WO2025197049A1 - Vehicle structure - Google Patents

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

The present invention relates to a vehicle structure.

Patent Document 1 shows a vehicle structure having a rear floor panel on which a drive battery unit is located, 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 ends of the rear side frames, 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.

In this vehicle structure, the rear center member is composed of a front member that extends from its joint with the rear floor middle cross member to a position rearward of the longitudinal 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 part 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 which is stronger than the intermediate member.

Japanese Patent Application Publication No. 2016-185739

In the vehicle structure of Patent Document 1, the rear center member has bend lines pre-installed at multiple locations in the vehicle's longitudinal direction, and weak portions are provided at multiple locations in the vehicle's longitudinal direction. During a rear-end collision, the rear center member is actively bent at multiple locations, deforming the rear of the vehicle and absorbing the impact (rear-end collision energy). As a result, in a rear-end 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, potentially damaging the battery unit.

The present invention therefore aims to provide a vehicle structure that can minimize damage to onboard equipment such as the battery, even when an impact is applied from behind the vehicle, such as in a rear-end collision.

The present invention comprises the following configurations.
a floor panel having a mounting portion on an upper surface of which an in-vehicle device is placed;
a center member attached to the underside of the floor panel and connecting two cross members arranged in the front-rear direction of the vehicle;
Equipped with
The center member is
It extends linearly in the front-to-rear direction of the vehicle,
a weakened portion is provided at a lower portion of the floor panel on a vehicle rear side of the mounting portion,
The rear side of the vehicle has higher rigidity than the front side of the vehicle, with the weakened portion as a boundary.
Vehicle structure.

The present invention provides a vehicle structure that can minimize damage to onboard equipment even when an impact is applied from behind the vehicle, such as in a rear-end collision.

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. FIG. 3 is a perspective view of the floor panel as viewed from the underside. FIG. 4 is a bottom view of the center member portion. FIG. 5 is a perspective view of the mounting portion on the upper surface side of the floor panel. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a cross-sectional view corresponding to II-II in FIG. 1 of the rear part of the vehicle deformed in the protection mode.

Embodiments of the present invention will be described in detail below with reference to the drawings. In the following drawings, the symbol FR indicates the front of the vehicle, the symbol UP indicates the top of the vehicle, and the symbol HL indicates the vehicle width direction.

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.

The vehicle 100 is equipped with a floor panel 11. This floor panel 11 is a plate material that constitutes the floor of the vehicle. The floor panel 11 is formed from a steel plate, for example, by pressing. A battery 13 is placed on the upper surface of the floor panel 11 at the rear of the vehicle 100. The floor panel 11 has a mounting portion 15, and the battery 13, which serves as an on-board 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. The battery 13 may also be a drive battery in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or an electric vehicle (BEV). Furthermore, the on-board equipment mounted on the mounting section 13 is not limited to a battery; any on-board equipment such as auxiliary machinery, ECU, etc. may be mounted.

The vehicle 100 also includes a muffler 17 and a fuel tank 19. The muffler 17 and fuel tank 19 are located below the floor panel 11. The muffler 17 is located approximately below the mounting portion 15 on the floor panel 11, and the fuel tank 19 is located further forward in the vehicle than the muffler 17 and at a distance.

The vehicle 100 has a chassis frame 21, and the floor panel 11 is provided on top of the chassis frame 21. The chassis frame 21 has a pair of side members 23R, 23L. The side members 23R, 23L are spaced apart in the vehicle width direction and extend in the front-to-rear direction of the vehicle. 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 has 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-to-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.

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 longitudinal 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, for example, by welding.

The center member 31 is positioned in the center in the vehicle width direction and is arranged approximately parallel to the side members 23R, 23L. In other words, the side members 23R, 23L are arranged side by side on both sides of the center member 31 in the vehicle width direction. The mounting portion 15 on the floor panel 11 on which the battery 13 is mounted is arranged at a position offset in the vehicle width direction from the center member 31. Specifically, the mounting portion 15 is arranged 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 arranged 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.

Figure 3 is a perspective view of the floor panel 11 from the underside. Figure 4 is a bottom view of the center member 31.

As shown in Figures 3 and 4, the center member 31 is made of steel and is formed into a long, linear shape by bending. This center member 31 has a bottom plate portion 33, a pair of side plate portions 35, and a pair of flange portions 37. The side plate portions 35 extend upward from both side edges of the bottom plate portion 33. The flange portions 37 extend away from the upper edges of each side plate portion 35. This gives the center member 31 a hat-shaped cross section and high rigidity.

The center member 31 is joined to the floor panel 11 by spot welding at its flange portion 37. The joining points P at which the center member 31's flange portion 37 is joined to the floor panel 11 are spaced apart in the fore-and-aft direction of the vehicle.

The center member 31 has a weak portion 41. The weak portion 41 is located near the rear end of the center member 31 in the vehicle's fore-and-aft direction. This weak portion 41 is located below the mounting portion 15 of the floor panel 11, on which the battery 13 is mounted, and toward the rear of the vehicle.

