JP2015096351A - Rear part vehicle body structure of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rear part vehicle body structure of an automobile which can protect a fuel tank without sacrificing capacity of the fuel tank, layout of the vehicle body bottom part, weight, and NVH performance.SOLUTION: In a rear part vehicle body structure of an automobile, rear end parts of right and left side members 22, 22 are respectively mounted on undersurfaces of rear side frames 7, and front end parts thereof are mounted on a frontside cross member part 23. The frontside cross member part 23 extended at the front side of the rear side frames 7 in a vehicle width direction at a position immediately after a fuel tank 14 comprises: a midship part 23C which is approximately linear-shaped in the vehicle width direction in a plain view of the vehicle; ramp parts 23S which are obliquely bended and extended from both end parts of the midship part 23C in the vehicle width direction to an outside front direction in the vehicle width direction. Both end parts of the ramp parts 23S in the vehicle width direction are mounted on the undersurfaces of the right and left rear side frames 7, 7.

Description

  The present invention relates to a rear vehicle body structure including a rear subframe having left and right side member portions and front and rear cross member portions.

  In general, a rear sub-frame (which agrees with a rear suspension cross member) that supports a suspension on the rear side has left and right side member portions, and front and rear cross member portions, and includes the rear sub-frame. As a rear body structure of an automobile, a structure shown in FIG. 14 is known.

  The conventional structure schematically shown in the bottom view in FIG. 14 (Patent Document 1) is provided with subframes 80 having left and right side member portions 81, 81 and front and rear cross member portions 82, 83. The vehicle body attachment portion 81a on the front side of the side member portions 81, 81 is connected to the vehicle body cross member 84, the vehicle body attachment portion 81b on the rear side is connected to the rear side frame 85, and both ends in the vehicle width direction of the front cross member portion 82 are connected to the left and right sides. It is connected to the member portions 81 and 81.

  In FIG. 14, a part of the above-mentioned side member portion 81 is bent in a substantially arc shape inward in the vehicle width direction in a vehicle plan view. In this bent structure, the spring of the lower arm of the rear wheel suspension is supported by the pedestal of the rear side frame 85, so that the space for arranging the spring is secured, the toe angle with respect to the vertical movement of the rear wheel 86 by increasing the arm length, etc. This is to achieve the purpose of suppressing the change in geometry.

Further, the above-mentioned side member portion 81 extends substantially in parallel to the vehicle front-rear center line in the vehicle width direction on the inner side in the vehicle width direction from the rear side frame 85, and the front end portion thereof is more forward of the vehicle than the front cross member portion 82. Protruding.
In FIG. 14, reference numeral 87 denotes a front lower arm, 88 denotes a rear lower arm, and in the drawing, arrow F indicates the front of the vehicle and arrow R indicates the rear of the vehicle.

The conventional structure shown in FIG. 14 has the following problems.
That is, a fuel tank is generally provided on the lower surface of the vehicle body. When the subframe 80 is provided immediately after the fuel tank 90 as shown in FIG. 13, it protrudes forward of the vehicle from the front cross member portion 82. It is necessary to separate the front end portion of the side member portion 81 from the rear portion of the fuel tank 90 so that the front end portion of the side member portion 81 is not in contact with the fuel tank 90 at the time of a rear collision. For this reason, there existed a problem that the capacity | capacitance of the fuel tank 90 became small and the layout of the vehicle body bottom part became redundant in the vehicle front-back direction.

Therefore, as in the subframe 100 shown in FIGS. 15A and 15B, the vehicle body mounting portions 82a and 82a at both ends of the front cross member portion 82 are connected to the rear side frame 85 and the left and right side member portions 81 are connected. , 81 may be connected to the front cross member 82.
15 (a) and 15 (b), the front cross member portion 82 is arranged in front of the vehicle as compared with the case of the subframe 80, and the center portion of the front cross member portion 82 is arranged in the vertical direction (FIG. 15 (a)). , (B), a bent portion 82b that is bent downward is formed, and a part of the fuel tank 90 protrudes in the space behind the vehicle formed by the bent portion 82b. Thus, the capacity of the fuel tank 90 can be ensured regardless of the front arrangement of the front cross member portion 82.

