Vehicle rear structure

Abstract

The objective is to obtain a vehicle rear structure that can suppress the deformation of a skeletal member formed integrally by casting during a rear-end collision of a vehicle whose rear body is composed of such a member. [Solution] A rear vehicle structure 10 comprises a frame member 20 integrally formed by casting and constituting the rear of the vehicle body, a side member 40 extending in the longitudinal direction of the vehicle and attached to the rear of the frame member 20, and a floor member 32 provided on the upper side of the side member 40 and having an elongated hole portion 38 with the longitudinal direction of the vehicle as its longitudinal direction, wherein the floor member 32 is fastened to the side member 40 by fasteners 18 inserted through the rearward portion of the elongated hole portion 38.

Description

Technical Field

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

Background Art

[0002] A vehicle having a skeletal member integrally formed by casting and constituting the rear part of the vehicle has been conventionally known (see, for example, Patent Document 1). A side member for supporting a rear bumper reinforcement is attached to this skeletal member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a floor member is provided on the skeletal member constituting the rear part of the vehicle and the side member is fixed to the floor member so as not to be movable toward the front side of the vehicle, when the vehicle is rear-ended, especially during a minor collision, a load is transmitted from the side member to the floor member and from the floor member to the skeletal member, so there is a risk that the skeletal member will deform.

[0005] Therefore, an object of the present invention is to obtain a rear structure of a vehicle that can suppress deformation of the skeletal member when the vehicle having a rear part of the vehicle body constituted by a skeletal member integrally formed by casting is rear-ended.

Means for Solving the Problems

[0006] To achieve the above objective, the vehicle rear structure according to the first embodiment of the present invention comprises a skeletal member integrally formed by casting and constituting the rear of the vehicle body; a side member extending in the longitudinal direction of the vehicle and attached to the rear of the skeletal member; and a floor member provided on the upper side of the side member and having an elongated hole whose longitudinal direction is in the longitudinal direction of the vehicle, wherein the floor member is fastened to the side member by fasteners inserted through the rearward portion of the elongated hole.

[0007] According to the first embodiment of the invention, a side member extending in the longitudinal direction of the vehicle is attached to the rear of a skeletal member that is integrally molded by casting to form the rear of the vehicle body. A floor member is provided on the upper side of the side member, and an elongated hole is formed in the floor member with the longitudinal direction of the vehicle as its longitudinal direction. The floor member is fastened to the side member by a fastener inserted through the rearward portion of the elongated hole.

[0008] Therefore, when a load is applied to the side member during a rear-end collision, the side member can move forward along the elongated hole. This reduces the load applied from the side member to the floor member, and reduces the load applied from the floor member to the frame member. In other words, deformation of the frame member is suppressed during a rear-end collision. It should be noted that "rear-end collision" here naturally includes minor collisions.

[0009] Furthermore, a second embodiment of the vehicle rear structure according to the present invention is the vehicle rear structure according to the first embodiment, wherein the floor member has a hole on the vehicle front side of the elongated hole and is fastened to the side member by a fastener inserted through the hole.

[0010] According to the second embodiment of the invention, the floor member has a hole on the vehicle front side of the elongated hole, and is fastened to the side member by a fastener inserted through the hole. Therefore, when a load greater than a predetermined value is applied during a rear collision of the vehicle, the load can be transmitted from the side member to the floor member, and from the floor member to the frame member. In other words, the frame member can absorb the energy of the load. Furthermore, even when a load is applied from below the vehicle, such as when the vehicle is driving on rough roads, the rigidity of the floor member against that load is ensured. As a result, the relative displacement of the floor member with respect to the frame member is suppressed.

[0011] Furthermore, the vehicle rear structure according to the third embodiment of the present invention is the vehicle rear structure according to the second embodiment, wherein the elongated hole and the hole are formed at positions along the longitudinal direction of the vehicle.

[0012] According to the third embodiment of the invention, the elongated hole and the hole are formed in a position aligned with the longitudinal direction of the vehicle. Therefore, compared to the case where the elongated hole and the hole are formed offset in the vehicle width direction from a position aligned with the longitudinal direction of the vehicle, the load can be efficiently transmitted from the side member to the floor member and from the floor member to the frame member during a rear collision of the vehicle.

