Vehicle body structure

Abstract

The invention provides a vehicle body structure capable of improving load absorption efficiency based on a side frame and a panel and further contributing to sustainable development of a conveying system. A vehicle body structure (Ve) is provided with: an upper panel (17) and a lower panel (18); and a left rear frame (14) and a right rear frame (15) which are connected to the outer sides of the panels (17, 18) in the vehicle width direction and which extend in the front-rear direction of the vehicle. The left rear frame (14) has a first rigidity change region (31) and a second rigidity change region (32). The first rigidity change region (31) and the second rigidity change region (32) are provided on the inner side surface (21) and the outer side surface (22) of the left rear frame (14). The second rigidity change region (32) is provided at a different position in the longitudinal direction from the first rigidity change region (31).

Description

Technical Field

[0001] The present invention relates to a vehicle body structure. Background Art

[0002] In recent years, efforts to provide access to sustainable transportation systems have intensified. To achieve this goal, research and development efforts are underway to further improve traffic safety and convenience through improvements in vehicle body rigidity. For example, a known vehicle body structure includes side frames positioned on the left and right sides of the panel in the vehicle width direction, with the side frames extending in the vehicle's longitudinal direction.

[0003] The side frame includes a side frame body and an upper wall member disposed above the side frame body. Multiple fragile portions are formed at intervals along the longitudinal direction (vehicle front-to-back direction) of the lower portion of the side frame body. The upper wall member is provided with a bending starting point. With this vehicle body structure, when an impact load is input from the front and rear of the vehicle, the fragile portions and the bending starting point deform the side frame, bending in the vertical direction, thereby absorbing the impact load (see, for example, Japanese Patent Application Laid-Open No. 2021-160412). Summary of the Invention

[0004] In the above-mentioned prior art, since the side frames are deformed in the vertical direction to absorb the impact load, it is difficult to fully deform the panel in conjunction with the side frames. Therefore, there is room for improvement in improving the load absorption efficiency by fully deforming the panel in conjunction with the side frames.

[0005] An object of the present invention is to provide a vehicle body structure that can improve the load absorption efficiency of side frames and panels and thereby contribute to the development of a sustainable transportation system.

[0006] (1) A vehicle body structure according to one embodiment of the present invention comprises: a panel disposed below a vehicle; and a side frame connected to the outer side of the panel in the vehicle width direction and extending in the vehicle front-rear direction, the side frame having a plurality of rigidity change regions, the plurality of rigidity change regions being disposed on the outer side and the inner side of the side frame in the vehicle width direction, the rigidity change regions disposed on the outer side in the vehicle width direction being disposed at different positions in the longitudinal direction relative to the rigidity change regions disposed on the inner side in the vehicle width direction.

[0007] This configuration provides rigidity-variable regions on the vehicle widthwise outer and inner sides of the side frames. Therefore, when an impact load is applied to the side frames from the vehicle's longitudinal direction, the side frames can bend outward and inward in the vehicle widthwise direction, starting from the rigidity-variable regions. This bending deformation of the side frames absorbs the impact load.

[0008] Here, the panel is connected to the side frame. Therefore, by bending the side frame outward and inward in the vehicle width direction, starting from the rigidity change region, loads are transferred from the side frame to the panel. Specifically, loads compressing the panel inward in the vehicle width direction and loads stretching the panel outward in the vehicle width direction are transferred from the side frame to the panel. Furthermore, loads causing the panel to deform in the vehicle front-rear direction are transferred from the side frame to the panel. This allows for efficient load transfer across the entire panel area, enabling appropriate deformation across the entire panel area.

[0009] Furthermore, the outer and inner rigidity varying regions in the vehicle width direction are located at different positions in the longitudinal direction of the side frame. This prevents stress from concentrating on a single portion of the side frame, and allows the side frame to deform in an appropriately curved manner, starting from the rigidity varying region.

[0010] By appropriately deforming the side frames and the entire panel in this manner, the load absorption efficiency of the side frames and the panel can be improved, thereby contributing to the development of a sustainable transportation system.

[0011] (2) In the above aspect, the side frame may be provided with fragile portions continuous in the vehicle width direction on the vehicle upper side and the vehicle lower side.

[0012] This configuration allows the fragile portion to deform together with the outer and inner rigidity change regions in the vehicle width direction, thereby further appropriately promoting deformation of the side frame in the vehicle width direction, whereby bending occurs starting from the rigidity change region.

[0013] Furthermore, the side frame can be prevented from buckling due to stress concentration, allowing it to be appropriately bent in the vehicle width direction starting from the rigidity change region. This allows the load to be appropriately distributed (transmitted) across the entire panel area. This distributed load can then be used to appropriately deform the entire panel area.

[0014] (3) In the above embodiment, the side frame may be provided at the rear of the vehicle, and the plurality of rigidity change regions may be provided at positions close to rear ends of the side frames.

