Vehicle rear structure

Abstract

To provide a rear structure of a vehicle which can improve collision energy absorption amount upon a rear collision without increasing cost and mass.SOLUTION: A rear structure of a vehicle includes: a pair of right and left rear frames 21, 22 which extends in a vehicle longitudinal direction and has a compressive deformation region α which is compressed and deformed by receiving a collision load in a longitudinal direction at a rear end; a floor panel 5 which is positioned between the pair of right and left rear frames 21, 22 in a vehicle width direction of the rear frames 21, 22; and a pair of right and left energy absorption members 30 which extends in the longitudinal direction, receives the collision load in the longitudinal direction and is compressed and deformed. The energy absorption member 30 is provided in an upper section of the rear frames 21, 22 and in the compressive deformation region α.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a rear structure of a vehicle, and more particularly to a rear structure of a vehicle that includes a pair of left and right rear frames that extend in the fore-and-aft direction of the vehicle and receive rear-end collision loads, and a floor panel located between these left and right rear frames in the vehicle width direction. [Background technology]

[0002] BACKGROUND ART A structure is known in which the rear floor panel between a pair of left and right rear side frames (rear frames) is strengthened to improve the amount of energy absorbed during a rear collision.

[0003] That is, as disclosed in Patent Document 1, a luggage compartment recess is provided in a rear floor panel located between a pair of left and right rear side frames in the vehicle width direction, and the luggage compartment recess is formed from a metal plate having a tensile strength equal to or greater than that of the pair of left and right rear side frames, for example, a steel plate having a tensile strength of 590 MPa or 780 MPa.

[0004] To further improve energy absorption in comparison with conventional structures, a structure in which an energy absorbing member is attached to the rear floor panel, etc., can be considered. In this case, there is a risk that the energy absorbing member will impede the compressive behavior of the rear side frame, and problems arise such as an increase in the overall functional load of the vehicle, which in turn increases cost and mass. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Republished Patent No. WO2017 / 119472 Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rear structure for a vehicle that can improve the amount of collision energy absorption during a rear collision without increasing costs or mass. [Means for solving the problem]

[0007] The present invention provides a vehicle having a pair of left and right rear frames extending in the longitudinal direction of the vehicle and having compressive deformation regions at their rear ends that undergo compressive deformation when subjected to a longitudinal collision load, a floor panel located between the pair of left and right rear frames in the vehicle width direction, and a pair of left and right energy absorbing members extending in the longitudinal direction and that undergo compressive deformation when subjected to a longitudinal collision load, the energy absorbing members being provided on top of the rear frames and in at least the compressive deformation regions. The energy absorbing member has a fixed portion at the front that is fixed to the vehicle body and a non-contact portion at the rear that is not fixed to the vehicle body, and the lower surface of the non-contact portion is located above and spaced apart from the upper surface of the rear frame. The rear structure of a vehicle is characterized by the following.

[0008] The compressive deformation region refers to the region between the rear end of the rear wheel house and the rear end panel. The rear frame may be a rear side frame. The floor panel may be a rear floor panel.

[0009] According to this invention, the energy absorbing member is provided on the upper part of the rear frame and at least in the compressive deformation area, so that when the rear end of the rear frame receives a longitudinal collision load during a rear collision, the compressive deformation behavior of the rear frame can be maintained.

[0010] Furthermore, since the energy absorbing member is provided in the upper part of the rear frame and in the compressive deformation region, the energy absorbing member can undergo compressive deformation without adversely affecting the deformation behavior of the rear frame, thereby improving the amount of energy absorption. In short, according to the present invention, it is possible to improve the amount of collision energy absorption during a rear-end collision without increasing costs or mass.

[0011] As described above, the energy absorbing member has a portion at the front that is fixed to the vehicle body, and a non-contact portion at the rear that is not fixed to the vehicle body. As a result, the rear portion of the energy absorbing member has a non-contact portion that is not fixed to the vehicle body, so that the energy absorbing member does not hinder axial compression of the rear frame in the event of a rear-end collision of the vehicle, thereby improving the amount of energy absorption.

[0012] Furthermore, as described above, the lower surface of the non-contact portion is located above and spaced apart from the upper surface of the rear frame. As a result, the lower surface of the non-contact portion is floating above the upper surface of the rear frame, so that when the rear portion of the rear frame is axially compressed during a rear-end collision of the vehicle, even if the rear portion of the rear frame deforms like a bellows, this is not hindered by the energy absorbing member, and the amount of energy absorption can be improved.

[0013] As an aspect of the present invention, the energy absorbing member may support a luggage compartment member that forms the lower surface of the luggage compartment. The luggage compartment member may be a trunk board. According to the present invention, the energy absorbing member supports the luggage compartment member, so that the support member conventionally provided in the sub-trunk can be eliminated while improving the amount of energy absorption.

[0014] In addition, as an aspect of the present invention, the upper surfaces of the pair of left and right energy absorbing members may be configured to be at the same height on the left and right when assembled to the vehicle, and the upper surfaces of the energy absorbing members may be located at a position higher than the upper surface of a spare tire provided in a sub-trunk below the luggage compartment member. According to this invention, the pair of left and right energy absorbing members function as trunk board support members, and the support performance of the luggage compartment members can be reliably exhibited.

[0015] Furthermore, as an aspect of the present invention, the rear end of the fixing portion may be located forward of the rear end of the rear wheel housing. According to this invention, by not providing the fixing portion behind the rear wheel house where the rear frame can be axially compressed, it is possible to achieve both axial compression of the energy absorbing member and axial compression of the rear frame.

