcement member portion 65 and the second reinforcement member portion 66 of the reinforcement member 42 are formed into a V-shaped cross-section. This further increases the strength and rigidity of the reinforcement member 42.

[0097] Here, the reinforcement rear end portion 66a of the second reinforcement portion 66, which is located on the vehicle rear side, extends outward from the outer end portion 49a of the first top flange 49. The outer end portion 49a of the first top flange 49 and the second reinforcement portion 66 form an upper side member top outer end portion 67 of the first upper member 36 continuously from the upper side member top portion 61 toward the vehicle width direction outer side.

[0098] <First lower beam>

[0099] like Figure 3 、 Figure 6 、 Figure 7 As shown, the first lower member 37 includes a lower side member central portion 71 and extended portions 72 provided at both ends of the lower side member central portion 71 in the vehicle width direction. The lower side member central portion 71 forms the vehicle width direction center portion of the first lower member 37. The lower side member central portion 71 is connected from below to the vehicle width direction center portion 36a of the first upper member 36 (hereinafter sometimes referred to as the upper side member central portion 36a).

[0100] Specifically, the lower side member central portion 71 has a central bottom 74 arranged at the lower part of the upper side member central portion 36a, a central rear wall 75 arranged at the rear of the vehicle of the central bottom 74, a first central flange 76 arranged at the front of the vehicle of the central bottom 74, and a second central flange 77 arranged at the upper part of the central rear wall 75.

[0101] The upper panel center portion 36a is disposed between the left and right upper panel outer ends 36b of the first upper member 36 in the vehicle width direction and is formed continuously with the upper panel outer ends 36b.

[0102] The center bottom portion 74 is disposed below the upper side member front wall 47 at the upper side member center portion 36a and is located opposite the upper side member top portion 61. A center rear wall 75 rises upward from the rear edge of the center bottom portion 74 and is spaced apart from the upper side member front wall 47 at the rear of the vehicle. A first center flange 76 extends from the front edge of the center bottom portion 74 toward the front of the vehicle. A second center flange 77 is formed from the upper edge of the center rear wall 75 toward the rear of the vehicle.

[0103] That is, the lower member center portion 71 is formed into a crank-shaped cross section by the center bottom portion 74 , the center rear wall 75 , the first center flange 76 , and the second center flange 77 .

[0104] In the lower panel center portion 71 , the first center flange 76 is connected from below to the first upper panel flange 48 of the upper panel center portion 36 a , and the second center flange 77 is connected from below to the second upper panel flange 58 of the upper panel center portion 36 a .

[0105] Thus, the vehicle width direction center portion 14A of the first floor cross member 14 (hereinafter sometimes referred to as cross member center portion 14A) is formed into a closed rectangular cross section by the upper side member center portion 36 a and the lower side member center portion 71 .

[0106] Extension portions 72 are connected to the left and right vehicle widthwise ends of the lower side member central portion 71. The extension portions 72 form the left and right vehicle widthwise lower side member ends of the first lower member 37.

[0107] The extension portion 72 has an extension bottom 81 arranged at the lower part of the outer end portion 51 of the front wall of the upper side member, an extension rear wall 82 arranged at the rear of the vehicle of the extension bottom 81, a first extension flange 83 arranged at the front of the vehicle of the extension bottom 81, and a second extension flange 84 arranged at the upper part of the extension rear wall 82.

[0108] The extended bottom portion 81 is disposed below the upper side member front wall outer end portion 51 (i.e., the inclined wall 52 and the outer front wall 53) and is positioned offset (displaced) toward the vehicle front side relative to the upper side member top outer end portion 67. The extended rear wall 82 rises from the rear edge of the extended bottom portion 81 in an upwardly inclined manner toward the vehicle rear.

[0109] The extended rear wall 82 is spaced apart from the upper side member front wall outer end 51 located on the vehicle front side and is disposed at the vehicle rear. A first extended flange 83 is formed from the front edge of the extended bottom portion 81 toward the vehicle front. A second extended flange 84 is formed from the upper edge of the extended rear wall 82 toward the vehicle rear.

[0110] The first extension flange 83 of the extension portion 72 is connected from below to the first upper flange 48 of the upper outer end portion 36b. The second extension flange 84 of the extension portion 72 is connected from below to the rear end of the upper top outer end portion 67 (specifically, the second reinforcement portion 66).