[0013] Furthermore, the vehicle rear structure according to the fourth embodiment of the present invention is the vehicle rear structure according to the third embodiment, wherein the holes are formed in a plurality in the longitudinal direction of the vehicle.

[0014] According to the fourth embodiment of the invention, a plurality of holes are formed in the longitudinal direction of the vehicle. Therefore, compared to the case where only one hole is formed, the rigidity of the floor member against loads input from below the vehicle is effectively ensured, and the relative displacement of the floor member with respect to the frame member is effectively suppressed.

[0015] Furthermore, a fifth aspect of the vehicle rear structure according to the present invention is a vehicle rear structure according to the third or fourth aspect, wherein the elongated holes and the holes are formed in at least two rows with a predetermined interval in the vehicle width direction.

[0016] According to the fifth embodiment of the invention, the elongated holes and holes are formed in at least two rows with a predetermined interval in the vehicle width direction. Therefore, compared to the case where only one row of elongated holes and holes is formed, when a load greater than a predetermined value is applied during a rear collision of the vehicle, the load can be efficiently transmitted from the side member to the floor member, and from the floor member to the frame member. In addition, the rigidity of the floor member against loads applied from below the vehicle is more effectively ensured, and the relative displacement of the floor member with respect to the frame member is more effectively suppressed.

[0017] Furthermore, a sixth aspect of the vehicle rear structure according to the present invention is a vehicle rear structure according to the fifth aspect, wherein the floor member has bead portions extending in the longitudinal direction of the vehicle between the elongated holes or between the holes.

[0018] According to the sixth embodiment of the invention, the floor member has bead portions extending in the longitudinal direction of the vehicle between the elongated holes or between the holes. Therefore, compared to a case in which no bead portions extending in the longitudinal direction of the vehicle are formed on the floor member, the rigidity of the floor member against loads input from below the vehicle is more effectively ensured, and the relative displacement of the floor member with respect to the frame member is more effectively suppressed.

[0019] Furthermore, the seventh embodiment of the vehicle rear structure according to the present invention is a vehicle rear structure according to any one of the first to sixth embodiments, wherein the side member is formed in a closed cross-sectional shape.

[0020] According to the seventh embodiment of the invention, the side member is formed in a closed cross-sectional shape. Therefore, compared to the case in which the side member is not formed in a closed cross-sectional shape, the rigidity of the side member against the load applied during a rear-end collision of a vehicle is improved, and the amount of energy absorbed is increased.

[0021] Furthermore, the eighth aspect of the vehicle rear structure according to the present invention is the vehicle rear structure according to the seventh aspect, wherein the side member has a partition within a closed cross-section.

[0022] According to the invention of the eighth aspect, the side member has a partition portion within the closed cross-section. Therefore, compared with the case where no partition portion is formed within the closed cross-section of the side member, the rigidity of the side member against the load input during a rear-end collision of the vehicle is further improved, and the energy absorption amount is further increased.

[0023] Moreover, the vehicle rear structure according to the ninth aspect of the present invention is the vehicle rear structure of the seventh or eighth aspect, in which a wall portion perpendicular to the vehicle front-rear direction and a flange portion protruding toward the rear side of the vehicle are formed at the rear portion of the skeletal member, and the side member is attached to the flange portion in a state of abutting against the wall portion.

[0024] According to the invention of the ninth aspect, a wall portion perpendicular to the vehicle front-rear direction and a flange portion protruding toward the rear side of the vehicle are formed at the rear portion of the skeletal member, and the side member is attached to the flange portion in a state of abutting against the wall portion. Therefore, the contact area of the side member with respect to the skeletal member is ensured, and the pressure on the skeletal member due to the load input to the side member during a rear-end collision of the vehicle is reduced. That is, the local input of the load to the skeletal member is suppressed, and the load is effectively received by the skeletal member. Here, the "perpendicular" includes a substantially perpendicular that is slightly deviated from the exact perpendicular.

[0025] Moreover, the vehicle rear structure according to the tenth aspect of the present invention is the vehicle rear structure of any one of the seventh to ninth aspects, in which the side members are provided in a pair on the left and right and support a bumper reinforcement extending in the vehicle width direction.

[0026] According to the invention of the tenth aspect, the side members are provided in a pair on the left and right and support a bumper reinforcement extending in the vehicle width direction. Therefore, the load input to the bumper reinforcement during a rear-end collision of the vehicle is efficiently dispersed and transmitted to the side members.

