Vehicle structure

Abstract

This vehicle structure comprises: a floor panel that has a mounting part having an in-vehicle device installed on the upper surface thereof; and a center member that is attached to the lower surface of the floor panel and connects two cross members arranged side-by-side in the vehicle front-rear direction. The center member extends linearly in the vehicle front-rear direction, has a fragile part on the lower part thereof toward the vehicle rear relative to the mounting part of the floor panel, and is more rigid toward the vehicle rear than toward the vehicle front with the fragile part as a boundary.

Description

Vehicle structure

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

[0002] Patent document 1 shows a vehicle structure having a rear floor panel on which a drive battery unit is arranged, rear side frames joined to both the left and right sides of the rear floor panel, a rear floor middle cross member extending in the vehicle width direction and joined to the rear side frames, a rear panel extending in the vehicle width direction along the rear end of the rear floor panel and joined to the rear end of the rear side frame, a box member joined to the center of the rear panel in the vehicle width direction, and a rear center member extending in the fore-and-aft direction and having its front end joined to the rear floor middle cross member and its rear end joined to the box member.

[0003] In this vehicle structure, the rear center member is composed of a front member that extends from the joint with the rear floor middle cross member to a position rearward of the fore-and-aft position corresponding to the location of the drive battery unit, an intermediate member whose front end is joined to the rear end of the front member and extends from the front member to the vicinity of the box member attached to the rear panel, and which is weaker than the front member and has a weak portion in the middle that is easily bent in the vertical direction, and a rear member whose front end is joined to the rear end of the intermediate member and extends from the intermediate member to the joint with the box member and is stronger than the intermediate member.

[0004] Japanese Patent Application Publication No. 2016-185739

[0005] In the vehicle structure of Patent Document 1, a rear center member is provided with bend lines at multiple locations in the vehicle's longitudinal direction, and weakened portions are provided at multiple locations in the vehicle's longitudinal direction, so that the rear center member is actively bent at multiple locations during a rear collision, thereby deforming the rear of the vehicle and absorbing the impact (rear collision energy).As a result, in a rear collision, the rear floor panel along with the rear side members are significantly deformed and compressed in the vehicle's longitudinal direction, which could cause rear vehicle structures such as the tailgate to come into contact with the battery unit located on the rear floor panel, damaging the battery unit.

[0006] Therefore, an object of the present invention is to provide a vehicle structure that can reduce damage to on-board equipment such as an installed battery even when an impact is applied from behind the vehicle, such as in a rear-end collision.

[0007] The present invention comprises the following configuration: A vehicle structure comprising: a floor panel having a mounting portion on an upper surface of which in-vehicle equipment is placed; and a center member attached to the underside of the floor panel and connecting two cross members that are aligned in the longitudinal direction of the vehicle, wherein the center member extends linearly in the longitudinal direction of the vehicle and has a weakened portion in a lower portion of the floor panel rearward of the mounting portion, and the rear side of the vehicle, with the weakened portion as a boundary, has higher rigidity than the front side of the vehicle.

[0008] According to the present invention, a vehicle structure can be provided that can reduce damage to on-board equipment even when an impact is applied from behind the vehicle, such as in a rear collision.

[0009] FIG. 1 is a bottom view of a floor panel for explaining the vehicle structure according to this embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a perspective view of the floor panel as viewed from the bottom side. FIG. 4 is a bottom view of the center member portion. FIG. 5 is a perspective view of the mounting portion on the top side of the floor panel. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view corresponding to line II-II in FIG. 1 of the rear of the vehicle deformed in the protection mode.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the symbol FR indicates the front of the vehicle, the symbol UP indicates the upper side of the vehicle, and the symbol HL indicates the width direction of the vehicle.

[0011] Fig. 1 is a bottom view of a floor panel 11 illustrating the vehicle structure according to this embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in Figs. 1 and 2, the vehicle structure according to this embodiment is primarily applied to the rear structural portion of a vehicle 100 such as an automobile.