[0111] Therefore, the upper side member front wall outer end 51 , the upper side member top outer end 67 and the extension portion 72 form the widened portion 14B into a closed rhombus-shaped cross section at the left and right outer ends in the vehicle width direction of the first floor cross member 14 .

[0112] <Wide section>

[0113] like Figure 2 、 Figure 5As shown, the widened portion 14B is formed continuously with the left and right ends of the cross-member center portion 14A in the vehicle width direction. The left widened portion 14B, the right widened portion 14B, and the cross-member center portion 14A form the first floor cross-member 14. In other words, the first floor cross-member 14 includes the left widened portion 14B, the right widened portion 14B, and the cross-member center portion 14A.

[0114] Thus, the first floor cross member 14 is formed into a rectangular closed cross section continuous in the vehicle width direction by the left and right widened portions 14B and the cross member center portion 14A (in other words, the first upper member 36 and the first lower member 37). In other words, the first floor cross member 14 is a highly strong and rigid member that constitutes the vehicle body framework.

[0115] like Figures 8 to 10 As shown, the first floor cross member 14 is arranged to have a height H (see also FIG. 1 ) which increases toward the vehicle width direction outer side and toward the upper side (above the vehicle). Figure 6 、 Figure 7 ) is formed in an increasing manner, and the widened portion 14B is set to be the highest.

[0116] The widened portion 14B is provided, for example, from a position P1 overlapping with a battery module 121 described later in the vehicle longitudinal direction toward the vehicle width outer side, and the width W in the vehicle longitudinal direction (see also Figure 6 ) is wider than the central portion 14A of the beam.

[0117] Furthermore, a portion 14C (hereinafter sometimes referred to as the maximum widened portion 14C) of the widened portion 14B that overlaps with the front end 13b of the rear side frame 13 in the vehicle width direction has a vehicle longitudinal width W1 (also referred to as the maximum widened portion 14C). Figure 7 ) is set to maximum.

[0118] like Figure 3 、 Figure 7 、 Figure 9 As shown, the front end portion 13a of the rear side frame 13 is connected to the extended rear wall 82 of the widened portion 14B while contacting the extended rear wall 82 of the widened portion 14B. The connection between the extended rear wall 82 of the widened portion 14B and the front end portion 13a of the rear side frame 13 forms a boundary 88 between the widened portion 14B and the rear side frame 13. The boundary 88 is located at a position overlapping the battery module 121 (described later) in the vehicle front-to-rear direction (i.e., when viewed from the side) by an area E.

[0119] Here, the main portion 42a of the reinforcement member 42 is connected to the upper side member top outer end 67 of the widened portion 14B and the inclined wall 52. Furthermore, the inner end 42b of the reinforcement member 42 is connected to the upper side member front wall 47 and the first top flange 49 of the first upper side member main body 44, which are adjacent to the widened portion 14B. Thus, the inner end 42b of the reinforcement member 42 extends from the cross member end portion of the first floor cross member 14 on the vehicle width direction outer side (i.e., the outer end portion of the widened portion 14B) to a position further inboard of the widened portion 14B in the vehicle width direction.

[0120] <First and second ridgelines>

[0121] like Figure 9 、 Figure 10 As shown, the first floor cross member 14 has a first ridgeline (ridgeline) 92 and a second ridgeline (another ridgeline) 93 formed toward the vehicle front side relative to the first ridgeline 92. The first ridgeline 92 is formed by the intersection of the upper side member front wall 47 and the first top flange 49. The first ridgeline 92 has a first outer ridgeline 95 formed outboard in the vehicle width direction and a first center ridgeline 96 formed inboard of the first outer ridgeline 95 in the vehicle width direction.

[0122] The first outer ridgeline 95 is formed by the intersection of the inclined wall 52 of the upper side member front wall 47 and the outer end 49a of the first top flange 49 (i.e., the upper side member top 61). The first center side ridgeline 96 is formed by the intersection of the vehicle widthwise inner portion (center side front wall) 54 of the inclined wall 52 of the upper side member front wall 47 and the first top flange 49.

[0123] like Figure 8 、 Figure 10 As shown, the first outer ridgeline 95 is offset (displaced) toward the vehicle rear relative to the first central ridgeline 96. Furthermore, the first outer ridgeline 95 is offset toward the vehicle rear relative to the first central ridgeline 96 from the vehicle widthwise outer battery end 121a of the battery module 121, described later, located at the vehicle widthwise outer side. The first outer ridgeline 95 extends obliquely from the first central ridgeline 96 toward the vehicle rear and outward in the vehicle widthwise direction.