[0027] Moreover, the vehicle rear structure according to the 11th aspect of the invention is the vehicle rear structure according to any one of the 1st to 10th aspects, and the long hole portion is formed in a shape in which the width along the vehicle width direction decreases as it goes toward the vehicle front side.

[0028] According to the invention of the 11th aspect, the long hole portion is formed in a shape in which the width along the vehicle width direction decreases as it goes toward the vehicle front side. Therefore, due to the load input during a rear-end collision of the vehicle, the side member is appropriately guided toward the vehicle front side, and the load from the fastener is effectively transmitted toward the vehicle front side.

[0029] Moreover, the vehicle rear structure according to the 12th aspect of the invention is the vehicle rear structure according to any one of the 1st to 10th aspects, and the long hole portion is formed in an elliptical shape in which the width of the vehicle front side portion along the vehicle width direction is larger than that of the vehicle rear side portion.

[0030] According to the invention of the 12th aspect, the long hole portion is formed in an elliptical shape in which the width of the vehicle front side portion along the vehicle width direction is larger than that of the vehicle rear side portion. Therefore, due to the load input during a rear-end collision of the vehicle, the side member is appropriately guided toward the vehicle front side, and stress concentration from the fastener is reduced.

[0031] Moreover, the vehicle rear structure according to the 13th aspect of the invention is integrally formed by casting, and includes a skeletal member that constitutes the rear portion of the vehicle body, a side member that extends in the vehicle front-rear direction and is attached to the rear portion of the skeletal member, and a floor member that is provided above the vehicle side member and has a hole portion. The floor member is fastened to the side member by a fastener inserted through the hole portion, and a weak portion is formed at the edge end portion on the vehicle front side of the hole portion for breaking the floor member by the fastener when a load is input from the vehicle rear side.

[0032] According to the 13th embodiment of the invention, a side member extending in the longitudinal direction of the vehicle is attached to the rear of a skeletal member that is integrally molded by casting to form the rear of the vehicle body. A floor member is provided on the upper side of the side member, and a hole is formed in the floor member. The floor member is fastened to the side member by fasteners inserted through the hole, and a weak point is formed at the front edge of the hole on the vehicle side, which is designed to break the floor member when a load is applied from the rear of the vehicle by the fasteners.

[0033] Therefore, when a load is applied to the side member during a rear-end collision, the side member can move forward while fracturing its weak points at the fasteners. This reduces the load applied from the side member to the floor member, and from the floor member to the frame member. In other words, deformation of the frame member is suppressed during a rear-end collision. It should be noted that "rear-end collision" here naturally includes minor collisions. [Effects of the Invention]

[0034] As described above, according to the present invention, when a rear section of a vehicle body is composed of a skeletal member integrally formed by casting, deformation of the skeletal member can be suppressed during a rear-end collision. [Brief explanation of the drawing]

[0035] [Figure 1] This is a schematic perspective view showing the rear structure of the vehicle according to this embodiment, viewed from the rear and above. [Figure 2] This is a schematic perspective view showing the rear structure of the vehicle according to this embodiment, viewed from the front and above. [Figure 3] This is a schematic plan view showing the rear structure of the vehicle according to this embodiment. [Figure 4] This is a schematic exploded perspective view showing the rear structure of the vehicle according to this embodiment, viewed from the rear and below. [Figure 5] This is a schematic perspective view showing the rear structure of the vehicle according to this embodiment, viewed from the rear and below. [Figure 6]This is a schematic cross-sectional view of the rear side member constituting the vehicle rear structure according to this embodiment. [Figure 7] (A) A schematic plan view showing the shape of the elongated hole in the rear floor side panel constituting the rear structure of the vehicle according to this embodiment. (B) A schematic plan view showing a modified example of the elongated hole in the rear floor side panel constituting the rear structure of the vehicle according to this embodiment. [Figure 8] (A) A schematic plan view showing a weak point in the rear floor side panel constituting the rear structure of the vehicle according to this embodiment. (B) A schematic plan view showing a modified example of the weak point in the rear floor side panel constituting the rear structure of the vehicle according to this embodiment. [Modes for carrying out the invention]

[0036] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP will indicate the upward direction of the vehicle, the arrow FR will indicate the forward direction of the vehicle, and the arrow RH will indicate the right direction of the vehicle. Therefore, in the following description, when the directions of up and down, front and back, and left and right are described without further specification, they will refer to the up and down direction of the vehicle, the front and back direction of the vehicle, and the left and right direction of the vehicle (vehicle width direction).