[0012] The vehicle 100 includes a floor panel 11. The floor panel 11 is a plate material that constitutes the vehicle floor. The floor panel 11 is formed, for example, from a steel plate by press working or the like. A battery 13 is mounted on the upper surface of the floor panel 11 in the rear of the vehicle 100. The floor panel 11 has a mounting portion 15, and the battery 13 as an in-vehicle device is mounted on the mounting portion 15 of the floor panel 11. The battery 13 is a 12V battery that serves as a power source for driving and controlling various electrical components. Note that the battery 13 may be a drive battery in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or an electric vehicle (BEV). Furthermore, the in-vehicle device mounted on the mounting portion 13 is not limited to a battery, and any in-vehicle device such as an auxiliary device or an ECU may be mounted.

[0013] The vehicle 100 also includes a muffler 17 and a fuel tank 19. The muffler 17 and the fuel tank 19 are disposed below the floor panel 11. The muffler 17 is disposed in a position substantially below the mounting portion 15 on the floor panel 11, and the fuel tank 19 is disposed at a distance from the muffler 17 toward the front of the vehicle.

[0014] The vehicle 100 includes a chassis frame 21, and the floor panel 11 is provided on top of the chassis frame 21. The chassis frame 21 includes a pair of side members 23R, 23L. The side members 23R, 23L are spaced apart in the vehicle width direction and extend in the vehicle front-rear direction. The side member 23R is located on the right side in the vehicle width direction, and the side member 23L is located on the left side in the vehicle width direction. The chassis frame 21 also includes multiple cross members 25, 27. The cross members 25, 27 extend in the vehicle width direction at multiple locations spaced apart in the vehicle front-rear direction. Both ends of these cross members 25, 27 are joined to the side members 23R, 23L. The cross member 27 on the rear side of the vehicle is joined to the rear ends of the side members 23R, 23L.

[0015] The floor panel 11 has a center member 31. The center member 31 is attached to the underside of the floor panel 11. The center member 31 extends linearly in the front-to-rear direction of the vehicle. The front end of the center member 31 is joined to the cross member 25 on the front side of the vehicle, and the rear end is joined to the cross member 27 on the rear side of the vehicle. The center member 31 is joined to the cross members 25, 27 by, for example, welding.

[0016] The center member 31 is disposed in the center in the vehicle width direction and is disposed substantially parallel to the side members 23R, 23L. That is, the side members 23R, 23L are disposed side by side on both sides of the center member 31 in the vehicle width direction. A mounting portion 15 on the floor panel 11 on which the battery 13 is mounted is disposed at a position offset in the vehicle width direction relative to the center member 31. Specifically, the mounting portion 15 is disposed between the center member 31 on the floor panel 11 and the side member 23L on one side (left side) in the vehicle width direction. Note that the mounting portion 15 may also be disposed between the center member 31 on the floor panel 11 and the side member 23R on the other side (right side) in the vehicle width direction.

[0017] Fig. 3 is a perspective view of the floor panel 11 as viewed from the underside. Fig. 4 is a bottom view of the center member 31 portion.

[0018] 3 and 4, the center member 31 is made of steel and formed into a long, linear shape by bending. The center member 31 has a bottom plate 33, a pair of side plate parts 35, and a pair of flange parts 37. The side plate parts 35 extend upward from both side edges of the bottom plate part 33. The flange parts 37 extend away from the upper edges of the side plate parts 35. This gives the center member 31 a hat-shaped cross section and high rigidity.

[0019] The center member 31 has a flange portion 37 that is spot-welded to the floor panel 11. Joint points P at the flange portion 37 of the center member 31 to the floor panel 11 are spaced apart in the vehicle longitudinal direction.

[0020] The center member 31 has a weakened portion 41. The weakened portion 41 is provided near the rear end of the center member 31 in the vehicle front-rear direction. The weakened portion 41 is provided below the mounting portion 15 of the floor panel 11 on which the battery 13 is mounted and on the rear side of the vehicle.