[0124] The second ridgeline 93 is formed by the intersection of the inclined wall 52 and the outer front wall 53. The second ridgeline 93 is located below the first outer ridgeline 95.

[0125] <Second floor beam>

[0126] like Figures 2 to 4 As shown, the second floor cross member 15 is arranged behind the vehicle relative to the power storage device 17 including the battery module 121 described later. The second floor cross member 15 extends in the vehicle width direction and is connected to the left rear side frame 13 and the right rear side frame 13.

[0127] Specifically, the second floor cross member 15 includes a second upper member 101 forming the upper portion of the second floor cross member 15 and a second lower member 102 forming the lower portion of the second floor cross member 15. The second upper member 101 also serves as a storage rear end portion 114 of the battery storage portion 16, which will be described later. The second lower member 102 is connected to the second upper member 101.

[0128] Specifically, if Figure 6 As shown, the second upper member 101 is formed into an L-shaped cross section by bending the upper corner portion 103 so as to protrude toward the vehicle front and upward. The second lower member 102 is formed into a substantially L-shaped cross section by bending the lower corner portion 106 so as to protrude toward the vehicle rear and downward.

[0129] The lower end 104 of the second upper member 101 is connected to the lower flange 107 of the second lower member 102. Furthermore, the rear flange 105 of the second upper member 101 is connected to the rear flange 108 of the second lower member 102. Thus, the second floor cross member 15 is formed into a rectangular closed cross section by the second upper member 101 and the second lower member 102. The second floor cross member 15 is a high-strength and high-rigidity member that constitutes the vehicle body framework. It should be noted that the front end of the rear floor panel 35 is connected to the rear flange 105 from above.

[0130] <Battery storage unit, power storage device>

[0131] like Figure 2 、 Figure 6 、 Figure 11 As shown, the battery storage section 16 is surrounded by the first floor cross member 14, the second floor cross member 15, the left rear side frame 13, and the right rear side frame 13. The battery storage section 16 houses the power storage device 17. Specifically, the battery storage section 16 includes a storage body 112, a storage front end 113 located at the vehicle front of the storage body 112, a storage rear end 114 located at the vehicle rear of the storage body 112, and storage ends 115 located at both ends of the storage body 112 in the vehicle width direction.

[0132] The storage body 112 includes a storage bottom 117, a storage rear wall 118 disposed at the vehicle rear of the storage bottom 117, and storage side walls (side walls) 119 disposed at both ends of the storage bottom 117 in the vehicle width direction. The storage bottom 117 is disposed substantially horizontally below the power storage device 17. A storage front end 113 extends from the front edge of the storage bottom 117 toward the vehicle front. The storage front end 113 is connected from above to the second upper member flange 58 of the first upper member 36 (i.e., the first floor cross member 14).

[0133] Furthermore, a storage rear wall 118 extends upward from the rear edge of the storage bottom 117. This wall is positioned on the vehicle rear side of the power storage device 17. A storage rear end portion 114 is formed on the upper edge of the storage rear wall 118. This rear end portion 114 also serves as the second upper member 101 of the second floor cross member 15. In other words, the storage rear wall 118 is connected to the second upper member 101 (the second floor cross member 15).

[0134] A left storage side wall 119 is formed upward at the left end of the storage bottom 117. The left storage side wall 119 is positioned on the left outer side in the vehicle width direction of the power storage device 17 (specifically, the battery outer end 121a of the battery module 121, described later, located on the outer side in the vehicle width direction). A left storage end 115 is formed on the upper side of the left storage side wall 119, facing outward in the vehicle width direction. Hereinafter, the left storage end 115 may be referred to simply as "storage end 115," and the left storage side wall 119 may be referred to simply as "storage side wall 119."

[0135] The rear end 115a of the receiving end portion 115 is connected to the left outer end (end) 114a of the receiving rear end portion 114 (i.e., the second floor cross member 15). Furthermore, the front end 115b of the receiving end portion 115 is connected from above to the reinforcement member 42 (i.e., the widened portion 14B). Furthermore, the receiving end portion 115 is connected from below to the frame front end portion 13a of the left rear side frame 13.