[0037] As shown in Figure 1, the vehicle 12 equipped with the vehicle rear structure 10 according to this embodiment has a skeletal member (hereinafter referred to as "rear body 20") that constitutes the rear of the vehicle body. The rear body 20 as a skeletal member is a casting called a Gigacast, in which multiple parts are integrally formed by casting a metal such as aluminum alloy.

[0038] At the outer ends in the vehicle width direction of the rear section 20 of the vehicle body, symmetrical wheelhouses 22 capable of accommodating the left and right rear wheels are integrally formed. Side member outer panels 14, which constitute the outer body of the vehicle 12, are disposed on the outer side in the vehicle width direction of each wheelhouse 22. Between the wheelhouses 22 of the rear section 20 of the vehicle body, a floor section 24, which constitutes the bottom wall of the cargo compartment, is integrally formed.

[0039] As shown in Figures 1 to 3, a rear floor panel 30 is provided in the center of the vehicle width direction, rearward from the floor section 24, and together with the floor section 24, it forms the bottom wall of the cargo area. Furthermore, rear floor side panels 32 are provided on both the left and right sides of the rear floor panel 30, also serving as floor members that, together with the floor section 24 and the rear floor panel 30, form the bottom wall of the cargo area. This configuration allows for a large cargo space to be secured.

[0040] The rear floor side panel 32 has multiple upward-convex beads 34 extending in the front-rear direction, spaced apart in the vehicle width direction. On both the left and right sides of each upward-convex bead 34, multiple circular holes 36 (see Figure 2) for fastening are formed along the front-rear direction. In other words, the rear floor side panel 32 has upward-convex beads 34 extending in the front-rear direction, spaced between multiple holes 36 aligned in the vehicle width direction.

[0041] Here, in the rear floor side panel 32, the holes on both the left and right sides of the upper convex bead 34, which is formed on the innermost side in the vehicle width direction, and at the rear end, are each elongated holes 38 with the front-rear direction as their longitudinal direction. As shown in Figure 7(A), each elongated hole 38 is formed in a roughly teardrop shape, with the width along the vehicle width direction gradually decreasing as it moves towards the front in a plan view, and the inner diameter at the rear end is approximately the same as the outer diameter of the shaft portion 18A of the bolt 18 used as a fastener.

[0042] The shape of the elongated hole 38 is not limited to the shape shown in Figure 7(A). For example, as shown in Figure 7(B), it may be formed in a substantially elliptical shape where the front portion is wider in the vehicle width direction than the rear portion when viewed from above. However, it is preferable that the maximum inner diameter R1 of the front portion of the elongated hole 38 shown in Figure 7(B) in the vehicle width direction is smaller than the outer diameter R2 of the shaft portion 18A of the bolt 18.

[0043] Although not shown in the illustration, the elongated hole portion 38 may also be formed in a substantially rectangular shape in plan view. In any case, as shown in Figure 3, the elongated hole portion 38 and the hole portion 36 are formed in positions along the front-rear direction, and two elongated hole portions 38 are formed with the upper convex bead 34 in between. In other words, the elongated hole portion 38 and the hole portion 36 are formed in two rows with a predetermined interval in the vehicle width direction.

[0044] As shown in Figures 4 and 5, a rear side member 40 is provided on the lower side of the rear floor side panel 32 as a side member extending in the front-rear direction. Specifically, as shown in Figure 6, the rear side member 40 is formed in a substantially rectangular closed cross-sectional shape by extrusion molding of a metal such as an aluminum alloy, and a partition portion 42 is integrally formed within the closed cross-section, which is substantially "+" shaped when viewed from the front-rear direction (dividing the inside of the closed cross-section into four compartments).

[0045] Furthermore, as shown in Figure 4, a rear wall 26 is integrally formed on the lower rear end (rear) of the rear portion 20 of the vehicle body on the outer side in the vehicle width direction, and a pair of substantially rectangular flat flange portions 28 are integrally formed on both the left and right sides of the rear wall 26, extending a predetermined length toward the rear.