[0021] The weakened portion 41 is a folded bead that protrudes upward along the vehicle width direction from the underside of the center member 31. Specifically, the weakened portion 41 is formed by protruding upward from the bottom plate portion 33 that constitutes the underside of the center member 31. As a result, the weakened portion 41 has a groove-shaped portion that extends along the vehicle width direction on the underside of the bottom plate portion 33 of the center member 31. By forming such a weakened portion 41, the strength of the underside portion of the center member 31 in the vehicle fore-and-aft direction is made lower at the weakened portion 41 than at other portions.

[0022] The center member 31 is divided into a front region 31A on the front side of the vehicle and a rear region 31B on the rear side of the vehicle, with the weakened portion 41 as the boundary. The rear region 31B of the center member 31 has a reinforcing bead 43. This reinforcing bead 43 is formed by recessing the central portion of the bottom plate portion 33 in the vehicle width direction along the front-to-rear direction of the vehicle. This makes the rear region 31B of the center member 31 more rigid than the front region 31A. Furthermore, the rear region 31B of the center member 31 has a wider width in the vehicle width direction than the front region 31A. This makes the rear region 31B of the center member 31 even more rigid than the front region 31A.

[0023] In this way, the center member 31 has a front region 31A at the front of the vehicle and a rear region 31B at the rear of the vehicle, with the weak portion 41 located toward the rear in the vehicle's fore-and-aft direction as the boundary, and the rear region 31B at the rear of the vehicle has higher rigidity than the front region 31A at the front of the vehicle.

[0024] The vehicle 100 has a connecting member 51 at the bottom of the floor panel 11. This connecting member 51 is connected to the rear end of the center member 31 and the cross member 27 at the rear of the vehicle and protrudes downward from the floor panel 11. The connecting member 51 is composed of a pair of left and right divided plate portions 53. These divided plate portions 53 are welded to the side plate portions 35 in the rear region 31B of the center member 31 and the cross member 27, and their lower ends are welded to each other. The connecting member 51 also has fastening holes 55 at its lower end. A fastening wire or rope is passed through the fastening holes 55 of the connecting member 51 to secure the vehicle 100 to a transport ship, transport vehicle, or the like when transporting the vehicle 100. The fastening holes 55 of the connecting member 51 also engage a towing wire or towing hook when towing another vehicle, or the like.

[0025] Fig. 5 is a perspective view of the mounting portion 15 on the upper surface side of the floor panel 11. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5.

[0026] As shown in Figures 5 and 6, the mounting portion 15 of the floor panel 11 has a battery tray 61. The mounting portion 15 of the floor panel 11 has a downwardly recessed portion 15a (see Figure 2), and the battery tray 61 is installed on the mounting portion 15 so as to fit into the recessed portion 15a. The battery tray 61 installed on the mounting portion 15 is located further forward in the vehicle than the weakened portion 41 of the center member 31. The battery tray 61 is formed by pressing a steel plate. The battery tray 61 has a recessed holding portion 63 and connection pieces 65, 67 provided on both sides of the holding portion 63 in the vehicle width direction. The battery 13 is fixed to the battery tray 61 by a fastener 14 (see Figure 2) while being fitted into the holding portion 63 of the battery tray 61.

[0027] When the battery tray 61 is installed so as to fit into the recessed portion 15a of the mounting portion 15 of the floor panel 11, one connecting piece 65 is connected to the center member 31, and the other connecting piece 67 is connected to the side member 23L located on the left side in the vehicle width direction. One connecting piece 65 is spot-welded by three-plate welding to the floor panel 11 and the flange portion 37 of the center member 31 in a state where it is overlapped. The other connecting piece 67 is spot-welded by three-plate welding to the floor panel 11 and the flange portion 23a of the side member 23L in a state where it is overlapped. Since the battery tray 61 is connected to the center member 31 and the side member 23L in this way, the rigidity of the mounting portion 15 of the floor panel 11 on which the battery 13 is mounted can be increased.

[0028] Next, a situation will be described in which an impact is applied from behind the vehicle 100 having the above vehicle structure. Figure 7 is a cross-sectional view corresponding to II-II in Figure 1 of the rear part of the vehicle deformed in the protection mode.