  However, in the subframe 100 shown in FIGS. 15A and 15B, the static rigidity of the subframe 100 is reduced by bending the center portion of the front cross member portion 82 in the vertical direction as described above. In order to compensate for this, there has been a problem that the weight is increased, and it is difficult to improve the NVH (Noise Vibration Harness) performance as the front cross member 82 is bent. In FIG. 15, the same parts as those in FIG. 14 are denoted by the same reference numerals.

JP 2013-95393 A

  Accordingly, an object of the present invention is to provide a rear vehicle body structure that can protect a fuel tank without sacrificing the capacity of the fuel tank, the layout, weight, and NVH performance of the bottom of the vehicle body.

  The rear vehicle body structure of the vehicle according to the present invention is a rear vehicle body structure including a rear subframe having left and right side member portions and front and rear cross member portions, wherein the left and right side member portions are A rear end portion is attached to the lower surface of the left and right rear side frames at the rear of the vehicle body, while a front end portion is attached to the front cross member portion, and from the attachment portion of the rear end portion to the rear of the rear wheel axle of the rear wheel suspension. A rear side member that extends forward inward in the vehicle width direction to the spring of the lower arm that is positioned; a bent portion that is bent toward the front of the vehicle on the inner side in the vehicle width direction of the spring; and the bent portion on the inner side in the vehicle width direction from the rear side frame A side member front center portion extending substantially parallel to the front-rear vehicle body center line and the vehicle plan view from the front end mounting portion to the front end portion, The side cross member portion extends in the vehicle width direction at a position immediately after the fuel tank disposed on the lower surface of the vehicle body at the front portion of the rear side frame, and is substantially linear in the vehicle width direction in a plan view of the vehicle. A central portion and inclined portions extending obliquely from the both ends of the central portion in the vehicle width direction to the front in the vehicle width direction, and the both ends of the inclined portions in the vehicle width direction of the left and right rear side frames. It is attached to the lower surface.

According to the above configuration, since the front end portions of the left and right side member portions are attached to the front cross member portion, it is possible to ensure a sufficient distance between the front end portions of the left and right side member portions and the fuel tank.
Further, at the time of a rear collision, a rear collision load is input to the rear sub-frame, but the front cross member portion has a center portion that is substantially straight in the vehicle width direction in a plan view of the vehicle and both ends of the center portion in the vehicle width direction. Since it has a substantially arch shape in a vehicle plan view with an inclined portion that is bent and extended obliquely forward and outward in the vehicle width direction, the rear impact load can be firmly received by the inclined portion constituting the leg portion of the arch. .
And since the end in the vehicle width direction of the inclined part is attached to the lower surface of the rear side frame, the rear impact load received by the rear subframe is transmitted to the rear side frame via the inclined part to distribute the load. Can do.
Thereby, the durability of the entire rear sub-frame with respect to the rear collision load can be ensured, and the forward movement of the rear sub-frame at the time of the rear collision can be suppressed.
In addition, the front cross member has a central portion that does not bend in the vertical direction, and extends in the vehicle width direction at a position immediately after the fuel tank. Therefore, the weight of the front cross member is increased to compensate for the static rigidity of the rear subframe. Thus, the NVH performance can be improved.
Therefore, the fuel tank can be protected without sacrificing the capacity of the fuel tank, the layout of the bottom of the vehicle body, the weight, and the NVH performance.

  In one embodiment of the present invention, the front cross member portion forms a substantially rectangular closed cross section, and the vertical wall portion of the inclined portion is disposed on the rear side of the vehicle along the longitudinal direction of the front cross member portion. Projecting ridges are formed.

  According to the said structure, even if the front side cross member part deform | transforms by a rear collision load, the protrusion to the fuel tank side ahead of a vehicle can be avoided reliably by a protruding item | line part. Thereby, a fuel tank can be protected more reliably.

  According to the present invention, the fuel tank can be protected without sacrificing the capacity of the fuel tank, the layout, weight, and NVH performance of the bottom of the vehicle body.