[0136] That is, the housing side wall 119 is connected to the widened portion 14B via the housing end portion 115 from the left outer end portion of the second floor cross member 15 toward the vehicle front.

[0137] The right storage end portion 115 and the right storage side wall 119 are formed substantially bilaterally symmetrically with the left storage end portion 115 and the left storage side wall 119. Therefore, detailed description of the right storage end portion 115 and the right storage side wall 119 is omitted.

[0138] In this manner, the outer periphery of the battery storage portion 16 is connected to the first floor cross member 14, the second floor cross member 15, the left rear side frame 13, and the right rear side frame 13. In the battery storage portion 16, an electric storage device 17 is housed (arranged).

[0139] The power storage device 17 includes, for example, a battery module 121, a blower fan (not shown), a high-voltage terminal block 122, and an ECU (Electronic Control Unit) 123. The battery module 121 includes, for example, a plurality of battery cells 124. Each battery cell 124 is formed, for example, by stacking multiple battery cells (not shown) in the vehicle width direction. Hereinafter, the battery module 121 may also be referred to simply as "battery 121."

[0140] Battery cover

[0141] like Figure 1 、 Figure 12 As shown, the opening 16a of the battery storage portion 16 is covered from above by a battery cover 18. The battery cover 18 is a metal cover formed of a metal material so as to cover the upper portion of the power storage device 17. The battery cover 18 is connected to the first floor cross member 14 and the second floor cross member 15.

[0142] Specifically, the battery cover 18 has a cover body 131 located above the battery device 17, a front connecting portion 132 provided at the front end of the cover body 131 in the vehicle front-rear direction, a rear connecting portion 133 provided at the rear end of the cover body 131 in the vehicle front-rear direction, and vehicle width outer side connecting portions (vehicle width outer side connecting portions) 134 provided at both ends of the cover body 131 in the vehicle width direction.

[0143] It should be noted that the left and right vehicle width outer connecting portions 134 are substantially bilaterally symmetrical. Therefore, the left vehicle width outer connecting portion 134 will be simply referred to as the "vehicle width outer connecting portion 134" in detail below, and the description of the right vehicle width outer connecting portion 134 will be omitted.

[0144] The cover body 131 bulges upward from the power storage device 17. The front connecting portion 132 is fixed (connected) to the upper front wall 47 of the first floor cross member 14 by fastening with fastening members such as bolts 141 and nuts (not shown).

[0145] The rear connecting portion 133 is fastened to (connected to) the second upper beam 101 of the second floor cross member 15 by fastening members such as bolts and nuts (both not shown).

[0146] like Figure 7 、 Figure 12 、 Figure 13 As shown, the vehicle width outer side connection portion 134 is formed at the left end portion (i.e., the outer end portion) of the cover body 131 on the left outer side (vehicle width direction outer side) in the vehicle width direction. The vehicle width outer side connection portion 134 straddles the inclined wall 52 in the vehicle front-to-back direction. Specifically, the vehicle width outer side connection portion 134 includes a front side fixing portion (front side connection portion) 136 fixed to the upper side member front wall 47 and a rear side fixing portion (rear side connection portion) 137 extending from the upper portion of the front side fixing portion 136 toward the rear of the vehicle.

[0147] The front fixing portion 136 is fastened (connected) to a portion of the upper front wall 47 located below the inclined wall 52 (ie, the outer front wall 53 ) by fastening with fastening members such as bolts 145 and nuts 146 .

[0148] The rear fixing portion 137 is connected to a position where three members, namely, the upper frame front end portion 28a of the rear frame upper member 28, the second reinforcement portion 66 of the first upper beam 36, and the second extended flange 84 of the first lower beam 37, overlap in the vertical direction. Specifically, the rear fixing portion 137 is fastened (connected) to the upper frame front end portion 28a, the second reinforcement portion 66, and the second extended flange 84 by fastening members such as bolts 147 and nuts 148.

[0149] As described above, the vehicle body rear structure 10 of the embodiment can achieve the following functions and effects. It should be noted that the left side structure of the vehicle body will be described in detail below, and the detailed description of the right side structure will be omitted.

