Vehicle rear structure

Abstract

The present invention provides a vehicle rear structure capable of suppressing peak loads of rear-end collision loads and efficiently absorbing rear-end collision loads. The vehicle rear structure includes: a central frame disposed at a position relative to the center of the vehicle width direction and extending rearward along the vehicle's longitudinal direction, on both sides of the central frame; and a bumper beam disposed rearward of the central frame and overlapping it when viewed from the longitudinal direction, the bumper beam being capable of being crushed by rear-end collision loads.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-110186, filed on July 1, 2021, the contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the rear structure of a vehicle. Background Technology

[0003] As a rear structure of motor vehicles, there are technologies disclosed that include a bumper beam extending along the rear bumper in the vehicle width direction and load-absorbing portions extending forward from both sides of the bumper beam in the vehicle width direction (for example, see Japanese Patent Application Publication No. 2020-199842). The front end of the load-absorbing portion is provided and joined to the rear end of a side frame that extends along the front-rear direction and is attached to both sides of the rear floor in the vehicle width direction.

[0004] Under this configuration, when a load is applied to the rear of the vehicle from behind (rear-end collision load), the bumper beam first bends and deforms to bear the rear-end collision load. Then, any remaining rear-end collision load from the bumper beam is transferred to the load-absorbing section, which then bears the load. Summary of the Invention

[0005] In the aforementioned prior art, the rear-impact load that can be absorbed by the bumper beam is limited to a very small load. Most of the rear-impact load cannot be completely absorbed by the bending deformation of the bumper beam and is instead borne by the load-absorbing section. Therefore, the following problem exists: during the period before the rear-impact load is applied to the load-absorbing section, the rear-impact load is borne by the bending deformation of the bumper beam, thus taking a long time to reach the peak load of the rear-impact load, and the peak load is prone to becoming larger.

[0006] In addition, there is a problem that the rear collision load applied to the bumper beam is difficult to transfer to the load absorption part and cannot efficiently absorb the rear collision load.

[0007] Furthermore, the load-absorbing sections are located on both sides of the vehicle in the width direction. Therefore, when the rear-end collision load is applied at a position offset from the center of the rear of the vehicle in the width direction, the rear-end collision load applied to each load-absorbing section becomes uneven. As a result, there is a possibility that the load-absorbing sections may not absorb the rear-end collision load completely, and the side frames may suffer damage exceeding the necessary level.

[0008] The present invention provides a vehicle rear structure capable of suppressing the peak load of rear-end collision loads and efficiently absorbing rear-end collision loads.

[0009] (1) A vehicle rear structure of one aspect of the present invention (e.g., vehicle rear structure 1 of the embodiment) is characterized by comprising: a central frame (e.g., central frame 15 of the embodiment), which is disposed on the side of the vehicle (e.g., vehicle 100 of the embodiment) in the width direction and at the rear, and extends along the front-rear direction of the vehicle; and a bumper beam (e.g., bumper beam 21 of the embodiment), which is arranged behind the central frame and is disposed at a position that overlaps with the central frame when viewed from the front-rear direction, the bumper beam being capable of being crushed by a rear collision load.

[0010] By constructing it as described in (1) above, the bumper beam can withstand the rear-end collision load while being crushed. Furthermore, the rear-end collision load is transferred to the central frame as the bumper beam is crushed. Since the central frame extends along the longitudinal direction, its mechanical strength is easily ensured. As a result, the central frame can reliably withstand the rear-end collision load. Therefore, from the moment the rear-end collision load is applied, the bumper beam can reliably crush and absorb the rear-end collision load, while the central frame simultaneously bears the load. Additionally, even if the input position of the rear-end collision load is slightly offset from the center of the vehicle width direction, the rear-end collision load is first transferred to the central frame. Therefore, the peak load of the rear-end collision load can be suppressed, and the rear-end collision load can be absorbed efficiently.

[0011] (2) Based on the above (1) scheme, it is also possible to have a rear plate member (e.g., the rear plate member 20 in the embodiment) disposed between the central frame and the bumper beam, and the bumper beam is connected to the central frame via the rear plate member.

[0012] By constructing the structure as described in (2) above, the rear impact load applied to the bumper beam can also be transferred to the rear panel members. This disperses the rear impact load applied to the bumper beam to the rear panel members, in addition to the central frame. Therefore, the rear impact load is not concentrated on specific vehicle components other than the bumper beam. As a result, damage to the vehicle from rear impact loads can be reliably suppressed.

[0013] (3) Based on the above (2) configuration, it may also include: a crossbeam (e.g., the crossbeam 18 in the embodiment), which is disposed in front of the central frame and extends along the vehicle width direction; and a side frame (e.g., the rear side frame 2 in the embodiment), which is disposed on both sides in the vehicle width direction, the front part of the central frame (e.g., the front end 15b in the embodiment) is connected to the crossbeam, and the two ends of the crossbeam in the vehicle width direction are respectively connected to the rear part of the side frame (e.g., the rear end 2a in the embodiment).