[0016] Additionally, as an aspect of the present invention, the energy absorbing member may be configured so that the rigidity increases toward the front of the vehicle at least in the compressive deformation region. According to this invention, the front side of the energy absorbing member of the vehicle is made highly rigid, thereby supporting the energy absorbing member, and thereby allowing the energy absorbing member to stably undergo axial compressive deformation from its rear end in the event of a rear collision.

[0017] In another aspect of the present invention, the energy absorbing member may have longitudinal ribs and transverse ribs in its cross section. According to the present invention, the amount of energy absorbed by the energy absorbing member can be further improved by the above-mentioned ribs.

[0018] Furthermore, as an aspect of the present invention, a rear end panel may be provided at the rear of the rear frame, and a position control member may be provided on the rear end panel to control the movement of the rear end of the energy absorbing member in the vertical and transverse directions of the vehicle.

[0019] According to this invention, the position restricting member restricts the movement of the rear end of the energy absorbing member in the vertical direction and the vehicle width direction, thereby suppressing bending of the energy absorbing member and promoting axial compression of the energy absorbing member. Incidentally, if the energy absorbing member is broken, the axial compression of the energy absorbing member is hindered, and the amount of energy absorption is significantly reduced, which is undesirable.

[0020] Furthermore, as an aspect of the present invention, the position restriction member may be substantially inverted U-shaped with an opening that opens downward, and the rear end of the energy absorbing member may be inserted into the opening. According to the present invention, by adding a simple structure, it is possible to achieve the effect of suppressing the breakage of the energy absorbing member and the effect of promoting axial compression of the energy absorbing member.

[0021] Additionally, as an aspect of the present invention, the energy absorbing member may have a rectangular cross section, and a notch may be provided at the rear end of the energy absorbing member to cut out a ridgeline of the rectangular shape. According to this invention, by cutting out the ridge line to form a notch, stress is concentrated in the notch, which becomes the trigger for compressive deformation, allowing the energy absorbing member to be compressed and deformed from its rear end more stably in the event of a rear-end collision. [Effects of the Invention]

[0022] According to the present invention, it is possible to improve the amount of collision energy absorbed in the event of a rear-end collision without increasing the cost or mass. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a top perspective view showing the rear structure of the vehicle. [Figure 2]2 is a top perspective view showing the rear structure of the vehicle with a luggage compartment member removed from FIG. 1. FIG. [Figure 3] 3 is a top perspective view showing the rear structure of the vehicle with the energy absorbing member removed from FIG. 2. FIG. [Figure 4] Cross-sectional view taken along line AA in Figure 1. [Figure 5] BB line cross-sectional view of FIG. 1. [Figure 6] FIG. 5 is a top perspective view of FIG. [Figure 7] FIG. 2 is a plan view showing the rear structure of the vehicle on the right side of the vehicle. [Figure 8] FIG. 10 is a perspective view showing a position restriction structure using a position restriction member. [Figure 9] 8 is a cross-sectional view taken along line CC in FIG. 7. [Figure 10] DD line cross-sectional view of FIG. 7. [Figure 11] 8 is a cross-sectional view taken along line EE in FIG. 7. [Figure 12] FIG. 2 is a schematic side view showing a state of the vehicle before a rear collision load is input; [Figure 13] FIG. 10 is a schematic side view showing the state of a vehicle equipped with an energy absorbing member during a rear collision. [Figure 14] 10 is a schematic side view showing a state of a vehicle in a rear collision when an energy absorbing member and a position restricting member are provided; FIG. [Figure 15] FIG. 4 is a characteristic diagram showing a change in load with respect to the elapsed time from a rear-end collision. DETAILED DESCRIPTION OF THE INVENTION

[0024] The objective of improving the amount of collision energy absorbed during a rear collision without increasing cost or mass is achieved by a configuration comprising a pair of left and right rear frames that extend in the fore-and-aft direction of the vehicle and have compressive deformation regions at their rear ends that undergo compressive deformation when subjected to a fore-and-aft collision load, a floor panel located between the pair of left and right rear frames in the vehicle width direction, and a pair of left and right energy absorbing members that extend in the fore-and-aft direction and undergo compressive deformation when subjected to a fore-and-aft collision load, the energy absorbing members being provided on top of the rear frames and in at least the compressive deformation regions. [Example]

[0025] An embodiment of the present invention will be described in detail below with reference to the drawings. The drawings show the rear structure of a vehicle, with Fig. 1 being a top perspective view showing the rear structure of the vehicle, Fig. 2 being a top perspective view showing the rear structure of the vehicle with a luggage compartment member removed from Fig. 1, and Fig. 3 being a top perspective view showing the rear structure of the vehicle with an energy absorbing member removed from Fig. 2. All of Figs. 1 to 3 show the rear structure of the vehicle as seen from above and in front of the vehicle.

[0026] 4 is a cross-sectional view taken along line AA in FIG. 1, FIG. 5 is a cross-sectional view taken along line BB in FIG. 1, FIG. 6 is a top perspective view of FIG. 4, FIG. 7 is a plan view showing the rear structure of the vehicle on the right side of the vehicle, and FIG. 8 is a perspective view showing the position regulation structure of the energy absorbing member by the position regulation member.