[0150] like Figure 7 、 Figure 8 As shown, the boundary 88 between the widened portion 14B of the first floor cross member 14 and the rear side frame 13 is positioned so as to overlap with the battery 121 in region E when viewed from the side. Therefore, the boundary 88 can support a load F1 (hereinafter sometimes referred to as the side collision load F1) applied from the vehicle widthwise outer side of the battery 121, for example, in a side collision. This effectively transfers the side collision load F1 from the boundary 88 to the vehicle widthwise center of the first floor cross member 14, allowing the first floor cross member 14 to absorb the side collision load F1.

[0151] This reduces deformation of the vehicle body's side portions (e.g., the widened portion 14B, the rear side frames 13, and the rocker 12) located outboard of the battery 121 in the vehicle width direction, thereby preventing damage (deformation) to the battery 121 and protecting it. By positioning the boundary 88 between the widened portion 14B and the rear side frames 13 so that it overlaps with the battery 121, the side impact load F1 can be absorbed by the first floor cross member 14, without requiring reinforcement of the rear side frames 13 with reinforcement members. Consequently, the vehicle body can be lightweighted.

[0152] Here, if an excessive side impact load F2 is input, for example, due to a side collision, the widened portion 14B (i.e., the first floor cross member 14) may bend toward the rear side frame 13. Meanwhile, the widened portion 14B contacts the rear side frame 13 by forming a boundary portion 88 with the rear side frame 13. Therefore, if an excessive side impact load F2 is input, for example, due to a side collision, the widened portion 14B can be supported by the rear side frame 13 to prevent the widened portion 14B from bending (collapse).

[0153] As a result, the rear side frame 13 can suppress the widened portion 14B from bending toward the rear side frame 13 (i.e., toward the battery 121) due to excessive side collision loads F2, allowing the excessive side collision loads F2 to be transmitted toward the center of the first floor cross member 14. Furthermore, by suppressing the collapse of the widened portion 14B, the widened portion 14B can be appropriately deformed by the excessive side collision loads F2, thereby absorbing the impact energy caused by the excessive side collision loads F2. Consequently, even in the face of excessive side collision loads F2, damage (deformation) to the battery 121 can be suppressed, protecting the battery 121.

[0154] In addition, if Figure 7 、 Figure 10 As shown, an inclined wall 52 is formed on the front surface of the widened portion 14B. Thus, for example, the intersection of the inclined wall 52 and the outer front wall 53 on the front surface of the widened portion 14B forms a V-shape that protrudes toward the front of the vehicle. Specifically, this intersection forms a second ridgeline (ridgeline) 93 extending generally in the vehicle width direction. This increases the ridgeline of the first floor cross member 14. Consequently, the side impact load F1 input to the end of the first floor cross member 14 (i.e., the widened portion 14B) can be efficiently transferred toward the center of the first floor cross member 14.

[0155] Furthermore, the side collision load F1 can also be transmitted to the front floor panel 22 provided on the vehicle front side of the first floor cross member 14 .

[0156] For example, the end portion (widened portion 14B) of the first floor cross member 14 is located at the rear lower portion of the opening for the rear door. Therefore, by forming an inclined wall 52 on the front surface of the widened portion 14B, a large amount of foot space can be secured on the outer side of the vehicle width direction within the vehicle cabin. This makes it easier for passengers to enter and exit the vehicle cabin.

[0157] Moreover, if Figure 9 、 Figure 10 As shown, the first outer ridgeline 95 of the first ridgeline 92 of the first floor cross member 14, located on the side of the inclined wall 52 (i.e., the widened portion 14B), is offset toward the vehicle rear relative to the first center-side ridgeline 96 located toward the center in the vehicle width direction. This allows the first outer ridgeline 95 to be positioned closer to the battery 121 in the vehicle longitudinal direction. Consequently, a side impact load F1, such as that caused by a side collision and input from the vehicle width direction outward of the battery 121, can be efficiently transmitted to the first center-side ridgeline 96 while being received by the first outer ridgeline 95. In other words, the side impact load F1 can be efficiently transmitted toward the center of the first floor cross member 14.

[0158] In addition, if Figure 8 、 Figure 10As shown, the second ridgeline 93 is formed below the first outer ridgeline 95. Therefore, the first outer ridgeline 95 and the second ridgeline 93 can bear the side impact load F1, which is input from the vehicle widthwise outer side of the battery 121, for example, in a side collision. This allows the side impact load F1 to be more efficiently transmitted toward the center of the first floor cross member 14.