[0014] By constructing the structure as described in (3) above, rear-impact loads can be transferred to the crossbeams via the central frame, and further transferred to the side frames located on both sides in the vehicle width direction. The rear-impact loads can be evenly distributed to both side frames via the central frame. Therefore, damage to the vehicle from rear-impact loads can be suppressed more reliably.

[0015] (4) Based on the above (3) scheme, the crossbeam may also extend in an inclined manner as it gradually moves forward from the central frame toward the two outer sides in the vehicle width direction.

[0016] By constructing it as described in (4) above, it is possible to easily transfer the rear impact load applied to the central frame to the side frames compared to the case where the crossbeam extends in a straight line in the vehicle width direction.

[0017] (5) Based on the above (4) scheme, the central frame may also extend in a straight line in the front-back direction.

[0018] By constructing it as described in (5) above, the rearward collision load applied to the central frame can be reliably transferred to the crossbeams compared to the case where the central frame is bent. Therefore, the rearward collision load can be reliably distributed to the entire rear of the vehicle.

[0019] (6) Based on the above (2) scheme, the central frame, the bumper beam and the rear plate component can also be fixed in the same position.

[0020] By constructing it as described in (6) above, the rear impact load applied to the bumper beam can be transferred to the central frame more efficiently and effectively.

[0021] (7) Based on the above (1) configuration, it is also possible to have a rear floor (e.g., rear floor 5 in the embodiment) disposed at the rear of the vehicle, the rear floor being composed of a double-plate member structure (e.g., double-plate member structure 10 in the embodiment) having an upper plate member (e.g., upper plate member 11 in the embodiment) and a lower plate member (e.g., lower plate member 12 in the embodiment) disposed below the upper plate member, and the central frame being provided on the lower surface of the upper plate member (e.g., lower surface 11d in the embodiment).

[0022] By constructing it as described in (7) above, the load applied to the bumper beam can also be transferred to the rear floor. The rear floor is constructed of a double-plate structure, thus further dispersing the rear collision load on the rear plate members. Therefore, it is possible to more reliably suppress the damage to the vehicle caused by the rear collision load.

[0023] (8) Based on the configuration of the above (7), the bumper beam may be formed by bending in a way that bulges rearward in the section from the upper plate member to the lower plate member, and the upper fixing part of the bumper beam (e.g., the upper fixing part 21d in the embodiment) is offset in the vertical direction relative to the rear end of the upper plate member (e.g., the flange part 19a in the embodiment), and the lower fixing part of the bumper beam (e.g., the lower fixing part 21e in the embodiment) is offset in the vertical direction relative to the rear end of the lower plate member (e.g., the flange part 19b in the embodiment).

[0024] By constructing it as described in (8) above, the rear-impact load can be preferentially transferred to the central frame over the upper and lower plate members. That is, the positions of the fixing parts of the bumper beam are offset relative to the rear ends of the upper and lower plate members, so the rear-impact load applied to the bumper beam is not efficiently transferred to the individual plate members. In contrast, the rear-impact load is efficiently transferred to the central frame. As a result, the function of the central frame can be fully utilized.

[0025] Furthermore, when integrating the central frame, bumper beam, rear panel components, and floor into a single unit, such as using spot welding, it is possible to avoid completely overlapping the central frame, bumper beam, rear panel components, and floor during spot welding. Therefore, it is possible to suppress the reduction in strength caused by spot welding.

[0026] According to the solution of the present invention, the peak load of the rear-end collision load at the rear of the vehicle can be suppressed, and the rear-end collision load can be absorbed efficiently. Attached Figure Description

[0027] Figure 1 This is a perspective view of the lower side of the rear structure of the vehicle in the embodiment of the present invention, viewed from the left rear.

[0028] Figure 2 This is a diagram showing a cross-section of the rear structure of a vehicle in an embodiment of the present invention, near the center in the vehicle width direction, along the front-rear and vertical directions.

[0029] Figure 3 yes Figure 1 III-direction view.

[0030] Figure 4 This is a partially exploded perspective view of the lower side of the rear structure of the vehicle in the embodiment of the present invention, viewed from a rearward angle.

[0031] Figure 5 This is a line graph showing the variation of the rear collision load on the rear structure of the vehicle in an embodiment of the present invention.