[0029] When an impact is applied to the vehicle 100 from behind, such as in a rear collision, the impact is transmitted to the chassis frame 21 .

[0030] Here, the rear of the vehicle 100 is equipped with a center member 31 attached to the underside of the floor panel 11, extending linearly in the fore-and-aft direction of the vehicle and joined to the cross members 25, 27. Therefore, the vehicle 100 can absorb an impact from behind without causing significant deformation of the floor panel 11. In other words, because the center member 31 extends linearly in the fore-and-aft direction of the vehicle 100, the center member 31 increases the rigidity of the floor panel 11, ensuring high impact resistance against impacts from behind the vehicle.

[0031] Furthermore, as shown in Figure 7, when a large impact is applied from the rear of the vehicle, in the vehicle 100, the center member 31 bends upward starting from the weak portion 41 at the bottom, and the floor panel 11 is deformed in a protective mode in which it is lifted by the center member 31.

[0032] In this protection mode, the area of ​​the floor panel 11 on the front side of the vehicle, which has the mounting portion 15 on which the battery 13 is mounted, is not compressed in the longitudinal direction of the vehicle, but is lifted upward and tilted toward the front of the vehicle while maintaining its shape. Therefore, the battery 13 mounted on the mounting portion 15 on the floor panel 11 further forward than the weak portion 41 of the vehicle is prevented from coming into contact with rear structures such as the tailgate of the vehicle 100, and the battery 13 is protected.

[0033] At this time, since the rigidity of the rear region 31B of the center member 31 is higher than that of the front region 31A, with the weak portion 41 as the boundary, deformation of the rear region 31B due to an impact from the rear of the vehicle is suppressed, and a protective mode in which the center member 31 is bent upward can be smoothly induced.

[0034] In addition, during deformation in this protection mode, the center member 31 bends upward, so the connecting member 51 provided at the rear end of the center member 31 displaces upward while limiting the amount of displacement toward the front of the vehicle. This prevents the connecting member 51 from coming into contact with the muffler 17 due to an impact from the rear of the vehicle. Furthermore, it also prevents the muffler 17 from being pushed toward the front of the vehicle and coming into contact with the fuel tank 19.

[0035] In this way, the vehicle structure according to this embodiment can reduce damage to the mounted battery 13 even when an impact is applied from behind the vehicle, such as in a rear-end collision. This reduces leakage of battery fluid or inability to drive electrical components due to damage to the battery 13, ensuring high safety.

[0036] Furthermore, since the weak portion 41 is a bendable bead that protrudes upward along the vehicle width direction from the underside of the center member 31, a large impact from the rear of the vehicle can smoothly bend the center member 31 at the bendable bead, thereby inducing the protection mode.

[0037] Furthermore, the center member 31 has a hat shape with a bottom plate portion 33, side plate portions 35, and flange portions 37, which increases its rigidity. Therefore, the center member 31 increases the rigidity of the floor panel 11, and when a large impact is applied to the center member 31 from the rear of the vehicle, deformation of the center member 31 in areas other than the weak portion 41 can be suppressed, allowing the protection mode to be smoothly induced.

[0038] Furthermore, the center member 31 has a reinforcing bead 43 recessed in the vehicle longitudinal direction in the rear region 31B on the vehicle rear side, with the weak portion 41 as the boundary, and the width in the vehicle width direction is wider in the rear region 31B on the vehicle rear side than in the front region 31A on the vehicle front side. Therefore, the rigidity of the center member 31 on the vehicle rear side, with the weak portion 41 as the boundary, is increased, and deformation on the vehicle rear side of the weak portion 41 due to an impact applied from the rear of the vehicle can be suppressed. This allows the center member 31 to bend smoothly at the weak portion 41, thereby inducing the protection mode.

[0039] In addition, the lower part of the floor panel 11 is provided with a connecting member 51 that is connected to the rear end of the center member 31 and the cross member 27 on the rear side of the vehicle, so that large impacts applied from the rear of the vehicle can be transmitted to the center member 31 via the connecting member 51, allowing the center member 31 to bend smoothly upward.