[0159] In addition, if Figure 7 、 Figure 8 As shown, the maximum widened portion 14C of the widened portion 14B is formed so as to overlap with the front end 13b of the rear side frame 13 in the vehicle width direction, and the vehicle longitudinal width W1 of the maximum widened portion 14C is set to be the largest in the widened portion 14B. Therefore, for example, the widened portion 14B can be brought into contact with or close to the front end 13b of the rear side frame 13 in the vehicle longitudinal direction.

[0160] Thus, the rear side frame 13 can suppress bending (collapse) of the widened portion 14B toward the rear side frame 13 due to the side collision load F1. Therefore, the side collision load F1 can be efficiently transmitted to the center of the first floor cross member 14, and the first floor cross member 14 can absorb the side collision load F1.

[0161] Furthermore, even when an excessive side impact load F2 is input, such as in a side collision, the rear side frame 13 can suppress the collapse of the widened portion 14B toward the rear side frame 13 due to the side impact load F2. Therefore, the excessive side impact load F2 can be efficiently transmitted toward the center of the first floor cross member 14. Furthermore, by suppressing the collapse of the widened portion 14B, the excessive side impact load F2 can be applied to the widened portion 14B (particularly the maximum widened portion 14C), thereby absorbing the impact energy caused by the excessive side impact load F2.

[0162] In addition, if Figure 2 、 Figure 11 As shown, the battery storage portion 16 is formed so as to be surrounded by the first floor cross member 14, the second floor cross member 15, the left rear side frame 13, and the right rear side frame 13. A battery 121 is arranged in the battery storage portion 16, and the storage side wall 119 of the battery storage portion 16 is connected to the widened portion 14B via the storage end portion 115 from the left outer end 114a of the second floor cross member 15 toward the vehicle front.

[0163] Therefore, for example, the side collision load F1 input to the widened portion 14B can be transmitted to the first floor cross member 14 and then to the second floor cross member 15 via the storage side wall 119 of the battery storage portion 16 .

[0164] In other words, the side collision load F1 can be efficiently transmitted to the first floor cross member 14 and the second floor cross member 15. As a result, the side collision load F1 can be supported by the first floor cross member 14 and the second floor cross member 15. Consequently, deformation of the vehicle body side portions (e.g., the widened portion 14B, the rear side frame 13, the rocker 12, etc.) located outboard of the battery 121 in the vehicle width direction can be suppressed, thereby preventing damage (deformation) to the battery 121 and protecting it.

[0165] Moreover, if Figure 7 、 Figure 9 、 Figure 10 As shown, the height H of the widened portion 14B of the first floor cross member 14 is set to the maximum. This ensures a large cross-sectional area for the widened portion 14B, improving strength and rigidity. Consequently, the widened portion 14B can be appropriately deformed by the side collision load F1, absorbing the impact energy caused by the side collision load F1. This prevents damage (deformation) to the battery 121 caused by the side collision load F1, protecting the battery.

[0166] Furthermore, the first floor cross member 14 is formed so that the height H increases toward the upper side of the vehicle as it goes toward the outer side in the vehicle width direction. Therefore, in the first floor cross member 14, the height H of the cross member center portion 14A located inward in the vehicle width direction relative to the widened portion 14B can be increased (see also FIG. Figure 6 ) is suppressed to be lower than the height H of the widened portion 14B. Thus, a space for passing the wiring of the battery 121 can be ensured in the beam center portion 14A.

[0167] In addition, if Figure 1 、 Figure 12 As shown, the metal battery cover 18 covering the upper portion of the battery 121 is connected to the first floor cross member 14 and the second floor cross member 15. In addition, the vehicle width outer side connection portion 134 of the battery cover 18 is connected across the inclined wall 52 (see also Figure 7 By making the battery cover 18 from metal, the strength and rigidity of the battery cover 18 can be increased. Therefore, the inclined wall 52 of the widened portion 14B can be reinforced by the highly strong and rigid vehicle width outer connecting portion 134, thereby increasing the strength and rigidity of the inclined wall 52 (i.e., the first floor cross member 14).

[0168] Thus, the side collision load F1 can be transmitted to the metal battery cover 18 via the widened portion 14B and the vehicle widthwise outer connecting portion 134, and the side collision load F1 can be supported by the battery cover 18. Consequently, deformation of the first floor cross member 14 caused by the side collision load F1 can be suppressed, and damage (deformation) to the battery 121 can be suppressed, thereby protecting the battery 121.