[0032] Figure 6This is a plan view of the rear structure of a vehicle, showing a modified example of the crossbeam in an embodiment of the present invention, viewed from below. Detailed Implementation

[0033] Next, embodiments of the present invention will be described based on the accompanying drawings. In the following description, the direction in front of the vehicle 100 in the direction of travel will be referred to as "front," the direction behind the vehicle 100 will be referred to as "rear," the vertical direction will be referred to as "up" or "down," and the width direction of the vehicle 100 will be referred to as "width direction" or "left-right direction." In the following description, arrows will be marked at appropriate locations in each drawing: arrow FR indicating the front of the vehicle 100, arrow UP indicating the top of the vehicle 100, and arrow LH indicating the left side of the vehicle. Furthermore, in the following description, "joining" refers to joining performed by welding, such as spot welding.

[0034] Rear Structure of Vehicles

[0035] Figure 1 This is a perspective view of the lower side of the rear structure 1 (hereinafter referred to as the vehicle rear structure 1) of the vehicle 100, viewed from the left rear. Figure 1 To make the explanation easier to understand, some parts (especially the lower plate component 12) have been omitted from the illustration. Figure 2 It is a diagram showing a cross-section of the rear structure 1 of the vehicle in the width direction near the center, along the front-rear and vertical directions.

[0036] like Figure 1 , Figure 2 As shown, in the rear structure 1 of the vehicle, a pair of rear side frames 2 extending in the front-rear direction are provided on the left and right sides. The rear ends of a pair of reinforcing members 3 that gradually extend downwards towards the front are respectively joined to the front ends of the pair of rear side frames 2. The front ends of the pair of reinforcing members 3 are respectively joined to the rear ends of a pair of lower side beams 4 extending in the front-rear direction.

[0037] The front area of ​​the rear floor 5 is joined to a pair of rear side frames 2. The rear floor 5 is composed of a double-plate member structure 10 having an upper plate member 11 and a lower plate member 12, which are arranged opposite each other in the vertical direction and extend to each other in the horizontal direction.

[0038] The upper plate member 11 and the lower plate member 12 are constructed of substantially the same shape, for example, in a form in which a portion is flipped upside down. Therefore, only the upper plate member 11 will be described in the following description, while the lower plate member 12 will be described as needed. In the lower plate member 12, parts constructed in the same way as the upper plate member 11 will be described with the same names and reference numerals as those in the upper plate member 11, as needed.

[0039] The upper plate member 11 and the lower plate member 12 are formed, for example, by plates made of aluminum or the like.

[0040] The upper plate member 11 has: a narrow portion 11a, which is arranged across a pair of rear side frames 2; a front wide portion 11b, which extends rearward from the rear of the narrow portion 11a; and a rear wide portion 11c, which extends further rearward from the rear of the front wide portion 11b.

[0041] Multiple front ridges 13 are formed in the narrow section 11a. Each front ridge 13 extends in the front-rear direction and is arranged in the vehicle width direction. The front ridges 13 are formed such that they protrude from the upper side of the front ridges 13 and are recessed from the lower surface 11d side of the upper plate member 11.

[0042] The front wide section 11b is formed such that its width in the vehicle width direction gradually increases as it moves toward the rear. The rear wide section 11c is formed with the same width in the vehicle width direction as the rear portion of the front wide section 11b.

[0043] Multiple rear-side protrusions 14 are formed in the front wide portion 11b and the rear wide portion 11c. Each rear-side protrusion 14 extends along the vehicle width direction and is arranged in the front-rear direction. The rear-side protrusions 14 protrude from the lower surface 11d of the upper plate member 11 and is recessed on the upper side.

[0044] An upwardly bent flange 19a is formed at the rear end of the upper plate member 11. A downwardly bent flange 19b is formed at the rear end of the lower plate member 12. These flanges 19a and 19b are arranged on the same plane along the left-right and up-down directions. Each flange 19a and 19b overlaps with and engages with the rear plate member 20, which will be described later.

[0045] A front floor 6 is joined to a pair of reinforcing members 3 and a lower side beam 4, the front floor 6 being configured across these reinforcing members 3 and the lower side beam 4 and extending along the shape of the reinforcing members 3 and the lower side beam 4. The front portion of the upper plate member 11 in the rear floor 5 joins the rear portion of the front floor 6. Thus, the rear floor 5 is positioned above the front floor 6. A tire (not shown) is accommodated in a space secured beneath the rear floor 5.

[0046] Additionally, a rear wheel cover 7 is provided on the upper part of the rear side frame 2 and the reinforcing member 3. The lower rear edge of the rear wheel cover 7 is joined to the left and right edges of the front wide portion 11b in the upper plate member 11.

[0047] The outer plate member 8 is joined to the left and right edges of the rear wide portion 11c in the upper plate member 11 and the upper part of the rear wheel cover 7 around the entire circumference.

[0048] Figure 3 yes Figure 1 III-direction view.