[0046] The vertical length of each flange portion 28 is approximately the same as the vertical length of the rear wall 26, and the spacing between the flange portions 28 (the width of the rear wall 26 along the vehicle width direction) is approximately the same as the width of the rear side member 40 along the vehicle width direction. Bolt insertion holes 28A are formed vertically in each flange portion 28.

[0047] Furthermore, the front end surface 40F of the rear side member 40 (see also Figure 2) is a plane that is substantially perpendicular to the front-rear direction, and the length of the rear side member 40 in the vertical direction is substantially the same as the length of the rear wall 26 of the rear part 20 of the vehicle body in the vertical direction. In addition, bolt insertion holes 40A are formed vertically at predetermined positions on both the left and right side walls 40S at the front end of the rear side member 40.

[0048] Therefore, the rear side member 40 is positioned so that its front end surface 40F abuts against the rear wall 26 of the rear part 20 of the vehicle body, and its left and right side walls 40S at its front end are in contact with each flange portion 28 from the inside. In this state, the front end of the rear side member 40 is attached to the rear part 20 of the vehicle body by inserting the bolts 18 through the holes 28A of each flange portion 28 and the holes 40A of the rear side member 40 and screwing them onto nuts (not shown).

[0049] Furthermore, the rear side member 40 is attached to the rear floor side panel 32, which is located above it, by bolting its upper wall 40U. Specifically, bolt insertion holes (not shown) are formed at multiple predetermined positions on the upper wall 40U of the rear side member 40.

[0050] Therefore, the rear floor side panel 32 is fastened to the rear of the upper wall 40U of the rear side member 40 by bolts 18 inserted through the rear end (rear side portion) of each elongated hole 38 and screwed into nuts (not shown), and fastened to the central and front portions of the upper wall 40U of the rear side member 40 by bolts 18 inserted through each hole 36 formed on the front side of each elongated hole 38 and screwed into nuts (not shown).

[0051] Furthermore, the rear side members 40 are provided in pairs, one on each side, and support plates 44 are welded to their rear end faces. The support plates 44 are sized to slightly protrude from the rear side members 40 when viewed from the front-rear direction. The outer end of the front wall of the rear bumper reinforcement 16, which has a closed cross-section shape extending in the vehicle width direction, is attached to the support plates 44 by bolting or the like.

[0052] In other words, the rear bumper reinforcement 16 is supported by a pair of left and right rear side members 40. Furthermore, a partition portion 17 (see Figure 1) is integrally formed in the vertical center of the rear bumper reinforcement 16, dividing the closed cross-section into two upper and lower compartments. This configuration ensures the rigidity of the rear bumper reinforcement 16 against loads applied from the rear.

[0053] The operation of the vehicle rear structure 10 according to this embodiment, which has the configuration described above, will now be explained.

[0054] As described above, the rear bumper reinforcement 16 is supported by a pair of left and right rear side members 40. Therefore, in the event of a rear collision of the vehicle 12 (including a minor collision), a load is applied to the rear bumper reinforcement 16, and the energy is absorbed by the rear bumper reinforcement 16. However, any load that the rear bumper reinforcement 16 cannot absorb is efficiently distributed and transmitted from the rear bumper reinforcement 16 to the pair of left and right rear side members 40.

[0055] Here, a rear wall 26 having a plane that is substantially perpendicular to the front-rear direction is formed at the lower rear end of the rear portion 20 on the outer side in the vehicle width direction, and a pair of left and right rear side members 40 are attached by bolting the left and right side walls 40S at the front end to the flange portions 28 that protrude from both the left and right sides of the rear wall 26 toward the rear, with their respective front end surfaces 40F in contact with the respective rear wall 26.

[0056] Therefore, the contact area of ​​the front end surface 40F of the rear side member 40 with the rear wall 26 of the rear of the vehicle body 20 is appropriately secured, and the pressure on the rear wall 26 of the rear of the vehicle body 20 due to the load applied to the rear side member 40 during a rear collision of the vehicle 12 can be reduced. In other words, the localized input of load to the rear wall 26 of the rear of the vehicle body 20 can be suppressed, and that load can be effectively absorbed by the rear wall 26 of the rear of the vehicle body 20.