[0015] With this configuration, when an impact load is input from the rear of the vehicle, the rear end portion of the side frame is deformed so as to bend outward and inward in the vehicle width direction, thereby absorbing the load.

[0016] By bending the rear end portions of the side frames outward and inward in the vehicle width direction, load is transmitted from the rear end portions of the side frames to the rear end portions of the panel.

[0017] Specifically, loads compressing the rear end of the panel inward in the vehicle width direction and loads stretching the rear end of the panel outward in the vehicle width direction are transmitted from the rear end of the side frame to the rear end of the panel. Furthermore, loads deforming the rear end of the panel toward the front of the vehicle are transmitted from the rear end of the side frame to the panel. This allows loads to be efficiently transferred from the rear end of the panel to the entire panel area.

[0018] Furthermore, by providing multiple rigidity-changing regions at the rear ends of the side frames, when an impact load is input from the rear of the vehicle, the rear ends of the side frames can be bent in the vehicle width direction before the panel significantly deforms toward the front of the vehicle. This allows the side frames to absorb the impact load while efficiently transmitting the load to the entire panel area.

[0019] As a result, the impact load can be absorbed by the side frames, and the load can be appropriately distributed over the entire area of ​​the wide panel, thereby improving the load absorption efficiency of the panel.

[0020] (4) In the above embodiment, the side frame may be provided at the front of the vehicle, and the plurality of rigidity change regions may be provided at positions close to the front end portions of the side frames.

[0021] With this configuration, when an impact load is input from the front of the vehicle, the front end portion of the side frame is deformed so as to bend outward and inward in the vehicle width direction, thereby absorbing the load.

[0022] By bending the front end side of the side frame outward and inward in the vehicle width direction, the load is transmitted from the front end side of the side frame to the front end side of the panel.

[0023] Specifically, loads compressing the front end of the panel inward in the vehicle width direction and loads stretching the front end of the panel outward in the vehicle width direction are transmitted from the front end of the side frame to the front end of the panel. Furthermore, loads deforming the front end of the panel toward the rear of the vehicle are transmitted from the front end of the side frame to the panel. This allows loads to be efficiently transferred from the front end of the panel to the entire panel area.

[0024] Furthermore, by providing multiple rigidity-changing regions at the front ends of the side frames, when an impact load is input from the front of the vehicle, the front ends of the side frames can bend in the vehicle width direction before the panels significantly deform toward the rear. This allows the side frames to absorb the impact load while efficiently transmitting the load to the entire panel area.

[0025] As a result, the impact load can be absorbed by the side frames, and the load can be appropriately distributed over the entire area of ​​the wide panel, thereby improving the load absorption efficiency of the panel.

[0026] (5) In the above embodiment, the fragile portion and the rigidity change region may be provided at positions overlapping with each other in the vehicle front-rear direction.

[0027] With this configuration, the fragile portion deforms under the impact load input to the side frame from the vehicle front-rear direction, thereby promoting deformation of the side frame in the vehicle front-rear direction.

[0028] Here, the fragile portion is located at a position that overlaps (intersects) the rigidity varying region in the vehicle longitudinal direction. This prevents stress concentration in the rigidity varying regions located at different positions along the longitudinal direction of the side frame. By suppressing stress concentration in the rigidity varying regions located at different positions, buckling of the side frame in the vehicle longitudinal direction can be suppressed.

[0029] Therefore, the side frame can be reliably bent outward and inward in the vehicle width direction starting from the rigidity change region. As a result, the load that compresses the panel inward in the vehicle width direction and the load that pulls the panel outward in the vehicle width direction can be reliably transmitted from the side frame to the panel.

[0030] According to the solution of the present invention, the load absorption efficiency based on the side frames and panels can be improved, and the solution of the present invention further contributes to the development of a sustainable transportation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a perspective view of the vehicle body structure according to the embodiment of the present invention as viewed from the left side of the front of the vehicle.

[0032] Figure 2 This is a side view of the vehicle body structure according to the embodiment of the present invention as viewed from the left side in the vehicle width direction.

[0033] Figure 3 This is a perspective view of the left rear side frame of the vehicle body structure according to the embodiment of the present invention as viewed from the front left side of the vehicle.

[0034] Figure 4 This is a plan view of the left rear side frame of the vehicle body structure according to the embodiment of the present invention as viewed from above.

[0035] Figure 5 This is a plan view illustrating the transmission of an impact load input from the rear of the vehicle to a rear floor structure of a vehicle body structure in an embodiment of the present invention.

[0036] Figure 6 This is a plan view illustrating a front floor structure according to a modified example of the embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, a vehicle body structure according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, arrow FR indicates the front of the vehicle, arrow UP indicates the upper direction of the vehicle, and arrow LH indicates the left side of the vehicle.