[0049] like Figure 1 , Figure 3 As shown, a central frame 15 extending in a straight line along the front-rear direction is provided on the lower surface 11d of the upper plate member 11, in the center of the rear width portion 11c in the vehicle width direction. That is, the central frame 15 is provided between the upper plate member 11 and the lower plate member 12.

[0050] The central frame 15 is formed in a C-shape with an upper opening in its cross-sectional shape along the vehicle width direction. The central frame 15 can be formed, for example, by aluminum extrusion or stamping of a metal sheet. First outwardly projecting flanges 16 are formed on the left and right sides of the central frame 15, bending outwards in the vehicle width direction. These first outwardly projecting flanges 16 overlap and engage with the lower surface 11d of the upper plate member 11. Thus, a closed cross-section is formed by the central frame 15 and the upper plate member 11.

[0051] Additionally, a second outer flange 17 is formed at the rear end 15a of the central frame 15, extending from the periphery of the central frame 15 in the vehicle width direction and downward. The second outer flange 17 overlaps with and is fastened to the rear plate member 20 described later.

[0052] A crossbeam 18 is joined at the front end 15b of the central frame 15. The crossbeam 18 is disposed on the lower surface 11d and the front wide portion 11b of the upper plate member 11. That is, the crossbeam 18 is also disposed between the upper plate member 11 and the lower plate member 12.

[0053] The crossbeam 18 can be manufactured, for example, by aluminum extrusion or stamping of a sheet metal. The crossbeam 18 extends along the vehicle width direction while bending. More specifically, the crossbeam 18 extends obliquely forward as it moves from the central frame 15 toward both outer sides in the vehicle width direction. That is, the crossbeam 18 is a bifurcated shape formed by bending in a rearward-protruding manner when viewed from above. The bent portion 18a of the crossbeam 18 engages with the front end 15b of the central frame 15.

[0054] The left and right ends 18b of the crossbeam 18 are respectively connected to the rear end 2a of the rear side frame 2.

[0055] The crossbeam 18 branches from the front end 15b of the central frame 15 to the rear end 2a of the rear side frame 2, thus forming a shape that is symmetrical about the center in the vehicle width direction.

[0056] The beam 18 is formed in a C-shape with an opening at the top in the cross-sectional shape along the direction orthogonal to the extension direction and in the vertical direction. Thus, the beam 18 and the upper plate member 11 form a closed section.

[0057] Figure 4 This is a partially exploded perspective view of the lower side of the rear structure 1 of the vehicle, viewed from a slightly rearward angle. Figure 4The diagram of the lower plate component 12 is omitted.

[0058] like Figures 2 to 4 As shown, a rear plate member 20 is provided at the rear end of the rear floor 5 (upper plate member 11, lower plate member 12) and the central frame 15. The rear plate member 20 is a metal plate member extending in the left-right and up-down directions. The flanges 19a and 19b of the rear floor 5 (upper plate member 11 and lower plate member 12) are joined to the front surface of the rear plate member 20.

[0059] Additionally, a second outer flange 17 of the central frame 15 overlaps on the front surface of the rear panel member 20. The second outer flange 17 of the central frame 15 causes the rear panel member 20 to overlap with the bumper beam 21 disposed on the rear surface of the rear panel member 20 and to be fastened together by bolts and nuts 22b and 22c (details are described later).

[0060] The bumper beam 21 is formed to extend along the vehicle width direction. The length of the bumper beam 21 in the vehicle width direction is approximately three times the width of the central frame 15 in the vehicle width direction. The bumper beam 21 is positioned at the center of the rear panel member 20 in the vehicle width direction. Therefore, the bumper beam 21 is positioned to overlap with the central frame 15 when viewed from the front-rear direction.

[0061] The bumper beam 21 is formed in a C-shape with a front opening in its cross-sectional shape along the front-rear and vertical directions. In other words, the bumper beam 21 is formed by a rearward bulge on the rear surface of the rear panel member 20, extending from a position corresponding to the upper panel member 11 to a position corresponding to the lower panel member 12. That is, the bumper beam 21 has: an upper wall portion 21a that extends rearward from a position on the rear surface of the rear panel member 20 corresponding to the upper panel member 11; a rear wall portion 21b that extends downward from the rear edge of the upper wall portion 21a; and a lower wall portion 21c that extends forward from the rear wall portion 21b and reaches a position corresponding to the lower panel member 12.

[0062] The bumper beam 21 thus formed can be created, for example, by stamping a metal sheet. It can also be formed by aluminum extrusion molding or similar methods. The bumper beam 21 is configured to be crushed by a load applied from the rear (hereinafter referred to as a rear-end collision load).