The weak portion 41 is a folded bead that protrudes upward along the vehicle width direction from the underside of the center member 31. Specifically, the weak 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 weak portion 41 has a groove-shaped portion that runs along the vehicle width direction on the underside of the bottom plate portion 33 of the center member 31. By forming such a weak portion 41, the strength of the underside portion of the center member 31 in the vehicle fore-and-aft direction is lower at the weak portion 41 than at other portions.

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 weak 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. The rear region 31B of the center member 31 is also wider 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.

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 rearward in the vehicle longitudinal 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.

The vehicle 100 has a connecting member 51 located below 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 sections 53. These divided plate sections 53 are welded to the side plate sections 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 a fastening hole 55 at its lower end. A securing wire or rope is passed through the fastening hole 55 of the connecting member 51 to secure the vehicle 100 to a transport ship, transport vehicle, etc. when transporting the vehicle 100. A towing wire or towing hook is also engaged through the fastening hole 55 of the connecting member 51 when towing another vehicle, etc.

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

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 this mounting portion 15 is located further forward of the vehicle than the weak 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 fixing device 14 (see Figure 2) while being fitted into the holding portion 63 of the battery tray 61.

When the battery tray 61 is installed so that it fits into the recessed portion 15a of the mounting portion 15 of the floor panel 11, one connection piece 65 is connected to the center member 31, and the other connection piece 67 is connected to the side member 23L located on the left side in the vehicle width direction. One connection piece 65 is spot welded by triple welding while overlapping the floor panel 11 and the flange portion 37 of the center member 31. The other connection piece 67 is spot welded by triple welding while overlapping the floor panel 11 and the flange portion 23a of the side member 23L. In this way, connecting the battery tray 61 to the center member 31 and the side member 23L increases the rigidity of the mounting portion 15 of the floor panel 11 on which the battery 13 is mounted.

Next, we will explain what happens when an impact is applied from behind the vehicle 100 equipped with the above vehicle structure. Figure 7 is a cross-sectional view corresponding to II-II in Figure 1 of the rear of the vehicle deformed in the protection mode.

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

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 is able to absorb an impact from behind without the floor panel 11 undergoing significant deformation. In other words, because the center member 31 in the vehicle 100 extends linearly in the fore-and-aft direction of the vehicle, this center member 31 increases the rigidity of the floor panel 11, ensuring high impact resistance against impacts from behind the vehicle.

Furthermore, as shown in Figure 7, when a large impact is applied from the rear of the vehicle, the center member 31 of the vehicle 100 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 up by the center member 31.

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

In this case, the rear region 31B of the center member 31 is made more rigid than the front region 31A, with the weak portion 41 as the boundary. This prevents deformation of the rear region 31B due to an impact from the rear of the vehicle, and smoothly induces a protection mode in which the center member 31 bends upward.

In addition, during deformation in this protection mode, the center member 31 bends upward, so the connecting member 51 attached to 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.

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

Furthermore, the weakened portion 41 is a bendable bead that protrudes upward along the vehicle width direction from the underside of the center member 31, so that a large impact from the rear of the vehicle can smoothly bend the center member 31 at the bendable bead, inducing the protective mode.

Furthermore, the center member 31 is hat-shaped and has a bottom panel portion 33, side panel portions 35, and flange portions 37, which increases its rigidity. Therefore, the center member 31 not only increases the rigidity of the floor panel 11, but also suppresses deformation of the center member 31 in areas other than the weak portion 41 when a large impact is applied to the center member 31 from the rear of the vehicle, allowing the protection mode to be smoothly induced.

Furthermore, the center member 31 has a reinforcing bead 43 recessed in the longitudinal direction of the vehicle in the rear region 31B on the rear side of the vehicle, 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 rear side of the vehicle than in the front region 31A on the front side of the vehicle. Therefore, the rigidity of the center member 31 on the rear side of the vehicle is increased with the weak portion 41 as the boundary, and deformation on the rear side of the vehicle beyond 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, inducing the protection mode.

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

Furthermore, 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. Therefore, when a large impact from the rear of the vehicle causes the center member 31 to bend 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.

In addition, a battery tray 61 that holds the battery 13 is provided in the mounting portion 15 of the floor panel 11, and is positioned further forward of the vehicle than the weak 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 from the rear of the vehicle causes the center member 31 to bend upward at the weak portion 41, deformation of the mounting portion 15 is suppressed, 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 this battery tray 61.

As such, the present invention is not limited to the above-described embodiments, and the 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 disclosures in the specification and well-known technology, and these modifications and applications are within the scope of the protection sought.