Bottom view showing the rear body structure of the automobile of the present invention 1 is a cross-sectional view taken along line AA in FIG. BB sectional view taken on line in FIG. A perspective view showing the rear subframe as seen from the front of the vehicle A perspective view showing the rear subframe as viewed from the rear of the vehicle Top view of the rear subframe Front view of rear subframe Rear view of rear subframe Side view of rear subframe 7A is a cross-sectional view taken along the line CC in FIG. 7, FIG. 7B is a cross-sectional view taken along the line D-D in FIG. 7, and FIG. , (D) is a sectional view taken along line FF in FIG. 7, and (e) is a sectional view taken along line GG in FIG. HH arrow sectional view of FIG. (A) is sectional drawing which shows the junction part of a side member part and a front inclination part, (b) is sectional drawing which shows the junction part of a side member part and a back inclination part. Explanatory drawing which shows the state at the time of rear collision typically Bottom view schematically showing the rear body structure of a conventional automobile A bottom view schematically showing a rear body structure of an automobile in which front end portions of left and right side member portions are connected to a front cross member portion.

  A rear sub having left and right side member portions and front and rear cross member portions for the purpose of protecting the fuel tank without sacrificing the capacity of the fuel tank, the layout, weight, and NVH performance of the bottom of the vehicle body. A rear body structure of an automobile provided with a frame, wherein the left and right side member portions have rear end portions attached to the lower surfaces of rear left and right rear side frames of the vehicle body, respectively, while front end portions are attached to the front cross member portion. A rear side member that extends forward inward in the vehicle width direction from the rear end mounting portion to a lower arm spring located rearward of the rear wheel axle of the rear wheel suspension, and forward of the vehicle in the vehicle width direction of the spring. A bent portion that bends toward the front, and a mounting portion from the bent portion to the front end portion on the inner side in the vehicle width direction from the rear side frame And a front side member extending substantially parallel to the front and rear of the vehicle body, and the front cross member portion is located at a front portion of the rear side frame immediately after a fuel tank disposed on a lower surface of the vehicle body. Extends in the vehicle width direction at the position of the vehicle, and has a central portion that is substantially straight in the vehicle width direction in a plan view of the vehicle, and is bent and extended obliquely outward and forward in the vehicle width direction from both ends of the central portion in the vehicle width direction. The both ends of the inclined portion in the vehicle width direction are mounted on the lower surfaces of the left and right rear side frames.

An embodiment of the present invention will be described in detail with reference to the drawings.
1 is a bottom view showing the rear body structure of the automobile, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG.

1 to 3, a rear floor 4 is connected to a rear portion of a center floor panel 1 via a rear seat pan 2 and a slant portion 3 that is inclined rearward and upward and extends in the vehicle front-rear direction. A spare tire pan 4a is formed at the center of the rear floor 4 in the vehicle width direction and has a circular shape in a plan view of the vehicle and protrudes downward. Here, a rear seat (seat cushion, seat back) is disposed in the passenger compartment space above the rear floor 4 behind the slant portion 3.
The above-described center floor panel 1 and the front floor panel (not shown) are integrally or integrally formed with a tunnel portion 5 that protrudes into the vehicle interior at the center in the vehicle width direction and extends in the front-rear direction of the vehicle. Side sills 6 are joined and fixed to both ends of the front floor panel in the vehicle width direction.

The side sill 6 is a vehicle body strength member having a side sill closed section that extends in the front-rear direction of the vehicle by joining and fixing the side sill inner and the side sill outer.
A rear side frame 7 extending in the front-rear direction of the vehicle is provided from the rear seat pan 2 to the slant portion 3 and the rear floor 4.

  The rear side frames 7 are provided on the left side and the right side of the vehicle, respectively, on the inner side in the vehicle width direction of the wheel house 8. The rear seat pan 2, the slant portion 3, and the rear floor 4 are provided between the left and right rear side frames 7, 7. Is provided. The rear side frame 7 includes a rear side frame upper 7U positioned on the upper surface side of each element 2, 3 and 4, and a rear side frame lower 7L positioned on the lower surface side of each element 2, 3 and 4. Between the rear side frame upper 7U and the rear side frame lower 7L and the elements 2, 3 and 4, a rear side closed section 70 (see FIG. 2) extending in the front-rear direction of the vehicle is formed.