[0063] An upper fixing portion 21d is formed on the upper wall portion 21a of the bumper beam 21, bending upward from the front edge. A lower fixing portion 21e is formed on the lower wall portion 21c of the bumper beam 21, bending downward from the front edge. These fixing portions 21d and 21e overlap with the rear surface of the rear panel member 20.

[0064] The position of the upper fixing part 21d is offset upwards compared to the position of the flange part 19a of the upper plate member 11. The position of the lower fixing part 21e is offset upwards compared to the position of the flange part 19b of the lower plate member 12.

[0065] The upper fixing part 21d of the bumper beam 21 configured in this way is fastened to the rear panel member 20 by four bolts and nuts 22a to 22d. The four bolts and nuts 22a to 22d are evenly spaced along the vehicle width direction. The lower fixing part 21e is also fastened to the rear panel member 20 by four bolts and nuts 22a to 22d.

[0066] Two of the four bolts-nuts 22a to 22d used to fasten the lower fixing part 21e, located at the center in the vehicle width direction, are arranged at a position overlapping with the second outer flange 17 of the central frame 15 in the longitudinal direction. Thus, the second outer flange 17 of the central frame 15, the rear panel member 20, and the bumper beam 21 overlap at the same position and are tightened together by two bolts-nuts 22b and 22c respectively. The bumper beam 21 is connected to the central frame 15 via the rear panel member 20. It should be noted that a rear bumper, which extends integrally in the vehicle width direction behind the bumper beam 21, is an external component; this is not shown in the diagram.

[0067] <The function of the rear structure of a vehicle>

[0068] Next, based on Figure 2 , Figure 3 To explain the function of the rear structure 1 of the vehicle.

[0069] When a rear-end collision load F1 is applied to the rear structure 1 of the vehicle, the rear-end collision load F1 is first applied to the bumper beam 21. Here, a central frame 15 is positioned in front of the bumper beam 21. The central frame 15 extends in a straight line in the longitudinal direction, thus easily ensuring the mechanical strength of the central frame 15. Therefore, the forward displacement of the bumper beam 21 is restricted by the central frame 15. As a result, the bumper beam 21 is crushed while simultaneously bearing the rear-end collision load F1. In other words, the rear-end collision load F1 is absorbed by the bumper beam 21 as it is crushed.

[0070] Additionally, while the rear-end collision load F1 is borne by the bumper beam 21, this load is also transferred to the central frame 15. Consequently, the central frame 15 also bears the rear-end collision load F1. A crossbeam 18 is joined to the front end 15b of the central frame 15. The crossbeam 18 is bifurcated. Furthermore, the left and right ends 18b of the crossbeam 18 are respectively joined to the rear end 2a of the rear side frame 2. Therefore, the rear-end collision load F1 is transferred to the crossbeam 18 via the central frame 15 (see reference). Figure 3(See arrow Y1 in the image). Furthermore, the rearward collision load F1 is distributed to the left and right rear side frames 2 via the crossbeam 18 (see reference). Figure 3 (Arrow F2 in the image).

[0071] The crossbeam 18 is symmetrical about the center in the vehicle width direction, thus easily distributing the rear impact load F1 borne by the central frame 15 to the left and right rear side frames 2 equally. Furthermore, the crossbeam 18 extends at an angle that gradually moves forward from the central frame 15 towards the outer sides in the vehicle width direction. Therefore, the rear impact load F1 borne by the central frame 15 can be easily transferred to the left and right rear side frames 2 via the crossbeam 18.

[0072] Furthermore, since the bumper beam 21 is mounted on the rear surface of the rear panel member 20, the rear impact load F1 applied to the bumper beam 21 is also transmitted to the rear panel member 20. Moreover, the rear impact load F1 is also transmitted to the rear floor 5 (upper panel member 11, lower panel member 12) via the rear panel member 20.

[0073] Here, the upper fixing portion 21d of the bumper beam 21 is positioned upwards compared to the position of the flange portion 19a of the upper plate member 11. The lower fixing portion 21e is positioned upwards compared to the position of the flange portion 19b of the lower plate member 12. Therefore, the rearward impact load F1 applied to the bumper beam 21 is not easily and efficiently transmitted directly to each plate member 11, 12. On the other hand, the second outer flange portion 17 of the central frame 15 overlaps with the lower fixing portion 21e of the bumper beam 21 in the longitudinal direction. As a result, the rearward impact load F1 is preferentially transmitted to the central frame 15 compared to each plate member 11, 12.

[0074] Regarding the rearward collision load F1 applied to each plate member 11, 12, each plate member 11, 12 operates as follows: Multiple rearward protrusions 14 extending along the vehicle width direction are formed on the front width portion 11b and the rear width portion 11c of each plate member 11, 12. Therefore, the front width portion 11b and the rear width portion 11c have weaker mechanical strength relative to loads received from the left-right direction compared to loads received from the front-rear direction.