[0038] Figure 1 This is a perspective view of the vehicle body structure as viewed from the left side of the front of the vehicle. Figure 2 This is a side view of the vehicle body structure as viewed from the left side in the vehicle width direction.

[0039] <Body structure>

[0040] like Figure 1 、 Figure 2 As shown, the vehicle body structure Ve includes a rear floor structure 10 below a rear trunk 12 at the rear of the vehicle. The rear floor structure 10 includes, for example, a left rear side frame (side frame) 14 and a right rear side frame (side frame) 15 arranged on both sides in the vehicle width direction, a rear bumper beam 16 spanned across the rear end portions 14b and 15b of the rear side frames 14 and 15, an upper panel (panel) 17 provided on the upper surfaces 23 and 28 of the rear side frames 14 and 15, and a lower panel (panel) 18 provided on the lower surfaces 24 and 29 of the rear side frames 14 and 15.

[0041] The left rear side frame 14 is provided at a lower portion on the left side in the vehicle width direction of the rear trunk 12. The left rear side frame 14 extends toward the rear of the vehicle from a front end portion 14a toward a rear end portion 14b in the vehicle front-rear direction.

[0042] The left rear side frame 14 has an inner side surface 21 located inward in the vehicle width direction, an outer side surface 22 located outward in the vehicle width direction, an upper surface 23 located above the vehicle, and a lower surface 24 located below the vehicle. Specifically, the inner side surface 21 and the outer side surface 22 are formed so as not to extend along the entire circumference of the left rear side frame 14, separated from each other inward and outward in the vehicle width direction. The left rear side frame 14 is formed into a hollow shape with a rectangular cross-section by the inner side surface 21, the outer side surface 22, the upper surface 23, and the lower surface 24.

[0043] The right rear frame 15 is provided at the lower portion of the rear trunk 12 on the right side in the vehicle width direction. The right rear frame 15 extends rearward of the vehicle from a front end 15a to a rear end 15b in the vehicle longitudinal direction. In other words, the right rear frame 15 extends rearward of the vehicle along the left rear frame 14.

[0044] The right rear side frame 15 has an inner side surface 26 located inward in the vehicle width direction, an outer side surface 27 located outward in the vehicle width direction, an upper surface 28 located above the vehicle, and a lower surface 29 located below the vehicle. Specifically, the inner side surface 26 and the outer side surface 27 are formed so as not to extend along the entire circumference of the right rear side frame 15, separated from each other inward and outward in the vehicle width direction. The right rear side frame 15 is formed into a hollow shape with a rectangular cross-section by the inner side surface 26, the outer side surface 27, the upper surface 28, and the lower surface 29.

[0045] In this embodiment, the left and right rear frames 14 and 15 are described as rectangular hollow bodies, but the present invention is not limited to this. As another example, the left and right rear frames can be formed into rectangular hollow bodies by using a frame member with an open top and a U-shaped cross-section and an upper frame portion that closes the upper portion of the frame member. Alternatively, the left and right rear frames 14 and 15 can be formed into circular hollow bodies.

[0046] The rear bumper beam 16 extends in the vehicle width direction. The left rear side frame 14, the right rear side frame 15, and the rear bumper beam 16 are highly rigid members constituting the framework of the vehicle body structure Ve (specifically, the rear floor structure 10).

[0047] The upper panel 17 and lower panel 18 are disposed below the rear trunk 12 (below the vehicle) and form the floor of the rear trunk 12. Specifically, the upper panel 17 is formed from a plate having a generally rectangular shape when viewed from above. The left outer side (outer side) 17a of the upper panel 17 in the vehicle width direction is connected to the upper surface 23 of the left rear side frame 14 from above the vehicle. The right outer side (outer side) 17b of the upper panel 17 in the vehicle width direction is connected to the upper surface 28 of the right rear side frame 15 from above the vehicle.

[0048] The lower panel 18 is formed of a plate having a generally rectangular shape when viewed from above. A left outer portion (outer portion in the vehicle width direction) 18a of the lower panel 18 is connected from below the vehicle to the lower surface 24 of the left rear side frame 14. A right outer portion (outer portion in the vehicle width direction) 18b of the lower panel 18 is connected from below the vehicle to the lower surface 29 of the right rear side frame 15.

[0049] Specifically, the left rear side frame 14 extends in the vehicle longitudinal direction while being connected to the vehicle lower and vehicle width direction left outer side 17a of the upper panel 17 and to the vehicle upper and vehicle width direction left outer side 18a of the lower panel 18 .

[0050] The right rear side frame 15 extends in the vehicle longitudinal direction while being connected to the vehicle lower and vehicle width direction right outer side portion 17 b of the upper panel 17 and to the vehicle upper and vehicle width direction right outer side portion 18 b of the lower panel 18 .