[0027] Furthermore, Fig. 9 is a cross-sectional view taken along line CC in Fig. 7, Fig. 10 is a cross-sectional view taken along line DD in Fig. 7, Fig. 11 is a cross-sectional view taken along line EE in Fig. 7, and Fig. 12 is a schematic side view showing the state of the vehicle before a rear-impact load is input (when no collision occurs). Note that the rear structure of the vehicle in the embodiments described below is configured to be symmetrical or approximately symmetrical.

[0028] As shown in Figure 12, there is a front floor panel 2 that forms the floor surface of the vehicle interior 1, and a kick-up portion 3 that rises upward from the rear end of the front floor panel 2. A rear seat pan 4 is provided that extends rearward from the upper end of the kick-up portion 3.

[0029] As shown in Figures 12 and 4, a rear floor panel 5 is integrally or integrally connected to the rear of the rear seat pan 4. A luggage compartment recess 6 is formed in a downwardly stepped position at the middle of the rear floor panel 5 in the longitudinal and transverse directions, as shown in Figures 2, 3 and 5.

[0030] As shown in FIG. 5, a sub-trunk 7 is formed between the rear floor panel 5 including the above-mentioned luggage compartment recess 6 and a trunk board 40 serving as a luggage compartment member, which will be described later. This sub-trunk 7 is configured to store, for example, a jack and other tools, or a spare tire 8 (see FIG. 5).

[0031] As shown in FIG. 4, a rear end panel 9 extending in the vertical direction of the vehicle is joined and fixed to a bent portion 5a formed by bending upward at the rear end of the rear floor panel 5 described above, and a rear end member 10 is joined and fixed to the upper front portion of this rear end panel 9.

[0032] As shown in Figure 4, the rear end member 10 has an upper wall 10a, a front wall 10b, a lower wall 10c, and upper and lower joining flange portions 10d, 10e. By joining and fixing the upper and lower joining flange portions 10d, 10e to corresponding portions of the rear end panel 9, a rear end closed cross section 11 extending in the vehicle width direction is formed between the rear end member 10 and the rear end panel 9.

[0033] As shown in FIG. 5, reinforcements 12 are interposed between the rear end member 10 and the rear end panel 9 on the side portions of the rear end panel 9 and the rear end member 10 in the vehicle width direction.

[0034] As shown in Figure 4, an upper cross member 13 and a lower cross member 14 are joined to both the upper and lower surfaces of the front portion of the rear floor panel 5, and a cross member closed cross section 15 extending in the vehicle width direction is formed between the upper cross member 13 and the front upper surface of the rear floor panel 5. In addition, a cross member closed cross section 16 extending in the vehicle width direction is also formed between the lower cross member 14 and the front lower surface of the rear floor panel 5.

[0035] 1 to 3, 6, and 9, a pair of left and right rear wheel houses 17, 17 are provided on both sides in the vehicle width direction of the rear floor panel 5, via a rear side frame upper 21 and a rear side frame lower 22, which will be described later. The rear wheel houses 17 are spaced apart from the rear wheels 18 shown in FIG. 12 and surround the upper sides of the rear wheels 18.

[0036] 1 to 3 and 5, reinforcing members 19 having a generally L-shape in front view of the vehicle are provided to connect the vehicle width direction outer portions of the left and right cross member uppers 13 with the inner wall portions of the left and right rear wheel houses 17. A closed cross section 20 that is continuous in a generally L-shape in front view of the vehicle is formed between the reinforcing members 19 and the inner wall portions of the rear wheel houses 17, and between the reinforcing members 19 and the vehicle width direction outer portions of the cross member uppers 13. The reinforcing member 19 described above is configured to improve the support rigidity of the rear wheel house 17 and to prevent the rear wheel house 17 from collapsing inward.

[0037] 3 and 9, a rear side frame upper 21 is provided that extends in the longitudinal direction of the vehicle by connecting the upper surface of the outer end of the rear floor panel 5 in the vehicle width direction to the lower end of the inner wall of the rear wheel house 17. In addition, a rear side frame lower 22 is provided that extends in the longitudinal direction of the vehicle by connecting the lower surface of the outer end of the rear floor panel 5 in the vehicle width direction to the lower end of the inner wall of the rear wheel house 17.

[0038] As shown in Figure 9, the outer end of the rear floor panel 5 in the vehicle width direction is sandwiched and fixed from above and below by the flange 21a on the inner side of the rear side frame upper 21 in the vehicle width direction and the flange 22a on the inner side of the rear side frame lower 22 in the vehicle width direction.

[0039] As shown in the figure, a flange 21b extending in the vertical direction is provided on the outer side of the rear side frame upper 21 in the vehicle width direction, and a flange 22b extending in the vertical direction is provided on the outer side of the rear side frame lower 22 in the vehicle width direction. These flanges 21b, 22b are joined and fixed to the lower end of the inner wall of the rear wheel house 17 by three-piece welding, and a rear side closed cross section 23 extending in the front-to-rear direction of the vehicle is formed between the rear side frame upper 21 and the rear side frame lower 22.

[0040] 10 and 11, however, at the rear of the upper rear side frame 21 and the lower rear side frame 22, the flanges 21b, 22b extend in the vehicle width direction, and the outer flanges 21b, 22b in the vehicle width direction sandwich and fix the inner end of the rear floor side panel 24 from above and below. As shown in FIG. 7, the rear floor side panel 24 is a panel member that connects the rear wall of the rear wheel house 17 and the rear end panel 9 in the front-to-rear direction of the vehicle.