[0040] Furthermore, since the mounting portion 15 of the floor panel 11 is positioned at a position offset in the vehicle width direction relative to the center member 31, when a large impact is applied from the rear of the vehicle and the center member 31 is bent upward at the weak portion 41, the impact transmitted from the center member 31 to the battery 13 is reduced, thereby protecting the battery 13.

[0041] Furthermore, a battery tray 61 that holds the battery 13 is provided in the mounting portion 15 of the floor panel 11, and the battery tray 61 is positioned further forward of the vehicle than the fragile portion 41. This increases the rigidity of the mounting portion 15 of the floor panel 11 on which the battery 13 is mounted, and when a large impact applied from the rear of the vehicle causes the center member 31 to bend upward at the fragile portion 41, deformation of the mounting portion 15 is suppressed, thereby protecting the battery 13. Furthermore, by connecting the battery tray 61 to the center member 31 and the side member 23L, the rigidity of the mounting portion 15 of the floor panel 11 can be further increased by the battery tray 61.

[0042] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0043] As described above, this specification discloses the following: (1) A vehicle structure comprising: a floor panel having a mounting portion on an upper surface of which onboard equipment is placed; and a center member attached to the underside of the floor panel and connecting two cross members arranged in the vehicle longitudinal direction, wherein the center member extends linearly in the vehicle longitudinal direction and has a weakened portion in a lower portion of the floor panel rearward of the mounting portion, and the rearward side of the vehicle, with the weakened portion as a boundary, has higher rigidity than the frontward side of the vehicle. According to this vehicle structure, since the center member extends linearly in the vehicle longitudinal direction, the center member increases the rigidity of the floor panel, ensuring high impact resistance against impacts from the rear of the vehicle. Furthermore, when a large impact is applied from the rear of the vehicle, the center member bends upward starting from the weakened portion in the lower portion, and the floor panel is deformed in a protective mode in which it is lifted by the center member. This prevents onboard equipment mounted on the mounting portion forward of the weak portion of the floor panel from coming into contact with rear structures such as the vehicle tailgate, thereby protecting the onboard equipment. Furthermore, since the center member has higher rigidity on the rear side of the vehicle, with the weak part as the boundary, deformation of the center member rearward of the weak part due to an impact from the rear of the vehicle is suppressed, and a protection mode in which the center member is bent upward can be smoothly induced.

[0044] (2) The vehicle structure according to (1), wherein the weakened portion is a bendable bead that protrudes upward along the vehicle width direction from the underside of the center member. With this vehicle structure, a large impact from the rear of the vehicle can smoothly bend the center member at the bendable bead, thereby inducing the protection mode.

[0045] (3) The vehicle structure according to (1) or (2), wherein the center member has a bottom plate portion, side plate portions extending upward from both edges of the bottom plate portion, and flange portions extending away from the upper edges of the side plate portions, the flange portions being joined to the floor panel. This vehicle structure allows the center member to be hat-shaped to increase its rigidity. Therefore, the center member can increase the rigidity of the floor panel, and when a large impact is applied to the center member from the rear of the vehicle, deformation of the center member can be suppressed in areas other than the weak portion, smoothly inducing the protection mode.

[0046] (4) The vehicle structure according to any one of (1) to (3), wherein the center member has a reinforcing bead recessed along the vehicle longitudinal direction on the vehicle rear side, with the weak portion as a boundary. This vehicle structure increases the rigidity of the center member on the vehicle rear side, with the weak portion as a boundary, and can suppress deformation on the vehicle rear side of the weak portion due to an impact applied from the rear of the vehicle. This allows the center member to bend smoothly at the weak portion, thereby inducing the protection mode.

[0047] (5) The vehicle structure according to any one of (1) to (4), wherein the width of the center member in the vehicle width direction is wider on the vehicle rear side than on the vehicle front side, with the weak portion as a boundary. According to this vehicle structure, the width of the center member in the vehicle width direction is wider on the vehicle rear side, with the weak portion as a boundary, and rigidity can be easily increased.