[0051] In this embodiment, the rear floor structure 10 is described as including the upper panel 17 and the lower panel 18, but the present invention is not limited thereto. Alternatively, only the upper panel 17 may be connected to the upper surface 23 of the left rear side frame 14 and the upper surface 28 of the right rear side frame 15. Alternatively, only the lower panel 18 may be connected to the lower surface 24 of the left rear side frame 14 and the lower surface 29 of the right rear side frame 15.

[0052] <Rear side frame>

[0053] Figure 3 This is a perspective view of the left rear side frame of the vehicle body structure as viewed from the front left side of the vehicle. Figure 4 This is a top view of the left rear side frame of the vehicle body structure as seen from above.

[0054] The left rear side frame 14 has multiple rigidity varying regions 31 and 32 and multiple fragile portions 41 to 46. In this embodiment, two rigidity varying regions 31 and 32 are exemplified: a first rigidity varying region 31 and a second rigidity varying region 32. The rigidity varying regions are not limited to two and can be selected arbitrarily.

[0055] The first and second rigidity varying regions 31, 32 are provided in the rear portion 14c, on the rear end portion 14b side of the left rear side frame 14. The rear portion 14c is located further rearward of the vehicle than the center of the left rear side frame 14 in the vehicle front-to-rear direction, and is close to the rear end portion 14b of the left rear side frame 14. "Close to the rear end portion 14b" means that the rear portion 14c may not be in complete contact with the rear end portion 14b. In this embodiment, the rear portion 14c is described as extending from the rear end portion 14b to a position spaced a predetermined distance forward of the vehicle.

[0056] The first variable rigidity region 31 is provided, for example, on the inner side surface 21 of the left rear side frame 14, at a position closest to the rear bumper beam 16, near the rear end 14b of the left rear side frame 14. The first variable rigidity region 31 is formed to be curved and concave from the inner side surface 21 of the left rear side frame 14 toward the vehicle widthwise outward (i.e., the inner side of the left rear side frame 14), extending in the vehicle vertical direction. Therefore, the first variable rigidity region 31 is formed so that the rigidity of the left rear side frame 14 varies in the vehicle longitudinal direction.

[0057] The second variable rigidity region 32 is provided, for example, on the outer side surface 22 of the left rear side frame 14 at a position spaced apart toward the vehicle front relative to the first variable rigidity region 31. In other words, the second variable rigidity region 32 is provided at a different position in the longitudinal direction relative to the first variable rigidity region 31. The longitudinal direction is referred to as the longitudinal direction of the left rear side frame 14 (i.e., the vehicle front-rear direction).

[0058] The second variable rigidity region 32 is formed so as to curve and concave from the outer side surface 22 of the left rear side frame 14 toward the vehicle widthwise inner side (i.e., the inner side of the left rear side frame 14), extending in the vehicle vertical direction. Therefore, the second variable rigidity region 32 is formed so that the rigidity of the left rear side frame 14 varies in the vehicle longitudinal direction.

[0059] Thus, the first variable rigidity region 31 is provided on the inner side 21 of the left rear side frame 14. The second variable rigidity region 32 is provided on the outer side 22 of the left rear side frame 14. The first variable rigidity region 31 and the second variable rigidity region 32 are provided at intervals in the vehicle longitudinal direction.

[0060] Therefore, when an impact load is input to the left rear side frame 14 from the rear of the vehicle, the left rear side frame 14 bends outward in the vehicle width direction starting from the first rigidity change region 31. The left rear side frame 14 bends inward in the vehicle width direction starting from the second rigidity change region 32. In other words, the left rear side frame 14 deforms so as to bend outward and inward in the vehicle width direction starting from the first rigidity change region 31 and the second rigidity change region 32.

[0061] In this embodiment, the first variable rigidity region 31 is provided on the inner side surface 21 of the left rear side frame 14, and the second variable rigidity region 32 is provided on the outer side surface 22 of the left rear side frame 14. However, the present invention is not limited to this embodiment. As another example, the first variable rigidity region 31 may be provided on the outer side surface 22 of the left rear side frame 14, and the second variable rigidity region 32 may be provided on the inner side surface 21 of the left rear side frame 14.

[0062] In this embodiment, the first and second variable rigidity regions 31 and 32 are described as being curved and recessed toward the inside of the left rear frame 14. However, the present invention is not limited to this embodiment. Alternatively, the first and second variable rigidity regions may be formed so as to protrude toward the outside of the left rear frame 14. Alternatively, the first and second variable rigidity regions may be formed by forming an opening in the left rear frame 14 or by varying the wall thickness (plate thickness) of the left rear frame 14.

[0063] A plurality of fragile portions 41 to 46 are provided on the rear portion 14 c of the left rear side frame 14 .

[0064] In the present embodiment, six fragile portions 41 to 46 are exemplified: a first fragile portion 41 , a second fragile portion 42 , a third fragile portion 43 , a fourth fragile portion 44 , a fifth fragile portion 45 , and a sixth fragile portion 46 .