[0169] In addition, if Figure 12 、 Figure 13 As shown, the rear fixing portion 137 of the vehicle widthwise outer connecting portion 134 of the battery cover 18 is fastened to the rear side frame 13 (upper side member frame front end portion 28a) using, for example, bolts 147 and nuts 148. The rear side frame 13 is connected to the second floor cross member 15. Thus, the first floor cross member 14, the rear side frame 13, and the second floor cross member 15 can be connected via the battery cover 18.

[0170] Thus, the side collision load F1 can be transmitted to the battery peripheral components composed of the first floor cross member 14, the rear side frame 13, the second floor cross member 15 and the battery cover 18. Therefore, the battery 121 (see FIG. 1 ) can be improved in terms of the side collision load F1. Figure 10 ) can improve the strength and rigidity of the surrounding components, thereby suppressing damage (deformation) of the battery 121 and protecting the battery 121.

[0171] Here, the upper side member frame front end portion 28a of the rear side frame upper side member 28, the second reinforcement portion 66 of the first upper beam 36, and the second extended flange 84 of the first lower beam 37 overlap in the vertical direction. The rear side fixing portion 137 of the vehicle widthwise outer side connecting portion 134 is fastened and connected from above to the position where the upper side member frame front end portion 28a, the second reinforcement portion 66, and the second extended flange 84 overlap, for example, using bolts 147, nuts 148, etc.

[0172] Therefore, the four members of the rear fixing portion 137, the rear frame upper member 28, the first upper beam, and the first lower beam can be overlapped and connected, for example, by bolts 147 and nuts 148. This improves the strength and rigidity of the connection portion 154 where the four members are overlapped and connected, and improves the efficiency of transmitting the side collision load F1.

[0173] Therefore, the side collision load F1 can be efficiently distributed and transmitted to the four members of the rear fixing portion 137 (i.e., the battery cover), the rear frame upper member 28, the first upper beam 36, and the first lower beam 37. Figure 10 ) to protect the battery 121.

[0174] Furthermore, by overlapping and connecting the four components, namely, the rear fixing portion 137, the rear frame upper member 28, the first upper beam 36, and the first lower beam 37, the strength and rigidity of the connection portion 154 of the four components can be improved. Thus, the connection portion 154 of the four components can support loads input from, for example, a rear seat (not shown) disposed above the battery cover 18, thereby improving the riding comfort of passengers seated in the seat.

[0175] In addition, if Figure 9 、 Figure 12 , Figure 13 As shown, the upper surface of the end portion of the first upper beam 36 on the outside in the vehicle width direction is formed by a reinforcement member 42 that is a separate body from the upper side member main body 41. Furthermore, the strength and rigidity of the reinforcement member 42 are set higher than those of the upper side member main body 41. Furthermore, the inner end portion 42b of the reinforcement member 42 extends to a position further inward in the vehicle width direction than the widened portion 14B. Therefore, the upper surface of the end portion of the first upper beam 36 on the outside in the vehicle width direction is set higher in strength and rigidity due to the reinforcement member 42. The upper surface of the end portion of the first upper beam 36 is included in the widened portion 14B. This allows the strength and rigidity of the widened portion 14B to be set higher.

[0176] Furthermore, the reinforcement member 42 of the first upper beam 36 overlaps and connects three components: the rear fixing portion 137 of the battery cover 18, the rear frame upper member 28, and the first lower beam 37, forming a connection portion 154 together with these three components. This further enhances the strength and rigidity of the connection portion 154 formed by the four components, thereby increasing the rigidity of the connection between the rear frame 13 and the battery cover 18.

[0177] By setting the strength and rigidity of the widened portion high and increasing the connection rigidity between the rear side frame 13 and the battery cover 18 in this manner, it is possible to improve the protection performance of the battery 121 against, for example, the side collision load F1.

[0178] Furthermore, the upper surface of the end portion of the first upper beam 36 is formed by a reinforcement member 42 that is separate from the upper member main body 41. Thus, for example, by selecting a different reinforcement member corresponding to a different model, the upper member main body 41 can be shared across different models. Thus, by selecting reinforcement members corresponding to different models, the upper member main body 41 and the first lower beam 37, which constitute the main portion of the first floor cross member, can be shared across different models.