[0075] In contrast, each plate member 11, 12 has a plurality of front protrusions 13 extending in the front-rear direction in the narrow portion 11a. Therefore, the mechanical strength of the narrow portion 11a against loads borne in the front-rear direction is stronger than that of the front wide portion 11b and the rear wide portion 11c against loads borne in the front-rear direction.

[0076] As a result, when a rearward impact load F1 is applied to each of the plate members 11 and 12, the front wide portion 11b and the rear wide portion 11c deform more actively than the narrow portion 11a. Due to this deformation, the rearward impact load F1 is absorbed by the front wide portion 11b and the rear wide portion 11c, and the rearward impact load F1 is less likely to be transmitted to a position further forward than the narrow portion 11a.

[0077] Thus, the aforementioned rear structure 1 of the vehicle includes: a central frame 15; and a bumper beam 21, which is arranged behind the central frame 15 and positioned to overlap with the central frame 15 when viewed from the front-rear direction. Therefore, from the instant a rear-impact load F1 is applied to the bumper beam 21, the bumper beam 21 can reliably collapse to absorb the rear-impact load F1, while the central frame 15 bears the rear-impact load. Consequently, the peak load of the rear-impact load F1 can be suppressed, and the rear-impact load F1 can be absorbed efficiently.

[0078] Figure 5 This is a line graph showing the variation of the rear collision load in the rear structure 1 of the vehicle, with the vertical axis set to the magnitude of the rear collision load [f] and the horizontal axis set to the deformation stroke [s] of the rear structure 1 of the vehicle. Figure 5 The enclosed region R is equivalent to absorbing energy from rear-end collision loads. Figure 5 The area shown by the double-dotted lines illustrates the variation in rear-impact loads in a conventional structure (see Patent Document 1) for comparison. For example... Figure 5 As shown, in the aforementioned rear structure 1 of the vehicle, the bumper beam 21 can reliably collapse and absorb the rear collision load F1 from the instant the rear collision load F1 is applied to it. Therefore, it can be confirmed that, compared with conventional structures, peak loads are suppressed and rear collision loads are absorbed efficiently.

[0079] Furthermore, a bumper beam 21 is positioned directly behind the central frame 15. Therefore, even if the input position of the rear collision load F1 is slightly offset from the center in the vehicle width direction, the rear collision load F1 is first transmitted to the central frame 15. Consequently, the rear structure 1 of the vehicle will not bear the rear collision load F1 unbalancedly from left to right, and thus can stably absorb the rear collision load F1.

[0080] A rear panel member 20 is provided between the central frame 15 and the bumper beam 21. The bumper beam 21 is connected to the central frame 15 via the rear panel member 20. Therefore, the rear impact load F1 applied to the bumper beam 21 can also be transferred to the rear panel member 20. In this way, the rear impact load F1 applied to the bumper beam 21 can be distributed to the rear panel member 20 in addition to the central frame 15. Therefore, the rear impact load F1 will not concentrate on any specific component of the vehicle 100 other than the bumper beam 21. As a result, damage to the vehicle 100 from the rear impact load F1 can be reliably suppressed.

[0081] The vehicle includes a crossbeam 18 that engages with the front end 15b of the central frame 15. Additionally, it includes rear side frames 2 that engage with the left and right ends 18b of the crossbeam 18. Therefore, the rear impact load F1 can be transferred to the crossbeam 18 via the central frame 15, and further transferred to the rear side frames 2 located on both sides in the vehicle width direction. By transferring the rear impact load F1 evenly to both rear side frames 2 via the central frame 15, the rear impact load F1 can be evenly distributed to both rear side frames 2. Figure 3 The rear collision load F2 in the middle). Therefore, it is possible to more reliably suppress the damage to vehicle 100 caused by the rear collision load F1.

[0082] The crossbeam 18 extends at an angle that gradually moves forward from the central frame 15 toward the outer sides in the vehicle width direction. Therefore, compared to the case where the crossbeam 18 extends in a straight line in the vehicle width direction, it is easier to transfer the rear collision load F1 transmitted from the central frame 15 to the rear side frame 2, which is located in front of the crossbeam 18.

[0083] The central frame 15 extends in a straight line in the longitudinal direction. Therefore, compared to a case where the central frame 15 is bent, the rearward collision load F1 applied to the central frame 15 can be reliably transferred to the crossbeam 18. Consequently, the rearward collision load can be reliably distributed to the entire rear of the vehicle 100.

[0084] The second outer flange 17 of the central frame 15, the rear panel member 20, and the bumper beam 21 are fastened together at the same location by two bolts and nuts 22b and 22c. Therefore, the rear impact load F1 applied to the bumper beam 21 can be efficiently distributed and transferred to the central frame 15 and the rear panel member 20.