[0041] As shown in Figures 3 and 5, in this embodiment, the above-mentioned rear side frame upper 21 is composed of three members: a frame upper front portion 21A, a frame upper middle portion 21B, and a frame upper rear portion 21C; however, the rear side frame upper 21 may also be composed of a single, undivided member.

[0042] As shown in Figures 4 and 5, the rear side frame lower 22 is provided with a plurality of beads 22c, 22d, 22e, 22f, 22g, 22h, and 22i spaced apart in the longitudinal direction of the vehicle for inducing crushing in the event of a rear-end collision.

[0043] The pair of left and right rear side frames consisting of the above-mentioned rear side frame upper 21 and rear side frame lower 22 have a compressive deformation region α at their rear end that is compressively deformed when subjected to a collision load in the fore-and-aft direction of the vehicle (i.e., a rear impact load).

[0044] As shown in FIG. 4, the above-mentioned compression deformation region α corresponds to the range in the vehicle longitudinal direction from the rear end portion 17a of the rear wheel house 17 (the rear end portion excluding the flange portion) to the rear end panel 9, and this compression deformation region α is configured so that three beads 22c, 22d, and 22e out of the above-mentioned plurality of beads 22c to 22i are located therein.

[0045] As shown in FIG. 3, the rear floor panel 5 is a floor panel located between a pair of left and right rear side frames (upper rear side frame 21, lower rear side frame 22) in the vehicle width direction.

[0046] As shown in FIG. 4, a rear cross member 25 is provided in the vehicle longitudinal intermediate portion between the cross member lower 14 and the rear end panel 9 to connect the pair of left and right rear side frame lowers 22 in the vehicle width direction.

[0047] This rear cross member 25 extends in the vehicle width direction along the lower part of the rear floor panel 5, which includes the luggage compartment recess 6, and a rear cross closed section 26 extending in the vehicle width direction is formed between the rear cross member 25, the luggage compartment recess 6, and the rear floor panel 5.

[0048] 4 and 5, a pair of left and right energy absorbing members 30 that extend in the vehicle longitudinal direction and undergo compressive deformation when subjected to a collision load in the longitudinal direction (i.e., a rear-impact load) are provided on the upper part of the above-mentioned rear side frame upper 21. The energy absorbing members 30 are provided to include the above-mentioned compressive deformation region α.

[0049] In this embodiment, the energy absorbing member 30 is made of synthetic resin that is useful for absorbing energy, such as PP (polypropylene) or PC (polycarbonate), but is not limited to PP and PC. As shown in FIG. 5, the front end of the energy absorbing member 30 abuts against the rear vertical wall of the reinforcing member 19 that connects the upper cross member 13 and the rear wheel house 17.

[0050] By providing the above-mentioned energy absorbing member 30 on the upper part of the rear side frame upper 21 and at least in the compressive deformation region α, when the rear end parts of the rear side frame upper 21 and the rear side frame lower 22 receive a collision load in the longitudinal direction of the vehicle during a rear collision of the vehicle, the energy absorbing member 30 is configured to maintain the compressive deformation behavior of these rear side frames without interfering with the compressive deformation of the rear side frame upper 21 and the rear side frame lower 22.

[0051] Furthermore, since the energy absorbing member 30 is provided on the upper part of the rear side frame upper 21 and includes the compressive deformation region α, the energy absorbing member 30 can undergo compressive deformation without adversely affecting the deformation behavior of the rear side frame upper 21 and the rear side frame lower 22, thereby improving the amount of energy absorption. In short, the present invention is designed to improve the amount of collision energy absorbed in the event of a rear-end collision without increasing costs or mass.

[0052] As shown in FIGS. 4, 5, 9 and 10, the energy absorbing member 30 supports a flat trunk board 40 serving as a luggage compartment member that constitutes the lower surface of the luggage compartment 27. In this way, the above-mentioned energy absorbing member 30 supports the trunk board 40, thereby improving the amount of energy absorption while eliminating the support member provided on the sub-trunk in the conventional structure.

[0053] Furthermore, as shown in Figures 7 and 9, the above-mentioned energy absorbing member 30 has a fixed portion β1 at its front that is fixed to the vehicle body, and as shown in Figures 7 and 10, has a non-contact portion β2 at its rear that is not fixed to the vehicle body.

[0054] As shown in FIG. 9, the fixed portion β1 of the energy absorbing member 30 is configured by a pair of inner and outer support legs 31, 32 that extend downward from the lower portion of the energy absorbing member 30 and extend in the vehicle longitudinal direction. 9, the support leg 31 on the inner side in the vehicle width direction is fixed to the outer side in the vehicle width direction of the rear floor panel 5 using attachment members 28 such as bolts, nuts, or rivets. As shown in the same figure, the support leg 32 on the outer side in the vehicle width direction is also fixed to the rear side frame upper 21 using attachment members 29 such as bolts, nuts, or rivets.

[0055] As shown in FIG. 4, the non-contact portion β2 of the energy absorbing member 30 is formed so as to be longer toward the front of the vehicle than the compressive deformation region α of the upper rear side frame 21 and the lower rear side frame 22.