[0065] The plurality of fragile portions is not limited to six and can be arbitrarily selected.

[0066] The first fragile portion 41, the second fragile portion 42, and the third fragile portion 43 are provided at intervals along the vehicle front-rear direction on the upper surface 23 of the rear portion 14c of the left rear side frame 14. The first fragile portion 41, the second fragile portion 42, and the third fragile portion 43 are continuous in the vehicle width direction, for example, in a shape that protrudes upward from the upper surface 23 of the vehicle.

[0067] The first fragile portion 41 is provided at a position overlapping the first variable rigidity region 31 in the vehicle front-to-rear direction. For example, in the vehicle width direction, the first fragile portion 41 has an inner end 41a connected to the first variable rigidity region 31 and an outer end 41b connected to the outer side surface 22 of the left rear frame 14. The inner end 41a of the first fragile portion 41 can be spaced away from the first variable rigidity region 31, while the outer end 41b can be spaced away from the outer side surface 22 of the left rear frame 14.

[0068] The second fragile portion 42 is provided forward of the first fragile portion 41 in the vehicle, at a position overlapping the second variable rigidity region 32 in the vehicle longitudinal direction. For example, in the vehicle width direction, the inner end 42a of the second fragile portion 42 is connected to the inner side surface 21 of the left rear frame 14, and the outer end 42b is connected to the second variable rigidity region 32. The inner end 42a of the second fragile portion 42 can be spaced away from the inner side surface 21 of the left rear frame 14, while the outer end 42b can be spaced away from the second variable rigidity region 32.

[0069] The third fragile portion 43 is provided forward of the second fragile portion 42. The distance between the third fragile portion 43 and the second fragile portion 42 in the vehicle front-to-rear direction is, for example, the same as the distance between the first fragile portion 41 and the second fragile portion 42 in the vehicle front-to-rear direction. For example, in the vehicle width direction, the inner end 43a of the third fragile portion 43 is connected to the inner side surface 21 of the left rear frame 14, and the outer end 43b is connected to the outer side surface 22 of the left rear frame 14. The inner end 43a of the third fragile portion 43 can be spaced apart from the inner side surface 21 of the left rear frame 14, while the outer end 43b can be spaced apart from the outer side surface 22 of the left rear frame 14.

[0070] The fourth fragile portion 44, the fifth fragile portion 45, and the sixth fragile portion 46 are provided at intervals along the vehicle front-rear direction on the lower surface 24 of the rear portion 14c of the left rear side frame 14. The fourth fragile portion 44, the fifth fragile portion 45, and the sixth fragile portion 46 are continuous in the vehicle width direction, for example, in a shape that protrudes downward from the lower surface 24 of the vehicle.

[0071] The fourth fragile portion 44 is provided at a position overlapping the first rigidity varying region 31 in the vehicle longitudinal direction. The fourth fragile portion 44 is formed vertically symmetrically with respect to the first fragile portion 41. Therefore, detailed description of the fourth fragile portion 44 is omitted.

[0072] The fifth fragile portion 45 is provided at a position overlapping the second rigidity varying region 32 in the vehicle front of the fourth fragile portion 44. The fifth fragile portion 45 is formed symmetrically in the vertical direction with respect to the second fragile portion 42. Therefore, a detailed description of the fifth fragile portion 45 is omitted.

[0073] The sixth fragile portion 46 is provided in the vehicle forward direction of the fifth fragile portion 45. The distance between the sixth fragile portion 46 and the fifth fragile portion 45 in the vehicle front-rear direction is, for example, the same as the distance between the fourth fragile portion 44 and the fifth fragile portion 45 in the vehicle front-rear direction. The sixth fragile portion 46 is formed symmetrically with respect to the third fragile portion 43 in the vertical direction. Therefore, a detailed description of the sixth fragile portion 46 is omitted.

[0074] In this embodiment, the first to sixth fragile portions 41 to 46 are formed to protrude outward from the left rear frame 14, but the present invention is not limited thereto. As another example, the first to sixth fragile portions may be formed to be curved and recessed toward the inside of the left rear frame 14. Alternatively, the first to sixth fragile portions may be formed by forming an opening in the left rear frame 14 or by reducing the wall thickness (plate thickness) of the left rear frame 14.

[0075] like Figure 1 As shown, the right rear side frame 15 is formed bilaterally symmetrically with respect to the left rear side frame 14 in the vehicle width direction. Therefore, the multiple rigidity change regions and multiple fragile portions provided in the right rear side frame 15 are denoted by the same reference numerals as the first rigidity change region 31, the second rigidity change region 32, and the first to sixth fragile portions 41 to 46 of the left rear side frame 14, and detailed descriptions thereof are omitted.

[0076] Then, based on Figure 2 、 Figure 5 , an example will be described in which, when an impact load F1 is input to the rear floor structure 10 of the vehicle body structure Ve from the rear of the vehicle, the input impact load F1 is absorbed by the rear floor structure 10 .