[0179] It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0180] For example, in the above embodiment, the fixing portions 136 and 137 are fixed (connected) by being fastened together using fastening members such as bolts 145 and 147 and nuts 146 and 148. However, the present invention is not limited to this, and various fixing members can be used to fix the fixing portions 136 and 137. For example, screws or the like can be used instead of the bolts 145 and 147 and nuts 146 and 148.

[0181] Furthermore, components in the above-described embodiments may be appropriately replaced with well-known components without departing from the spirit of the present invention, and the above-described modifications may be appropriately combined.

Claims

1. A vehicle body rear structure comprising: a first floor cross member disposed in front of the vehicle relative to the battery and connected to a rear side frame extending in the vehicle front-rear direction on an outer side in the vehicle width direction; and a second floor cross member disposed at the rear of the vehicle relative to the battery; The rear vehicle body structure is characterized in that: The first floor cross member includes a widened portion at an end portion, wherein the width of the widened portion in the vehicle front-rear direction is widened to a position overlapping with the battery. A boundary portion between the widened portion and the rear side frame is arranged at a position overlapping with the battery in a side view.

2. The vehicle body rear structure according to claim 1, characterized in that: The widened portion has an inclined surface on a front surface located on the vehicle front side, the inclined surface being inclined upward toward the vehicle rear.

3. The vehicle body rear structure according to claim 2, characterized in that: The first floor cross member has a ridge line formed by an intersection of the front surface and a top portion formed from the front surface toward the rear of the vehicle. The ridgeline has: a first outer ridgeline formed by the intersection of the inclined surface and the top; and a first central side ridgeline formed by an intersection of a portion of the front surface located inside the inclined surface in the vehicle width direction and the top portion; The first outer ridgeline is offset toward the vehicle rear relative to the first center ridgeline.

4. The vehicle body rear structure according to claim 3, characterized in that: The first outer ridgeline is offset toward the rear of the vehicle relative to the first center ridgeline, starting from the outer end of the battery in the vehicle width direction. The first floor cross member has another ridgeline formed by an intersection of the inclined surface of the front surface and another surface below the inclined surface, and is located below the first outer ridgeline.

5. The vehicle body rear structure according to claim 3, characterized in that: The vehicle front-rear direction width of a portion of the widened portion that overlaps with the rear side frame in the vehicle width direction is set to be maximum.

6. The vehicle body rear structure according to claim 2, characterized in that: The vehicle body rear structure includes a storage portion surrounded by the first floor cross member, the second floor cross member, and the rear side frame, in which the battery is disposed. The housing portion includes a side wall connected to the widened portion from an end portion of the second floor cross member.

7. The vehicle body rear structure according to claim 1, wherein: The first floor cross member is formed so that its height increases toward the upper side of the vehicle as it goes outward in the vehicle width direction, and the widened portion is set to be the highest.

8. The vehicle body rear structure according to claim 5, characterized in that: The vehicle body rear structure includes a metal battery cover connected to the first floor cross member and the second floor cross member and covering an upper portion of the battery. The battery cover has a vehicle width outer side connection portion at a cover outer side end portion on the vehicle width outer side, which is connected across the inclined surface in the vehicle front-rear direction. The vehicle width outer side connection portion has: a rear fixing portion connected to the rear frame; and A front fixing portion is connected to a portion below the inclined surface of the first floor cross member at the front surface located on the vehicle front side.

9. The vehicle body rear structure according to claim 8, characterized in that: The first floor beam comprises: a first floor beam upper side member formed by the front surface and the top portion; and The first floor crossbeam lower side member is connected to the first floor crossbeam upper side member, The rear side frame includes a rear side frame upper side member that closes the upper opening. The rear fixing portion is connected to a position where the rear frame upper member, the first floor cross member upper member, and the first floor cross member lower member overlap in a vertical direction.

10. The vehicle body rear structure according to claim 9, characterized in that: The first floor beam upper side member comprises: an upper member body forming a major portion of the first floor cross member upper member; and a reinforcement member connected to the outer end portion in the vehicle width direction of the upper member main body and forming the upper end surface of the first floor cross member upper member; The rigidity of the reinforcement member is set higher than the rigidity of the upper member body. The inner end portion of the reinforcement member on the inner side in the vehicle width direction extends from the outer cross member end portion of the first floor cross member in the vehicle width direction to a position further inward in the vehicle width direction than the widened portion.

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