[0056] In this way, the rear portion of the energy absorbing member 30 has a non-contact portion β2 that is not fixed to the vehicle body, thereby improving the amount of energy absorption without the energy absorbing member 30 interfering with the axial compression of the rear side frame upper 21 and the rear side frame lower 22 in the event of a rear-end collision. The above-mentioned mounting members 28, 29 are provided in plurality at predetermined intervals in the longitudinal direction of the vehicle, and the fixed portion β1 is supported at both ends by a pair of inner and outer support legs 31, 32.

[0057] As shown in FIG. 5, the lower surface of the non-contact portion β2 of the energy absorbing member 30 is located above the upper surface of the rear side frame upper 21 with a distance ΔL therebetween. As a result, the lower surface of the non-contact portion β2 is raised above the upper surface of the rear side frame upper 21, and when the rear portions of the rear side frame upper 21 and the rear side frame lower 22 are axially compressed during a rear-end collision of the vehicle, even if the rear portions of the rear side frame upper 21 and the rear side frame lower 22 deform like bellows, the energy absorbing member 30 does not hinder this deformation, thereby improving the amount of energy absorption.

[0058] As shown in FIGS. 4 and 7, rear end portions 31a and 32a of the fixing portion β1 of the energy absorbing member 30 are located further forward of the rear end portion 17a of the rear wheel house 17 in the vehicle. As a result, behind the rear wheel house 17 capable of axial compression of the rear side frame upper 21 and the rear side frame lower 22, by not providing the above-described fixing portion β1, it is configured to achieve both axial compression of the energy absorption member 30 and axial compression of the rear side frame upper 21 and the rear side frame lower 22. That is, by ensuring axial compression of these respective elements 30, 21, 22, improvement of the energy absorption amount is intended. [[ID=​​​​​​​​​​​​​​​​​In this way, by making the front side of the energy absorbing member 30 of the vehicle highly rigid, the energy absorbing member 30 is supported, and thereby, in the event of a rear collision, the energy absorbing member 30 is configured to stably undergo axial compressive deformation from its rear end.

[0063] 9 and 10, the energy absorbing member 30 has a rectangular cross section when viewed from the front of the vehicle. That is, the energy absorbing member 30 has a rectangular cross section in which an upper wall 33, a lower wall 34, and inner and outer side walls 35, 36 are connected in a substantially square frame shape when viewed from the front of the vehicle.

[0064] 9 and 10, the rectangular cross section of the energy absorbing member 30 is provided with vertical ribs 37 and horizontal ribs 38. The ribs 37 and 38 are configured to further improve the amount of energy absorbed by the energy absorbing member 30.

[0065] The number of the longitudinal ribs 37 and the transverse ribs 38 may be plural. Furthermore, instead of the longitudinal ribs 37 and the transverse ribs 38, a structure may be adopted in which inclined ribs are formed by combining ribs diagonally connecting the corners of a square shape in an X-shape when viewed from the front of the vehicle.

[0066] 11, notches 39 are provided at the rear end of the energy absorbing member 30 by cutting out ridge lines x1, x2, x3, and x4 of the quadrangular shape. In this embodiment, of the ridge lines x1 to x4 of the quadrangular shape, the upper two ridge lines x1 and x2 and the lower two ridge lines x3 and x4 in a front view of the vehicle, i.e., all of the ridge lines x1 to x4, are cut out to form the notches 39.

[0067] The length of the above-mentioned cutout portion 39 in the vehicle longitudinal direction is set to approximately 10 to 12% of the length of the area 30A located at the rearmost part of the energy absorbing member 30 in the vehicle longitudinal direction, but is not limited to this value.

[0068] In this way, by providing the notched portions 39 by cutting out the ridge lines x1 to x4, stress is concentrated at the notched portions 39 during a rear-end collision of the vehicle, which serves as a trigger for compressive deformation, and the energy absorbing member 30 is configured to be compressively deformed from its rear end portion more stably during a rear-end collision.

[0069] As shown in Figures 2 and 5, the upper surfaces of the pair of left and right energy absorbing members 30, 30, i.e., the upper surfaces of the upper walls 33, are configured to be located at the same height on the left and right when the energy absorbing members 30 are assembled to the vehicle, and the upper surfaces of the energy absorbing members 30 are located at a position higher than the upper surface of the spare tire 8 provided in the sub-trunk 7 below the trunk board 40, which is a luggage compartment member.

[0070] As a result, the pair of left and right energy absorbing members 30 function as trunk board support members, and are configured to reliably exhibit the support performance of the trunk board 40, which is a luggage compartment member.

[0071] 5 and 8, the rear end panel 9 is located behind the upper rear side frame 21 and the lower rear side frame 22. The rear end panel 9 and the rear end member 10 are provided with a position restricting member 50 that restricts the movement of the rear end of the energy absorbing member 30 in the vertical direction and the vehicle width direction.

[0072] The position restricting member 50 restricts the movement of the rear end of the energy absorbing member 30 in the vertical and transverse directions of the vehicle, thereby suppressing bending of the energy absorbing member 30 in the event of a rear-end collision of the vehicle and promoting axial compression of the energy absorbing member 30. In other words, if bending occurs in the energy absorbing member 30, the axial compression of the energy absorbing member 30 is hindered and the amount of energy absorption decreases, so the position restricting member 50 suppresses bending of the energy absorbing member 30.

[0073] As shown in Figures 5 and 8, the position regulating member 50 is made of a sheet metal member, and has an inverted, approximately U-shaped configuration with an opening 51 that opens downward, through which the rear end of the above-mentioned energy absorbing member 30 is inserted.