As described above, the present specification discloses the following:
(1) a floor panel having a mounting portion on an upper surface of which an in-vehicle device is placed;
a center member attached to the underside of the floor panel and connecting two cross members arranged in the front-rear direction of the vehicle;
Equipped with
The center member is
It extends linearly in the front-to-rear direction of the vehicle,
a weakened portion is provided at a lower portion of the floor panel on a vehicle rear side of the mounting portion,
A vehicle structure, wherein a rear side of the vehicle, with the weak portion as a boundary, has higher rigidity than a front side of the vehicle.
According to this vehicle structure, the center member extends linearly in the longitudinal direction of the vehicle, and therefore the center member increases the rigidity of the floor panel, ensuring high impact resistance against impacts from behind the vehicle.
Furthermore, in the event of a large impact from the rear of the vehicle, the center member bends upward starting from the weak portion at its lower part, and the floor panel is deformed in a protective mode in which it is lifted by the center member. This prevents on-board equipment mounted in a mounting portion on the floor panel further forward than the weak portion from coming into contact with rear structures such as the vehicle tailgate, thereby protecting the on-board equipment. Moreover, because the center member has higher rigidity on the rear side of the vehicle, with the weak portion as a boundary, deformation of the center member on the rear side of the weak portion due to an impact from the rear of the vehicle is suppressed, and the protective mode in which the center member bends upward can be smoothly induced.

(2) The vehicle structure according to (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.
According to this vehicle structure, a large impact from the rear of the vehicle can cause the center member to bend smoothly at the breaking bead, thereby inducing the protection mode.

(3) A vehicle structure according to (1) or (2), wherein the center member has a bottom panel portion, side panel portions extending upward from both edges of the bottom panel portion, and flange portions extending away from each other from the upper edges of the side panel portions, and the flange portions are joined to the floor panel.
This vehicle structure allows the hat-shaped center member to increase its rigidity, thereby increasing the rigidity of the floor panel and suppressing deformation of the center member in areas other than the weak points when a large impact is applied to the center member from the rear of the vehicle, allowing the protection mode to be smoothly triggered.

(4) The vehicle structure according to any one of (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.
This vehicle structure increases the rigidity of the center member on the vehicle rear side, with the weak portion as the 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, inducing the protection mode.

(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 weakened portion as a boundary.
According to this vehicle structure, the width of the center member in the vehicle width direction can be increased on the vehicle rear side, with the weak portion as a boundary, thereby easily increasing rigidity.

(6) A vehicle structure according to any one of (1) to (5), further comprising a connecting member at the 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.
According to 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.

(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.
According to this vehicle structure, when a large impact is applied from the rear of the vehicle and the center member is bent 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.

(8) The mounting portion of the floor panel has a tray that holds the in-vehicle device,
The vehicle structure according to any one of (1) to (7), wherein the tray is disposed on the vehicle front side relative to the weak portion.
This vehicle structure increases the rigidity of the mounting portion of the floor panel on which the on-board equipment is mounted, thereby minimizing deformation of the mounting portion and protecting the on-board equipment when a large impact from the rear of the vehicle causes the center member to bend upward at the weak portion.

(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 the mounting portion of the floor panel on which the in-vehicle equipment is mounted.

(10) The in-vehicle device is a battery.
A vehicle structure according to any one of (1) to (9).
This vehicle structure can protect the battery.

11 Floor panel 13 Battery (in-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 (10)

a floor panel having a mounting portion on an upper surface of which an in-vehicle device is placed;
a center member attached to the underside of the floor panel and connecting two cross members arranged in the front-rear direction of the vehicle;
Equipped with
The center member is
It extends linearly in the front-to-rear direction of the vehicle,
a weakened portion is provided at a lower portion of the floor panel on a vehicle rear side of the mounting portion,
The rear side of the vehicle has higher rigidity than the front side of the vehicle, with the weakened portion as a boundary.
Vehicle structure. The weakened portion is a bent bead that protrudes upward along the vehicle width direction from the lower surface of the center member.
The vehicle structure according to claim 1 . The center member has a bottom plate portion, side plate portions extending upward from both edge portions of the bottom plate portion, and flange portions extending in directions away from each other from upper edges of the side plate portions, and the flange portions are joined to the floor panel.
3. A vehicle structure according to claim 1 or 2. The center member has a reinforcing bead recessed along the vehicle longitudinal direction on the vehicle rear side with the weakened portion as a boundary.
The vehicle structure according to any one of claims 1 to 3. The center member has a width in the vehicle width direction that is wider on a vehicle rear side than on a vehicle front side, with the weakened portion as a boundary.
The vehicle structure according to any one of claims 1 to 4. a connecting member provided 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;
The vehicle structure according to any one of claims 1 to 5. The mounting portion is disposed at a position offset in the vehicle width direction with respect to the center member.
The vehicle structure according to any one of claims 1 to 6. the mounting portion of the floor panel has a tray for holding the in-vehicle device,
The tray is disposed on the vehicle front side relative to the fragile portion.
The vehicle structure according to any one of claims 1 to 7. 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.
The vehicle structure according to claim 8. the in-vehicle device is a battery,
The vehicle structure according to any one of claims 1 to 9.