  In the rear side frame 7, as shown in FIGS. 2 and 3, the lower surface of the rear side frame lower 7L extends substantially horizontally, while the upper surface of the rear side frame upper 7U is inclined forward and upward to extend in the vehicle front-rear direction. Yes. In accordance with the inclination of the upper surface of the rear side frame upper 7U, the floor surface of the rear floor 4 is also inclined forward and upward and extends in the vehicle front-rear direction.

The above-mentioned rear side frame 7 is a vehicle body strength member, and the front portion of the rear side frame 7 is connected to the side sill 6 at the kick-up portion, and the front portions of the left and right rear side frames 7 and 7 correspond to each other. A cross member 9 (so-called No. 3 cross member) extending in the vehicle width direction is stretched between them, and a closed cross section extending in the vehicle width direction is formed between the cross member 9 and the vehicle body floor panel. Yes.
Further, a vehicle body cross member 10 (so-called No. 4 cross member) is provided between the left and right rear side frames 7 and 7 at the front and rear intermediate portion of the rear side frame 7 corresponding to the rear portion of the slant portion 3 described above. Yes.

The vehicle body cross member 10 is positioned on the upper surface side of the slant portion 3 and connects the left and right rear side frame uppers 7U and 7U in the vehicle width direction, and is positioned on the lower surface side of the slant portion 3 Vehicle body cross member lower 10L for connecting the rear side frame lowers 7L, 7L in the vehicle width direction, and a closed cross section 11 extending in the vehicle width direction is formed between the vehicle body cross member upper 10U and the slant portion 3. The closed cross section 12 extending in the vehicle width direction is also formed between the vehicle body cross member lower 10L and the slant portion 3.
As shown in FIGS. 1 to 3, a fuel tank 14 is attached to the outside of the lower vehicle of the rear seat pan 2 and the slant portion 3 using a pair of tank bands 13 and 13.

On the other hand, as shown in FIG. 1, crash cans 15 and 15 are attached to the rear end portions of the pair of left and right rear side frames 7 and 7 so as to extend between the left and right crash cans 15 and 15 in the vehicle width direction. A bumper reinforcement 16 is laid horizontally.
Further, as shown in FIG. 1, a trailing arm mounting portion 17 is formed on the rear side frame lower 7 </ b> L so as to correspond to the front and rear cross members 9, 10, and is further rearward than the vehicle body cross member 10. Correspondingly, the rear side frame lower 7L is provided with a spring seat (not shown) of a suspension spring 27 (see FIG. 1) to be described later, and the rear side frame lower corresponding to the rear position further than the spring seat. At 7L, a mounting point for the rear vehicle body mounting portion 25 is provided.
Further, as shown in FIG. 1, a rear suspension damper mounting portion 20 is provided in the wheel house 8.
A rear subframe 21 (hereinafter simply referred to as subframe 21) is attached to the vehicle body structure shown in FIGS. 2 and 3 as shown in a bottom view in FIG.

4 is a perspective view showing the subframe 21 as seen from the front, FIG. 5 is a perspective view showing the subframe 21 as seen from the rear of the vehicle, FIG. 6 is a plan view of the subframe 21, and FIG. FIG. 8 is a rear view of the subframe 21, and FIG. 9 is a side view of the subframe 21.
As shown in FIGS. 4 to 9, the sub-frame 21 that supports the rear suspension includes left and right side member portions 22, 22, a front cross member portion 23, and a rear cross member portion 24.

The left and right side member portions 22 and 22 are formed in a pipe shape using a pipe member, and a rear vehicle body attachment portion 25 is provided at the rear end portion of the side member portion 22.
A rear vehicle body mounting portion 25 is provided at the rear end portion of the side member portion 22, and the rear end portions of the left and right side member portions 22, 22 are connected to the rear vehicle body mounting portion as shown in FIG. 1. The left and right rear side frames 7 are attached to the left and right rear side frames 7 (specifically, the attachment points of the rear side frame lower 7L), while the front end portions of the left and right side member portions 22 and 22 are joined to the front cross member portion 23 by joining. It is attached to the inner side in the vehicle width direction than the rear side frame 7.

  The side member portion 22 includes a side member rear portion 22R that extends inward in the vehicle width direction from the rear vehicle body attachment portion 25 to the suspension spring 27, and a bent portion 22C that is bent toward the vehicle front side in the vehicle width direction of the spring 27. And a side member front portion 22F extending substantially in parallel with the vehicle front-rear center line from the bent portion 22C to the joint portion of the front end portion to the front cross member portion 23 in the vehicle width direction from the rear side frame 7. doing.