[0074] As shown in Figure 8, the position regulating member 50 comprises a member main body 52 having an approximately inverted U-shape, a joining flange portion 53 integrally formed on the inner side of the member main body 52 in the vehicle width direction, and a joining flange portion 54 integrally formed on the outer side of the member main body 52 in the vehicle width direction.

[0075] The above-mentioned opening 51 is formed at the bottom of the member body 52 so as to be open downward, and a recess 55 is provided continuous with this opening 51 and protruding toward the rear of the vehicle, and the rear end of the energy absorbing member 30 is inserted into the above-mentioned recess 55 through the above-mentioned opening 51.

[0076] 8, the upper portion of the member body 52 is fixed by welding to the front wall 10b of the rear end member 10 at a plurality of spot welds SW1 spaced apart in the vehicle width direction. In addition, each of the joining flange portions 53, 54 has a shape that follows the shape of a corresponding portion of the rear end panel 9.

[0077] The joining flange portion 53 on the inner side in the vehicle width direction is welded and fixed to the rear end panel 9 at a plurality of spot welds SW2 spaced apart in the vertical direction, as shown in Fig. 8. Similarly, the joining flange portion 54 on the outer side in the vehicle width direction is welded and fixed to the rear end panel 9 at a plurality of spot welds SW3 spaced apart in the vertical direction, as shown in Fig. 8.

[0078] In this way, the position control member 50 has an inverted, approximately U-shaped configuration with an opening 51 that opens downward, and by inserting the rear end of the energy absorbing member 30 into the opening 51, it is possible to achieve the effect of suppressing the bending of the energy absorbing member 30 and the effect of promoting axial compression of the energy absorbing member 30 with the addition of a simple structure.

[0079] The above-mentioned position regulating member 50 is a sheet metal member, and this position regulating member 50 may be fixed to the vehicle body by spot welding (see spot welding points SW1, SW2, SW3) to directly or indirectly connect the rear end member 10 and the rear side frame upper 21.

[0080] Figure 12 is a schematic side view showing the state of the vehicle before a rear-end collision load is input, Figure 13 is a schematic side view showing the state of the vehicle during a rear-end collision when the vehicle is equipped with an energy absorbing member 30 but does not have a position regulating member 50, and Figure 14 is a schematic side view showing the state of the vehicle during a rear-end collision when the vehicle is equipped with both an energy absorbing member 30 and a position regulating member 50.

[0081] FIG. 15 is a characteristic diagram showing the change in load (reaction force generated in the energy absorbing member 30) with respect to the time elapsed since the rear-end collision, with the horizontal axis representing the elapsed time and the vertical axis representing the load.

[0082] In Fig. 15, characteristic ALT1 is the characteristic at the time of a rear collision of the vehicle shown in Fig. 13 which is provided with the energy absorbing member 30 but does not have the position restricting member 50, and characteristic ALT2 is the characteristic at the time of a rear collision of the vehicle shown in Fig. 14 which is provided with both the energy absorbing member 30 and the position restricting member 50. However, each of the characteristics ALT1 and ALT2 in Fig. 15 is the characteristic when both the energy absorbing members 30 are made of PC (polycarbonate).

[0083] 12, 13, and 14, reference numeral 60 denotes a barrier used in vehicle collision tests, 61 denotes a protruding portion of the barrier 60 that corresponds to a front bumper reinforcement, 62 denotes a trailing arm of a rear suspension device, 63 denotes a torsion beam, and 64 denotes a tail pipe.

[0084] As shown in Figure 12, the rear side frame upper 21 and the rear side frame lower 22 face the protruding portion 61 of the barrier 60, while the energy absorbing member 30 does not face the protruding portion 61 of the barrier 60 and is positioned offset above the vehicle from the protruding portion 61.

[0085] Therefore, if the position regulating member 50 is not present, when the barrier 60 comes into contact with the rear end panel 9 via the rear bumper during a rear-end collision of the vehicle, the rear end of the energy absorbing member 30 slides upward as shown in Figure 13 and buckles, resulting in a decrease in the load from time t1 to t2 in the characteristic ALT1 of Figure 15.

[0086] On the other hand, if the position restricting member 50 is present, when the barrier 60 comes into contact with the rear end panel 9 via the rear bumper during a rear-end collision of the vehicle, the rear end of the energy absorbing member 30 is restricted from sliding upward and in the vehicle width direction by the position restricting member 50, and the energy absorbing member 30 is subjected to axial compression. Therefore, as shown from time t2 to t3 in the characteristic ALT2 in Figure 15, the load becomes substantially flat from the early stage of the collision, and energy can be appropriately absorbed.

[0087] In the figure, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow IN indicates the inside in the vehicle width direction, arrow OUT indicates the outside in the vehicle width direction, and arrow UP indicates the top of the vehicle.

[0088] As described above, the rear structure of a vehicle according to this embodiment comprises a pair of left and right rear frames (see the upper rear side frame 21 and the lower rear side frame 22) that extend in the longitudinal direction of the vehicle and have at their rear ends a compressive deformation region α that undergoes compressive deformation when subjected to a longitudinal collision load, a floor panel (rear floor panel 5) that is located between the pair of left and right rear frames (upper rear side frame 21, lower rear side frame 22) in the vehicle width direction, and a pair of left and right energy absorbing members 30 that extend in the longitudinal direction and undergo compressive deformation when subjected to a longitudinal collision load, and the energy absorbing members 30 are provided on the upper part of the rear frames (upper rear side frame 21) and in at least the compressive deformation region α (see Figures 2 to 4).