[0085] The rear floor 5 is composed of a double-plate structure 10 having an upper plate member 11 and a lower plate member 12. The upper plate member 11 and the lower plate member 12 are arranged opposite each other in the vertical direction and extend to each other in the horizontal direction. Therefore, the rearward impact load F1 applied to the rear floor 5 can be dispersed to the upper plate member 11 and the lower plate member 12. Furthermore, the rearward impact load F1 applied to each plate member 11, 12 can be minimized.

[0086] Multiple rearward protrusions 14 extending along the vehicle width direction are formed on the front wide portion 11b and the rear wide portion 11c of each plate member 11 and 12. Therefore, when a rearward collision load F1 is applied to each plate member 11 and 12, the front wide portion 11b and the rear wide portion 11c can deform more actively than the narrow portion 11a, and the rearward collision load F1 can be absorbed by the front wide portion 11b and the rear wide portion 11c. Therefore, the rearward collision load F1 is less likely to be transmitted forward compared to the narrow portion 11a.

[0087] The positions of the fixing portions 21d and 21e in the bumper beam 21 are offset upwards relative to the positions of the flange portions 19a and 19b in the corresponding plate members 11 and 12, respectively. Therefore, the rear impact load F1 applied to the bumper beam 21 can be suppressed from being directly and efficiently transmitted to the plate members 11 and 12.

[0088] In contrast, the second outer flange 17 of the central frame 15 overlaps with the lower fixing portion 21e of the bumper beam 21 in the longitudinal direction. Therefore, it can preferentially transfer the rearward collision load F1 to the central frame 15 compared to the individual plate members 11, 12. As a result, the function of the central frame 15 can be fully utilized.

[0089] Furthermore, the positions of the fixing portions 21d and 21e in the bumper beam 21 are offset upwards relative to the positions of the flange portions 19a and 19b in the corresponding plate members 11 and 12. Therefore, when the central frame 15, bumper beam 21, rear plate member 20, and each plate member 11 and 12 are integrated, the following effect is achieved: For example, if spot welding is used when fixing the central frame 15, bumper beam 21, rear plate member 20, and each plate member 11 and 12, it is possible to avoid completely overlapping and spot welding the aforementioned central frame 15, bumper beam 21, rear plate member 20, and each plate member 11 and 12. Therefore, it is possible to suppress the reduction in strength caused by spot welding.

[0090] [Variation Example]

[0091] It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications to the above-described embodiments without departing from the spirit of the present invention.

[0092] For example, in the embodiment described above, the crossbeam 18 is shown to extend in an inclined manner, gradually moving forward from the central frame 15 towards both outer sides in the vehicle width direction. However, it is not limited to this; the crossbeam 18 may be connected to the front end 15b of the central frame 15 and to the rear end 2a of the rear side frame 2. Specific variations of the crossbeam 18 will be described below.

[0093] Figure 6 This is a plan view of the rear structure 1 of the vehicle, showing a modified example of the crossbeam 18, viewed from below. Figure 6 With the aforementioned Figure 3 correspond.

[0094] like Figure 6 As shown, the crossbeam 18 extends in a straight line along the vehicle width direction. The left and right ends 18b of the crossbeam 18 are respectively connected to the rear ends 2a of the rear side frame 2.

[0095] The central frame 15 extends in the longitudinal direction from the rear end of the rear floor 5 (the flanges 19a and 19b of each plate member 11 and 12) to the crossbeam 18. The front end 15b of the central frame 15 joins the central portion 18c of the crossbeam 18 in the vehicle width direction.

[0096] Therefore, the above-described variations achieve the same effect as the aforementioned implementation method.

[0097] Furthermore, in the above embodiment, the positions of the fixing portions 21d and 21e in the bumper beam 21 are described as being offset upwards relative to the positions of the flange portions 19a and 19b in the corresponding plate members 11 and 12. However, this is not a limitation; the positions of the fixing portions 21d and 21e in the bumper beam 21 may also be offset downwards relative to the positions of the flange portions 19a and 19b in the corresponding plate members 11 and 12.

[0098] In the above embodiments, the rear floor 5 is described as follows: it is composed of a double-plate member structure 10 having an upper plate member 11 and a lower plate member 12, the upper plate member 11 and the lower plate member 12 being arranged opposite each other in the vertical direction and extending from each other in the horizontal direction. However, it is not limited to this, and the rear floor 5 may be composed of only either the upper plate member 11 or the lower plate member 12. Alternatively, the double-plate member structure 10 may be formed by extruding aluminum.