[0077] Figure 5 This is a plan view illustrating the transmission of an impact load input from the rear of the vehicle to the rear floor structure of the vehicle body structure.

[0078] like Figure 2 、 Figure 5 As shown, a first rigidity change region 31 is provided on the inner side surface 21 of the left rear frame 14 , and a second rigidity change region 32 is provided on the outer side surface 22 of the left rear frame 14 .

[0079] A first rigidity change region 31 is provided on the inner side 26 of the right rear side frame 15, and a second rigidity change region 32 is provided on the outer side 27 of the right rear side frame 15. In this state, an impact load F1 is input to the rear floor structure 10 from the rear of the vehicle.

[0080] When an impact load F1 is input to the rear floor structure 10, the left rear side frame 14 can be deformed to bend outward and inward in the vehicle width direction, originating from the first and second rigidity varying regions 31 and 32. Similarly, the right rear side frame 15 can be deformed to bend outward and inward in the vehicle width direction, originating from the first and second rigidity varying regions 31 and 32. By deforming in this bending manner, the left and right rear side frames 14 and 15 absorb the input impact load F1.

[0081] Here, the upper panel 17 is connected to the upper surface 23 of the left rear side frame 14 and the upper surface 28 of the right rear side frame 15. The lower panel 18 is connected to the lower surface 24 of the left rear side frame 14 and the lower surface 29 of the right rear side frame 15. By deforming the left rear side frame 14 and the right rear side frame 15 so as to bend outward and inward in the vehicle width direction, load is transmitted from the left rear side frame 14 and the right rear side frame 15 to the upper panel 17 and the lower panel 18.

[0082] Specifically, a load F2 that stretches the upper panel 17 and the lower panel 18 outward in the vehicle width direction and a load F3 that compresses the upper panel 17 and the lower panel 18 inward in the vehicle width direction are transmitted from the left rear side frame 14 and the right rear side frame 15 to the upper panel 17 and the lower panel 18 .

[0083] Furthermore, a load F4 that deforms the upper panel 17 and the lower panel 18 toward the vehicle front is transmitted from the left rear side frame 14 and the right rear side frame 15 to the upper panel 17 and the lower panel 18 .

[0084] Thus, the load can be efficiently transmitted to the entire regions of the upper panel 17 and the lower panel 18 , and the entire regions of the upper panel 17 and the lower panel 18 can be appropriately deformed.

[0085] The first and second rigidity changing regions 31, 32 of the left and right rear side frames 14, 35 are provided at different locations in the vehicle longitudinal direction.

[0086] As a result, the left rear side frame 14 can be deformed to bend appropriately in the vehicle width direction starting from the first and second rigidity varying regions 31 and 32 without causing stress concentration on a portion of the left rear side frame 14. The right rear side frame 15 can be deformed to bend appropriately in the vehicle width direction starting from the first and second rigidity varying regions 31 and 32 without causing stress concentration on a portion of the right rear side frame 15.

[0087] As described above, the rear floor structure 10 allows the left and right rear side frames 14 and 15 to be deformed appropriately in the vehicle width direction. Furthermore, the rear floor structure 10 allows the entire upper and lower panels 17 and 18 to be deformed appropriately.

[0088] This can improve the load absorption efficiency of the left rear side frame 14, the right rear side frame 15, the upper panel 17, and the lower panel 18. This can contribute to the development of a sustainable transportation system.

[0089] Here, the left rear side frame 14 and the right rear side frame 15 are formed bilaterally symmetrically. Therefore, below, the left rear side frame 14 will be described, and detailed description of the right rear side frame 15 will be omitted.

[0090] In the left rear side frame 14, the first fragile portion 41, the second fragile portion 42, and the third fragile portion 43 are provided on the upper surface 23 so as to be continuous in the vehicle width direction. In the left rear side frame 14, the fourth fragile portion 44, the fifth fragile portion 45, and the sixth fragile portion 46 are provided on the lower surface 24 so as to be continuous in the vehicle width direction.

[0091] Therefore, the first to sixth fragile portions 41 to 46 can be deformed together with the first and second rigidity varying regions 31 and 32. This further appropriately promotes the deformation of the left rear side frame 14, which bends in the vehicle width direction starting from the first and second rigidity varying regions 31 and 32.

[0092] Buckling of the left rear side frame 14 due to stress concentration is suppressed, and the left rear side frame 14 can be appropriately bent in the vehicle width direction starting from the first and second rigidity change regions 31 and 32. Consequently, the load can be appropriately distributed (transmitted) across the entire area of ​​the upper panel 17 and lower panel 18. Consequently, the distributed load can appropriately deform the entire area of ​​the upper panel 17 and lower panel 18.