[0089] According to this type of vehicle rear structure, the energy absorption member 30 is provided on the upper part of the rear frame (rear side frame upper 21) and at least in the compressive deformation region α, so that when the rear frame (rear side frame upper 21, rear side frame lower 22) receives a longitudinal collision load at its rear end during a rear collision, the compressive deformation behavior of the rear frame (rear side frame upper 21, rear side frame lower 22) can be maintained.

[0090] Furthermore, since the energy absorbing member 30 is provided on the upper part of the rear frame (rear side frame upper 21) and in the compressive deformation region α, the energy absorbing member 30 can undergo compressive deformation without adversely affecting the deformation behavior of the rear frame (rear side frame upper 21, rear side frame lower 22), thereby improving the amount of energy absorption. In short, according to this embodiment, it is possible to improve the amount of collision energy absorbed in the event of a rear-end collision without increasing the cost or mass.

[0091] In addition, in such a rear structure of a vehicle, the energy absorbing member 30 supports a luggage compartment member (trunk board 40) that forms the lower surface of the luggage compartment 27 (see FIG. 4). According to such a vehicle rear structure, the energy absorbing member 30 supports the luggage compartment member (trunk board 40), so that it is possible to improve the amount of energy absorption while eliminating the support member conventionally provided in the sub-trunk.

[0092] Furthermore, in such a vehicle rear structure, the energy absorbing member 30 has a fixed portion β1 at the front that is fixed to the vehicle body, and a non-contact portion β2 at the rear that is not fixed to the vehicle body (see Figures 7, 9, and 10).

[0093] According to this type of rear structure of the vehicle, the rear of the energy absorbing member 30 has a non-contact portion β2 that is not fixed to the vehicle body, so that the energy absorbing member 30 does not hinder the axial compression of the rear frame (rear side frame upper 21, rear side frame lower 22) in the event of a rear-end collision of the vehicle, and the amount of energy absorbed by the energy absorbing member 30 can be improved.

[0094] Furthermore, in such a vehicle rear structure, the lower surface of the non-contact portion β2 is located above the upper surface of the rear frame (rear side frame upper 21) with a distance ΔL therebetween (see FIG. 5).

[0095] According to this type of rear structure of the vehicle, the lower surface of the non-contact portion β2 is floating above the upper surface of the rear frame (rear side frame upper 21). Therefore, when the rear portion of the rear frame (rear side frame upper 21, rear side frame lower 22) is axially compressed during a rear collision of the vehicle, even if the rear portion of the rear frame is deformed like a bellows, this is not hindered by the energy absorbing member 30, and the amount of energy absorption can be improved.

[0096] Additionally, in this vehicle rear structure, the rear ends 31a, 32a of the fixing portion β1 are located further forward of the rear end 17a of the rear wheel house 17 (see FIGS. 4 and 7). According to this type of rear structure of the vehicle, the fixing portion β1 is not provided behind the rear wheel house 17, where axial compression of the rear frame (rear side frame upper 21, rear side frame lower 22) is possible, thereby making it possible to achieve both axial compression of the energy absorbing member 30 and axial compression of the rear frame (rear side frame upper 21, rear side frame lower 22).

[0097] In addition, in such a vehicle rear structure, the energy absorbing member 30 is configured so that the rigidity increases toward the front of the vehicle at least in the compressive deformation region α (see FIG. 4). According to such a vehicle rear structure, the energy absorbing member 30 is supported by making the front side of the vehicle of the energy absorbing member 30 highly rigid, and thereby the energy absorbing member 30 can be stably subjected to axial compressive deformation from its rear end in the event of a rear collision.

[0098] Furthermore, in such a vehicle rear structure, the energy absorbing member 30 has longitudinal ribs 37 and lateral ribs 38 in its cross section (see FIGS. 9 to 11). According to such a vehicle rear structure, the ribs 37, 38 described above can further improve the amount of energy absorbed by the energy absorbing member 30.

[0099] Furthermore, in the rear structure of such a vehicle, a rear end panel 9 is provided at the rear of the rear frame (rear side frame upper 21, rear side frame lower 22), and a position restriction member 50 is provided on the rear end panel 9 to restrict movement of the rear end of the energy absorbing member 30 in the vertical and transverse directions of the vehicle (see Figures 5 and 8).

[0100] According to such a rear structure of a vehicle, the position regulating member 50 regulates the movement of the rear end of the energy absorbing member 30 in the vertical and transverse directions of the vehicle, thereby suppressing bending of the energy absorbing member 30 and promoting axial compression of the energy absorbing member 30.

[0101] Additionally, in such a vehicle rear structure, the position regulating member 50 has an inverted, approximately U-shaped configuration with an opening 51 that opens downward, and the rear end of the energy absorbing member 30 is inserted into the opening 51 (see Figures 5 and 8). According to such a vehicle rear structure, the effect of suppressing the breakage of the energy absorbing member 30 and the effect of promoting axial compression of the energy absorbing member 30 can be achieved by adding a simple structure.

[0102] In addition, in such a vehicle rear structure, the energy absorbing member 30 has a rectangular cross section, and a notch 39 is provided at the rear end of the energy absorbing member 30 by cutting out ridge lines x1 to x4 of the rectangular shape (see FIGS. 8 and 11).