[0099] In the above embodiment, the case where the rear plate member 20 is joined to the rear end portion 15a (second outer flange portion 17) of the central frame 15 is described. However, it is not limited to this, and the rear plate member 20 may be joined to the rear portion of the central frame 15. That is, the rear plate member 20 may not be joined at the end (rear end portion 15a) of the central frame 15, but rather at a position slightly forward of that end (rear end portion 15a). In this case, the rear portion of the central frame 15 slightly extends through the rear plate member 20.

[0100] In the above embodiment, the case where a crossbeam 18 is joined at the front end 15b of the central frame 15 is described. However, it is not limited to this; it is sufficient for the crossbeam 18 to be joined at the front of the central frame 15. That is, the crossbeam 18 may not be joined at the exact end (front end 15b) of the central frame 15, but rather at a position slightly forward of that end (front end 15b). In this case, the front of the central frame 15 is slightly inserted into the crossbeam 18.

[0101] In the above embodiment, the case where the left and right ends 18b of the crossbeam 18 are joined to the rear end 2a of the rear side frame 2 is described. However, it is not limited to this; the crossbeam 18 can be joined to the rear of the rear side frame 2. That is, the crossbeam 18 may not be joined at the end (rear end 2a) of the rear side frame 2, but rather at a position slightly forward of that end (rear end 2a). In this case, the left and right ends 28b of the crossbeam 18 are slightly inserted into the rear side frame 2.

[0102] In the above embodiment, the length of the bumper beam 21 in the vehicle width direction is described as approximately three times the width of the central frame 15 in the vehicle width direction. However, it is not limited to this, and the bumper beam 21 can be arranged behind the central frame 15 and overlap with the central frame 15 when viewed from the front-rear direction.

Claims

1. A rear structure for a vehicle, characterized in that, The rear structure of the vehicle includes: The central frame is located on both sides of the vehicle in the width direction, near the center of the vehicle in the width direction, and extends along the front-rear direction of the vehicle. A bumper beam is arranged behind the central frame and positioned to overlap with the central frame when viewed from the front-rear direction. The bumper beam is capable of being crushed by a rear-end collision load. It becomes the exterior rear bumper, which is located on the rear side of the bumper beam; Rear floor, which is disposed at the rear of the vehicle; and A rear panel member extends in both left-right and up-down directions between the central frame and the bumper beam, and is located at the rear end of the rear floor and the central frame. The bumper beam has the following features: Upper wall; and The lower wall portion is located below the upper wall portion. An upper fixing part is formed in the upper wall portion. A lower fixing part is formed in the lower wall portion. The upper fixing part and the lower fixing part are fixed to the rear surface of the rear plate component. The bumper beam is connected to the central frame via the rear panel member.

2. The vehicle rear structure according to claim 1, characterized in that, have: A crossbeam, positioned in front of the central frame and extending along the vehicle width direction; and Side frames, which are located on both sides in the vehicle width direction. The front part of the central frame is connected to the crossbeam, and the two ends of the crossbeam in the vehicle width direction are respectively connected to the rear part of the side frame.

3. The vehicle rear structure according to claim 2, characterized in that, The crossbeam extends at an angle that gradually moves forward from the central frame toward the outer sides in the vehicle width direction.

4. The vehicle rear structure according to claim 3, characterized in that, The central frame extends in a straight line in the front-to-back direction.

5. The vehicle rear structure according to claim 1, characterized in that, The central frame, the bumper beam, and the rear panel component are fixed in the same position.

6. The vehicle rear structure according to claim 1, characterized in that, The rear floor is composed of a double-plate structure having an upper plate member and a lower plate member disposed below the upper plate member. The central frame is provided on the lower surface of the upper plate component.

7. The vehicle rear structure according to claim 6, characterized in that, The bumper beam is formed by bending rearward in a manner that bulges outward from the upper plate member to the lower plate member. The upper fixing part of the bumper beam is offset in the vertical direction relative to the rear end of the upper plate member. The lower fixing part of the bumper beam is offset in the vertical direction relative to the rear end of the lower plate member.

8. A rear structure of a vehicle, characterized in that, The rear structure of the vehicle includes: The central frame is located on both sides of the vehicle in the width direction, near the center of the vehicle in the width direction, and extends along the front-rear direction of the vehicle. A bumper beam is arranged behind the central frame and positioned to overlap with the central frame when viewed from the front-rear direction. The bumper beam is capable of being crushed by a rear-end collision load. as well as The rear floor, which is located at the rear of the vehicle, The rear floor is composed of a double-plate structure having an upper plate member and a lower plate member disposed below the upper plate member. The central frame is provided on the lower surface of the upper plate component. The bumper beam is formed by bending rearward in a manner that bulges outward from the upper plate member to the lower plate member. The upper fixing part of the bumper beam is offset in the vertical direction relative to the rear end of the upper plate component. The lower fixing part of the bumper beam is offset in the vertical direction relative to the rear end of the lower plate component.

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