[0093] The rear portion 14c of the left rear side frame 14 is provided with a first rigidity change region 31 and a second rigidity change region 32. Therefore, when an impact load F1 is input from the rear of the vehicle, the rear portion 14c of the left rear side frame 14 can absorb the load by deforming so as to bend outward and inward in the vehicle width direction.

[0094] By bending the rear portion 14 c of the left rear side frame 14 outward and inward in the vehicle width direction, load is transmitted from the rear portion 14 c of the left rear side frame 14 to the rear end portions of the upper panel 17 and the lower panel 18 .

[0095] Specifically, a load F2 that stretches the rear ends of the upper and lower panels 17, 18 outward in the vehicle width direction, and a load F3 that compresses the rear ends of the upper and lower panels 17, 18 inward in the vehicle width direction are transmitted from the rear portion 14c of the left rear side frame 14 to the rear ends of the upper and lower panels 17, 18. A load F4 that deforms the rear ends of the upper and lower panels 17, 18 toward the vehicle front is transmitted from the rear portion 14c of the left rear side frame 14 to the upper and lower panels 17, 18. Thus, loads can be efficiently transmitted from the rear ends of the upper and lower panels 17, 18 to the entire area of ​​the upper and lower panels 17, 18.

[0096] Furthermore, the rear portion 14c of the left rear side frame 14 is provided with a first and second rigidity varying regions 31 and 32. Therefore, when an impact load F1 is input from the vehicle rear, the rear portion 14c can bend in the vehicle width direction before the upper and lower panels 17, 18 significantly deform toward the vehicle front. This allows the left rear side frame 14 to absorb the impact load F1 while efficiently transmitting the load to the entire upper and lower panels 17, 18.

[0097] As a result, the impact load F1 can be absorbed by the left rear side frame 14 and the load can be appropriately distributed over the entire areas of the wide upper and lower panels 17 and 18 , thereby improving the load absorption efficiency of the upper and lower panels 17 and 18 .

[0098] Furthermore, the first fragile portion 41 and the first variable rigidity region 31 are positioned so as to overlap in the vehicle front-to-rear direction. The second fragile portion 42 and the second variable rigidity region 32 are positioned so as to overlap in the vehicle front-to-rear direction. Therefore, the first fragile portion 41 and the second fragile portion 42 deform in response to the impact load F1 inputted from the vehicle rear to the left rear side frame 14, thereby accelerating deformation of the left rear side frame 14 toward the vehicle front.

[0099] The first fragile portion 41 is located at a position overlapping the first variable rigidity region 31 in the vehicle longitudinal direction. The second fragile portion 42 is located at a position overlapping the second variable rigidity region 32 in the vehicle longitudinal direction. This prevents stress from concentrating on the first variable rigidity region 31 and the second variable rigidity region 32, which are located at different positions in the longitudinal direction of the left rear side frame 14 (i.e., the vehicle longitudinal direction). By suppressing stress concentration on the first variable rigidity region 31 and the second variable rigidity region 32, buckling of the left rear side frame 14 in the vehicle longitudinal direction can be suppressed.

[0100] Therefore, the left rear side frame 14 can be reliably bent outward and inward in the vehicle width direction starting from the first and second rigidity change regions 31 and 32. As a result, the load F2 that pulls the upper and lower panels 17 and 18 outward in the vehicle width direction and the load F3 that compresses the upper and lower panels 17 and 18 inward in the vehicle width direction can be reliably transmitted from the left rear side frame 14 to the upper and lower panels 17 and 18.

[0101] [Modification]

[0102] In this embodiment, the present invention is applied to the rear floor structure 10 of the rear part of the vehicle. However, the present invention is not limited to this. As another modified example, the present invention can also be applied to the front floor structure of the front part of the vehicle. Figure 6 A front floor structure 100 according to a modified example will be described. In the modified example, components identical or similar to those of the rear floor structure 10 according to the embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0103] Figure 6 This is a plan view illustrating a front floor structure according to a modified example.

[0104] like Figure 6 As shown, a modified front floor structure 100 is provided at the front portion of a vehicle. Front floor structure 100 includes a left front side frame (side frame) 102 and a right front side frame (side frame) 104. A front bumper beam 106 is mounted across the front ends 102a, 104a, of the left and right front side frames 102, 104. An upper panel (panel) 107 is joined from above to the upper surfaces of the left and right front side frames 102, 104. Furthermore, a lower panel (panel) 108 is joined from below to the lower surfaces of the left and right front side frames 102, 104.

[0105] The left front frame 102 is located at the lower portion of the left side in the vehicle width direction at the front of the vehicle. The left front frame 102 extends in the vehicle front-to-rear direction from a rear end 102b to a front end 102a toward the front of the vehicle. The first and second rigidity varying regions 31, 32, and the first to sixth fragile portions 41, 46 are located in the front portion 102c of the left front frame 102.

[0106] The front portion 102 c is located further forward of the vehicle than the center of the left front side frame 102 in the vehicle front-rear direction and closer to the front end portion 102 a of the left front side frame 102 .