[0103] According to such a vehicle rear structure, by providing the cutout portions 39 by cutting out the ridge lines x1 to x4, stress is concentrated at the cutout portions 39, which act as triggers for compressive deformation, so that the energy absorbing member 30 can be compressed and deformed from its rear end portion more stably in the event of a rear-end collision.

[0104] Furthermore, in such a vehicle rear structure, the upper surfaces of the pair of left and right energy absorbing members 30 are configured to be at the same height on the left and right when assembled to the vehicle, and the upper surfaces of the energy absorbing members 30 are located at a position higher than the upper surface of the spare tire 8 provided in the sub-trunk 7 below the luggage compartment member (trunk board 40) (see Figure 5).

[0105] According to such a vehicle rear structure, the pair of left and right energy absorbing members 30 function as support members for the trunk board 40, and can reliably provide support performance for the luggage compartment member (trunk board 40).

[0106] In the configuration of this invention and the correspondence with the above-mentioned embodiment, The floor panel of the present invention corresponds to the rear floor panel 5 of the embodiment, Similarly, The rear frame corresponds to the rear side frame upper 21 and rear side frame lower 22. The rear end of the fixed portion β1 corresponds to the rear ends 31a and 32a. The luggage compartment member corresponds to the trunk board 40, The present invention is not limited to the configurations of the above-described embodiments.

[0107] For example, in the above embodiment, the energy absorbing member 30 is divided into a plurality of areas 30A to 30E in the longitudinal direction of the vehicle, and the thickness of each section is successively increased from the rear of the vehicle to the front of the vehicle. However, instead of this structure, a structure having a tapered cross-sectional shape in which the thickness of the energy absorbing member 30 gradually increases without any steps from the rear end to the front end of the vehicle may be adopted.

[0108] Furthermore, the resin material forming the energy absorbing member 30 may be other synthetic resins that are useful for absorbing energy, instead of PP (polypropylene) or PC (polycarbonate).

[0109] Furthermore, instead of the approximately square frame shape shown in the embodiment, the cross-sectional shape of the energy absorbing member 30 may be a rectangular frame shape in which the height in the vertical direction is longer than the width in the vehicle width direction, or a rectangular frame shape in which the width in the vehicle width direction is longer than the height in the vertical direction. [Industrial Applicability]

[0110] As described above, the present invention is useful for a rear structure of a vehicle that includes a pair of left and right rear frames that extend in the fore-and-aft direction of the vehicle and receive a rear collision load, and a floor panel located between these left and right rear frames in the vehicle width direction. [Explanation of symbols]

[0111] 5...Rear floor panel (floor panel) 7...Subtrunk 8...Spare tire 9...Rear end panel 17...Rear wheelhouse 17a...Rear end 21...Rear side frame upper (rear frame) 22...Rear side frame lower (rear frame) 27...Luggage compartment 30...Energy absorbing member 31a, 32a...rear end portion (rear end portion of fixed portion) 37...Vertical rib 38...Horizontal rib 39...Notch 40... Trunk board (luggage compartment component) 50... Position control member 51...Opening α: Compression deformation region β1…Fixed part β2…Non-contact part x1~x4...ridge line

Claims

1. a pair of left and right rear frames extending in a vehicle longitudinal direction and having compressive deformation regions at rear ends thereof that are compressively deformed when subjected to a longitudinal collision load; a floor panel located between the pair of left and right rear frames in the vehicle width direction; a pair of left and right energy absorbing members extending in the front-rear direction and compressively deforming when subjected to a collision load in the front-rear direction; the energy absorbing member is provided on an upper portion of the rear frame and in at least the compressive deformation region, the energy absorbing member has a fixed portion at a front part thereof which is fixed to the vehicle body, and a non-contact portion at a rear part thereof which is not fixed to the vehicle body, The lower surface of the non-contact portion is located above and spaced apart from the upper surface of the rear frame. Rear structure of the vehicle.

2. The energy absorbing member supports a luggage compartment member that forms the lower surface of the luggage compartment. The rear structure of a vehicle according to claim 1.

3. The upper surfaces of the pair of left and right energy absorbing members are configured to be at the same height on the left and right when assembled to the vehicle, and the upper surfaces of the energy absorbing members are positioned higher than the upper surface of a spare tire provided in a sub-trunk below the luggage compartment member. The rear structure of a vehicle according to claim 2.

4. The rear end of the fixing portion is located forward of the rear end of the rear wheel house. The rear structure of a vehicle according to any one of claims 1 to 3.

5. The energy absorbing member is configured so that the rigidity increases toward the front of the vehicle at least in the compressive deformation region. The rear structure of a vehicle according to any one of claims 1 to 4.

6. The energy absorbing member has longitudinal and transverse ribs in its cross section. The rear structure of a vehicle according to any one of claims 1 to 5.

7. A rear end panel is provided at the rear of the rear frame, The rear end panel is provided with a position restricting member that restricts the movement of the rear end of the energy absorbing member in the vertical direction and the vehicle width direction. The rear structure of a vehicle according to any one of claims 1 to 6.

8. The position restriction member has a generally inverted U-shape with an opening that opens downward, and the rear end of the energy absorbing member is inserted into the opening. The rear structure of a vehicle according to claim 7.

9. The energy absorbing member has a rectangular cross section, and a notch is provided at the rear end of the energy absorbing member to cut out the ridge of the rectangular shape. The rear structure of a vehicle according to any one of claims 1 to 8.

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