[0057] In particular, since the rear side member 40 is formed in a closed cross-sectional shape, the rigidity of the rear side member 40 against the load applied during a rear collision of the vehicle 12 can be improved compared to when the rear side member 40 is not formed in a closed cross-sectional shape, and the amount of energy absorbed can be increased.

[0058] Furthermore, a partition portion 42, which is roughly "+" shaped when viewed from the front-rear direction, is integrally formed within the closed cross-section of the rear side member 40. Therefore, compared to a case where the partition portion 42 is not formed within the closed cross-section of the rear side member 40, the rigidity of the rear side member 40 against the load applied during a rear-end collision of the vehicle 12 can be further improved, and the amount of energy absorbed can be further increased.

[0059] Furthermore, the inner portion of the rear floor side panel 32 in the vehicle width direction is provided on the upper side of the rear side member 40, and an elongated hole 38 is formed at the rear end of the inner portion of the rear floor side panel 32 in the vehicle width direction, with the longitudinal direction being the front-rear direction. The inner portion of the rear floor side panel 32 in the vehicle width direction is fastened to the rear of the upper wall 40U of the rear side member 40 by a bolt 18 inserted through the rear end of the elongated hole 38.

[0060] Therefore, when a load is applied from the rear bumper reinforcement 16 to the rear side member 40 during a rear-end collision of the vehicle 12, at least the rear side of the rear side member 40 can move forward along the elongated hole 38 while undergoing compressive plastic deformation (while absorbing energy). This reduces the load applied from the rear side member 40 to the rear floor side panel 32, and reduces the load applied from the rear floor side panel 32 to the outer portion of the rear of the vehicle body 20, particularly the wheel well 22.

[0061] In other words, compared to the case where the rear of the upper wall 40U of the rear side member 40 is fixed to the rear floor side panel 32 by spot welding or the like so that it cannot move forward, plastic deformation of the rear floor side panel 32 can be suppressed, and plastic deformation of the rear of the vehicle body 20 can be suppressed. Therefore, repairs to a vehicle 12 that has been hit from behind may only require the replacement of, for example, the rear bumper reinforcement 16 and the rear side member 40, making it easy to handle.

[0062] Furthermore, as shown in Figure 7(A), the elongated hole 38 is formed in a shape where its width along the vehicle width direction gradually decreases as it moves towards the front. Therefore, the load applied during a rear collision of the vehicle 12 can appropriately guide at least the rear side of the rear side member 40 toward the front, and the load from the shaft portion 18A of the bolt 18 can be effectively transmitted toward the front.

[0063] Furthermore, as shown in Figure 7(B), the elongated hole 38 may be formed in an elliptical shape, with the front portion having a wider width in the vehicle width direction than the rear portion. In this case, the load applied during a rear collision of the vehicle 12 can appropriately guide at least the rear side of the rear side member 40 forward, and stress concentration on the rear floor side panel 32 due to the shaft portion 18A of the bolt 18 can be reduced.

[0064] Furthermore, the rear floor side panel 32 has a hole 36 on the front side of the elongated hole 38, and is fastened to the rear side member 40 by a bolt 18 inserted through the hole 36. Therefore, in the event of a rear collision of the vehicle 12, when a load greater than a predetermined value is applied from the rear bumper reinforcement 16 to the rear side member 40, that load can be efficiently transmitted from the rear side member 40 to the rear floor side panel 32, and then efficiently transmitted from the rear floor side panel 32 to the rear of the vehicle body 20.

[0065] In other words, in the event of a rear-end collision where a load exceeding a predetermined value is applied, the vehicle 12 can efficiently absorb energy not only through the plastic deformation of the rear side member 40, but also through the plastic deformation of the rear floor side panel 32 and the rear of the vehicle body 20. Thus, in this embodiment, the vehicle 12 can utilize not only the rear side member 40, but also the rear floor side panel 32 and the rear of the vehicle body 20 as energy-absorbing members.

[0066] Furthermore, even when the vehicle 12 is driving on rough roads with many bumps and uneven surfaces, or when a load is applied from below, the rigidity of the rear floor side panel 32 against that load can be ensured. Therefore, the relative displacement (deformation) of the less rigid rear floor side panel 32 relative to the more rigid rear body 20 can be suppressed, and the generation of high stress in the part of the rear floor side panel 32 fastened with bolts 18 can be suppressed.