[0107] The term "close to the front end portion 102a" refers to a position that may not be completely in contact with the front end portion 102a. In the modified example, the front portion 102c is described as an example, ranging from the front end portion 102a to a position separated by a predetermined distance to the rear of the vehicle.

[0108] The right front side frame 104 is formed bilaterally symmetrically with respect to the left front side frame 102 in the vehicle width direction. Therefore, the multiple rigidity change regions and multiple fragile portions provided in the right front side frame 104 are denoted by the same reference numerals as the first rigidity change region 31, the second rigidity change region 32, and the first to sixth fragile portions 41 to 46 of the left front side frame 102, and detailed descriptions thereof will be omitted.

[0109] According to the front floor structure 100 of the modified example described above, the left front side frame 102 and the right front side frame 104 can be deformed so as to be bent appropriately in the vehicle width direction. In addition, according to the front floor structure 100, the entire area of ​​the upper panel 107 and the lower panel 108 can be deformed appropriately.

[0110] This can improve the load absorption efficiency of the left front side frame 102 , the right front side frame 104 , the upper panel 107 , and the lower panel 108 .

[0111] This can in turn contribute to the development of sustainable transport systems.

[0112] Here, the left front side frame 102 and the right front side frame 104 are formed bilaterally symmetrically. Therefore, below, the left front side frame 102 will be described, and detailed description of the right front side frame 104 will be omitted.

[0113] The front portion 102c of the left front side frame 102 is provided with a first rigidity change region 31 and a second rigidity change region 32. Therefore, when an impact load F5 is input from the front of the vehicle, the front portion 102c of the left front side frame 102 is deformed so as to bend outward and inward in the vehicle width direction, thereby absorbing the load.

[0114] By bending the front portion 102 c of the left front side frame 102 outward and inward in the vehicle width direction, a load is transmitted from the front portion 102 c of the left front side frame 102 to the front end portions of the upper panel 107 and the lower panel 108 .

[0115] Specifically, a load F6 that stretches the front ends of the upper and lower panels 107, 108 outward in the vehicle width direction, and a load F7 that compresses the front ends of the upper and lower panels 107, 108 inward in the vehicle width direction, are transmitted from the front portion 102c of the left front side frame 102 to the front ends of the upper and lower panels 107, 108. A load F8 that deforms the front ends of the upper and lower panels 107, 108 toward the vehicle rear is transmitted from the front portion 102c of the left front side frame 102 to the upper and lower panels 107, 108. Thus, loads can be efficiently transmitted from the front ends of the upper and lower panels 107, 108 to the entire area of ​​the upper and lower panels 107, 108.

[0116] Furthermore, the front portion 102c of the left front side frame 102 is provided with a first and a second rigidity variable region 31 and 32. Therefore, when an impact load F5 is input from the front of the vehicle, the front portion 102c can be bent in the vehicle width direction before the upper and lower panels 107 and 108 significantly deform toward the rear of the vehicle. This allows the left front side frame 102 to absorb the impact load F5 while efficiently transmitting the load to the entire area of ​​the upper and lower panels 107 and 108.

[0117] As a result, the left front side frame 102 can absorb the impact load F5 and appropriately distribute the load to the entire area of ​​the wide upper panel 107 and lower panel 108 , thereby improving the load absorption efficiency of the upper panel 107 and lower panel 108 .

[0118] According to the front floor structure 100 of the modified example, the same operations and effects as those of the rear floor structure 10 of the above-described embodiment can be obtained.

[0119] 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.

[0120] Furthermore, components in the above-described embodiments may be appropriately replaced with 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 structure, wherein: The vehicle body structure comprises: a panel disposed below the vehicle; and a side frame connected to the outer side of the panel in the vehicle width direction and extending in the front-rear direction of the vehicle, The side frame has a plurality of rigidity variation regions. The plurality of rigidity changing regions are arranged on the vehicle width direction outer side and the vehicle width direction inner side of the side frame, The rigidity changing region provided on the outer side in the vehicle width direction is provided at a position different in the longitudinal direction from the rigidity changing region provided on the inner side in the vehicle width direction.

2. The vehicle body structure according to claim 1, wherein: The side frame is provided with fragile portions that are continuous in the vehicle width direction on the vehicle upper side and the vehicle lower side.

3. The vehicle body structure according to claim 1, wherein: The side frame is arranged at the rear of the vehicle. The plurality of rigidity change regions are provided at positions close to rear end portions of the side frames.

4. The vehicle body structure according to claim 1, wherein: The side frame is arranged at the front of the vehicle. The plurality of rigidity change regions are provided at positions close to front end portions of the side frames.

5. The vehicle body structure according to claim 2, wherein: The fragile portion and the rigidity change region are provided at positions overlapping with each other in the front-rear direction of the vehicle.

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