[0048] (6) The vehicle structure according to any one of (1) to (5), further comprising a connecting member at a lower portion of the floor panel, the connecting member being connected to the rear end of the center member and the cross member at the rear of the vehicle. With this vehicle structure, a large impact applied from the rear of the vehicle can be transmitted to the center member via the connecting member, allowing the center member to bend smoothly upward.

[0049] (7) The vehicle structure according to any one of (1) to (6), wherein the mounting portion is disposed at a position offset in the vehicle width direction relative to the center member. With this vehicle structure, when a large impact applied from the rear of the vehicle causes the center member to bend upward at the weak portion, the impact transmitted from the center member to the on-board equipment can be reduced, thereby protecting the on-board equipment.

[0050] (8) The vehicle structure according to any one of (1) to (7), wherein the mounting portion of the floor panel has a tray for holding the on-board equipment, and the tray is disposed forward of the fragile portion. This vehicle structure can increase the rigidity of the mounting portion of the floor panel on which the on-board equipment is mounted. This can reduce deformation of the mounting portion and protect the on-board equipment when a large impact applied from the rear of the vehicle causes the center member to bend upward at the fragile portion.

[0051] (9) The vehicle structure according to (8), wherein the tray is connected to the center member and one of a pair of side members arranged on both sides of the center member in the vehicle width direction. According to this vehicle structure, the tray can further increase the rigidity of a mounting portion of a floor panel on which on-board equipment is mounted.

[0052] (10) The vehicle structure according to any one of (1) to (9), wherein the on-board device is a battery. With this vehicle structure, the battery can be protected.

[0053] REFERENCE SIGNS LIST 11 Floor panel 13 Battery (vehicle equipment) 15 Mounting portion 25, 27 Cross member 31 Center member 33 Bottom plate portion 35 Side plate portion 37 Flange portion 41 Weak portion 43 Reinforcing bead 51 Connection member 61 Battery tray (tray)

Claims

1. A vehicle structure comprising: a floor panel having a mounting portion on the upper surface on which in-vehicle equipment is placed; and a center member attached to the underside of the floor panel and connecting two cross members that are aligned in the fore-and-aft direction of the vehicle, wherein the center member extends linearly in the fore-and-aft direction of the vehicle and has a weak portion at its lower part on the rear side of the floor panel relative to the mounting portion, and the rear side of the vehicle, with the weak portion as the boundary, has higher rigidity than the front side of the vehicle.

2. A vehicle structure according to claim 1, wherein the weakened portion is a bent bead that protrudes upward along the vehicle width direction from the lower surface of the center member.

3. A vehicle structure as set forth in claim 1 or 2, wherein the center member has a bottom plate portion, side plate portions extending upward from both edges of the bottom plate portion, and flange portions extending away from each other from the upper edges of the side plate portions, and the flange portions are joined to the floor panel.

4. A vehicle structure according to any one of claims 1 to 3, wherein the center member has a reinforcing bead recessed along the longitudinal direction of the vehicle on the rear side of the vehicle, with the weakened portion as a boundary.

5. A vehicle structure according to any one of claims 1 to 4, wherein the width of the center member in the vehicle width direction is wider at the rear side of the vehicle than at the front side of the vehicle, with the weakened portion as the boundary.

6. A vehicle structure according to any one of claims 1 to 5, wherein a connecting member is provided at the lower part of the floor panel, the connecting member being connected to the rear end of the center member and the cross member at the rear of the vehicle.

7. A vehicle structure according to any one of claims 1 to 6, wherein the mounting portion is disposed at a position offset in the vehicle width direction relative to the center member.

8. A vehicle structure according to any one of claims 1 to 7, wherein the mounting portion of the floor panel has a tray that holds the on-board equipment, and the tray is positioned further forward in the vehicle than the weak portion.

9. A vehicle structure according to claim 8, wherein the tray is connected to the center member and one of a pair of side members arranged on both sides of the center member in the vehicle width direction.

10. The vehicle structure according to any one of claims 1 to 9, wherein the on-board device is a battery.

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