[0067] Furthermore, since multiple holes 36 are formed in the front-rear direction, the rigidity of the rear floor side panel 32 against loads applied from below can be effectively ensured compared to the case where only one hole 36 is formed, and the relative displacement of the rear floor side panel 32 with respect to the rear of the vehicle body 20 can be effectively suppressed.

[0068] Furthermore, the elongated hole 38 and the hole 36 are formed in positions aligned with the front-rear direction. Therefore, compared to the case where the elongated hole 38 and the hole 36 are formed offset in the vehicle width direction from positions aligned with the front-rear direction, the load of the vehicle 12 can be transmitted more efficiently from the rear side member 40 to the rear floor side panel 32, and from the rear floor side panel 32 to the rear of the vehicle body 20 during a rear collision.

[0069] Furthermore, the elongated holes 38 and holes 36 are formed in two rows with the upper convex bead 34 in between (with a predetermined gap in the vehicle width direction). Therefore, compared to the case where only one row of elongated holes 38 and holes 36 is formed, even when a load greater than a predetermined value is input from the rear bumper reinforcement 16 to the rear side member 40 during a rear collision of the vehicle 12, the load can be transmitted more efficiently from the rear side member 40 to the rear floor side panel 32, and then more efficiently from the rear floor side panel 32 to the rear of the vehicle body 20.

[0070] Furthermore, since the elongated holes 38 and holes 36 are formed in two rows with the upper convex bead 34 in between (with a predetermined gap in the vehicle width direction), the rigidity of the rear floor side panel 32 against loads input from below can be more effectively ensured, and the relative displacement of the rear floor side panel 32 with respect to the rear of the vehicle body 20 can be more effectively suppressed.

[0071] In other words, since the rear floor side panel 32 has an upward-convex bead 34 extending in the longitudinal direction between the elongated holes 38 and between the holes 36, the rigidity of the rear floor side panel 32 against loads applied from below can be more effectively ensured compared to a rear floor side panel 32 in which an upward-convex bead 34 extending in the longitudinal direction is not formed, and the relative displacement of the rear floor side panel 32 with respect to the rear of the vehicle body 20 can be more effectively suppressed.

[0072] (modified version) As shown in Figure 8, instead of elongated holes 38, holes 36 may be formed at the rear ends on both the left and right sides of the upper convex bead 34 in the inner portion of the rear floor side panel 32 in the vehicle width direction. A weak portion 37 may also be formed at the front edge of the hole 36 to allow the shaft portion 18A of the bolt 18 to break the rear floor side panel 32 when a load is applied to the rear side member 40 from the rear.

[0073] The weak portion 37 is composed of a notch 37A that is approximately isosceles triangular in plan view and continuous with the hole 36, as shown in Figure 8(A), for example. However, the weak portion 37 is not limited to the notch 37A, and may also be composed of a cut 37B that extends in the front-rear direction for a predetermined length and width and is continuous with the hole 36, as shown in Figure 8(B), for example.

[0074] If such weak points 37 (notches 37A and notches 37B) are formed on both the left and right sides of the upper convex bead 34 on the inner side in the vehicle width direction of the rear floor side panel 32, and on the front edge of the hole 36 at the rear end, then when a load is applied to the rear side member 40 during a rear collision of the vehicle 12, at least the rear side of the rear side member 40 can move forward while undergoing compressive plastic deformation (absorbing energy) and while the weak points 37 are fractured by the shaft portion 18A of the bolt 18 fastened to the rear of the upper wall 40U.

[0075] As a result, in the event of a rear collision of the vehicle 12, the load input from the rear side member 40 to the rear floor side panel 32 can be reduced, thereby suppressing plastic deformation of the rear floor side panel 32. Furthermore, the load input from the rear floor side panel 32 to the rear of the vehicle body 20, particularly the outer portion in the vehicle width direction including the wheel well 22, can be reduced, thereby suppressing plastic deformation of the rear of the vehicle body 20.

[0076] The vehicle rear structure 10 according to this embodiment has been described above with reference to the drawings. However, the vehicle rear structure 10 according to this embodiment is not limited to the illustrated version, and can be modified as appropriate without departing from the spirit of the present invention. For example, the rear floor side panel 32 is not limited to being composed of a single panel, but may be composed of two overlapping panels.

[0077] Furthermore, depending on the width of the upper wall 40U of the rear side member 40 along the vehicle width direction and the width of the upper convex bead 34 along the vehicle width direction, there may be only one elongated hole 38 or three elongated holes 38 may be provided in the vehicle width direction. In other words, it is preferable that the elongated holes 38 and holes 36 for bolting the rear floor side panel 32 and the upper wall 40U of the rear side member 40 be formed in at least two rows with a predetermined interval in the vehicle width direction, but it is also acceptable for them to be formed in only one row.

[0078] Furthermore, the upward-convex bead 34 may not be formed between the elongated holes 38, but may be formed extending forward from between the holes 36 at the rearmost side. Also, the partition portion 42 is not limited to being formed in a substantially "+" shape when viewed from the front-rear direction. In addition, the flange portion 28 may protrude to the rear from both the upper and lower sides, rather than from both the left and right sides of the rear wall 26, or it may protrude to the rear from both the left and right sides and the lower side. [Explanation of Symbols]

[0079] 10. Rear structure of the vehicle 16. Rear bumper reinforcement (bumper reinforcement) 18 bolts (fasteners) 20. Rear of the vehicle body (framework components) 26 Rear wall (wall part) 32. Rear floor side panel (floor component) 34. Convex bead (bead portion) 36 Hole 37 Vulnerable parts 38 Long hole part 40 Rear side member (side member) 42 Partition section

Claims

1. The structural members that form the rear of the vehicle body are integrally molded by casting, A side member extending in the longitudinal direction of the vehicle and attached to the rear of the frame member, A floor member provided on the upper side of the vehicle of the aforementioned side member, having an elongated hole with the vehicle's longitudinal direction as its longitudinal direction, Equipped with, The aforementioned floor member is A rear vehicle structure fastened to the side member by a fastener inserted through the rear portion of the elongated hole.

2. The aforementioned floor member is The rear vehicle structure according to claim 1, wherein the elongated hole portion has a hole on the front side of the vehicle and is fastened to the side member by a fastener inserted through the hole.

3. The vehicle rear structure according to claim 2, wherein the elongated hole and the hole are formed in a position along the front-rear direction of the vehicle.

4. The vehicle rear structure according to claim 3, wherein the aforementioned holes are formed in multiple locations in the front-rear direction of the vehicle.

5. The vehicle rear structure according to claim 4, wherein the elongated holes and the holes are formed in at least two rows spaced apart in the vehicle width direction.

6. The rear vehicle structure according to claim 5, wherein the floor member has bead portions extending in the vehicle longitudinal direction between the elongated holes or between the holes.

7. The vehicle rear structure according to any one of claims 1 to 6, wherein the side member is formed in a closed cross-sectional shape.

8. The vehicle rear structure according to claim 7, wherein the side member has a partition within a closed cross-section.

9. The rear of the aforementioned skeletal member is formed with a wall portion perpendicular to the vehicle's longitudinal direction and a flange portion that protrudes toward the rear of the vehicle. The rear vehicle structure according to claim 7, wherein the side member is attached to the flange portion in a state in contact with the wall portion.

10. The vehicle rear structure according to claim 7, wherein the side members are provided in pairs on the left and right sides and support bumper reinforcements extending in the vehicle width direction.

11. The vehicle rear structure according to any one of claims 1 to 6, wherein the elongated hole is formed in a shape in which the width along the vehicle width direction decreases as it moves toward the front of the vehicle.

12. The vehicle rear structure according to any one of claims 1 to 6, wherein the elongated hole is formed in an elliptical shape such that the front portion of the vehicle is wider in the vehicle width direction than the rear portion of the vehicle.

13. The structural members that form the rear of the vehicle body are integrally molded by casting, A side member extending in the longitudinal direction of the vehicle and attached to the rear of the frame member, A floor member having a hole is provided on the upper side of the vehicle of the aforementioned side member, Equipped with, The aforementioned floor member is The side member is fastened by a fastener inserted through the aforementioned hole, A rear vehicle structure in which a weak point is formed at the front edge of the hole on the vehicle side, so as to cause the floor member to break when a load is applied from the rear of the vehicle by the fastener.

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