  As shown in FIG. 1, each of the side member portions 22 described above extends from the rear vehicle body mounting portion 25 of the subframe 21 to the front in the vehicle width direction by the bent portion 22C and the side member front portion 22F. A suspension spring 27 can be disposed in front. Thereby, it is comprised so that coexistence with the dispersion | distribution of a rear-end collision load and the layout of the spring 27 for suspensions may be aimed at.

Further, the side member 22 has a side member front portion 22F below the rear floor 4 that is located on the inner side in the vehicle width direction from the rear side frame 7, as shown in FIGS. 2 to 5, 8, and 9, when viewed from the side of the vehicle. It is bent so as to protrude upward.
As shown in FIG. 9, the height position of the center line L1 (see FIG. 9) of the side member portion 22 at the joint portion of the front end portion is equal to the center line L2 ( It is set lower than the height position (see FIG. 9).

In the side member front portion 22F, a top portion 22T that protrudes most upward in a vehicle side view is formed at an intermediate portion between the bent portion 22C and the front end portion, and the rear floor 4 is inclined forward and upward as described above. As a result, a predetermined interval is formed between the top 22T and the rear floor 4.
Moreover, in the side member front part 22F, the site | part from the top part 22T to the front-end part inclines linearly in the vehicle front downward direction by the vehicle side view.

As shown in FIGS. 4 to 6, in the vehicle plan view, in the vicinity of the front end portion of the side member portion 22, an upper arm support portion 28 above the side member portion 22 and a lower arm spaced downward from the side member portion 22. A support portion 29 is provided.
The upper arm support portion 28, the lower arm support portion 29, and the front cross member portion 23 described above are disposed at positions that overlap in the front-rear direction, in this embodiment, at substantially the same position in the front-rear direction.

As shown in FIGS. 7 and 8, between the upper arm support portion 28 and the lower arm support portion 29 described above, the upper arm support portion 28 is mounted on the bracket 30 (details) on the upper side of the side member portion 22 and the front cross member portion 23. Are connected via an upper arm support bracket 30).
Further, the lower arm support portion 29 is connected to the lower portions of the side member portion 22 and the front cross member portion 23 via a bracket 31 (specifically, a lower arm support bracket 31).
That is, in the vicinity of the front end portion of the side member portion 22, support portions 28 and 29 for pivotally supporting the front arm of the suspension (the front upper arm not shown, the front lower arm 32 shown in FIGS. 1 and 12) are provided. The bracket 30 constituting the support portion 28 of the front upper arm of the suspension and the bracket 31 constituting the support portion 29 of the front lower arm 32 below the suspension 30 are extended in the vehicle width direction at a position overlapping in the front-rear direction. Is.

  1 to 3, the front cross member 23 described above extends in the vehicle width direction at a position immediately after the fuel tank 14 at the front portion of the rear side frame 7, as shown in FIGS. As shown in FIG. 7, a central portion 23 </ b> C that is substantially straight in the vehicle width direction in a plan view of the vehicle, and right and left inclined portions that are bent and extended obliquely forward from the both ends of the central portion 23 </ b> C in the vehicle width direction. 23S, 23S.

  10A to 10E are respectively a cross-sectional view taken along line CC, a cross-sectional view taken along line DD, a cross-sectional view taken along line EE, and a cross-sectional view taken along line FF in FIG. , G-G arrow sectional drawing. The front cross member portion 23 described above is configured by joining and fixing a front member 33 and a rear member 34. Specifically, as shown in a cross-sectional view in FIG. 10, both members 33 and 34 are bent in a substantially U-shaped cross section so that they are opposite to each other, and their upper and lower surfaces are partially overlapped and fixed to each other. Thus, a closed cross section 35 having a substantially rectangular cross section extending in the vehicle width direction is formed by both members 33 and 34, and the rigidity of the front cross member portion 23 is improved by this closed cross section structure.

  Further, in the inclined portion 23S of the front cross member portion 23, as shown in FIGS. 2 to 5, FIG. 7 to FIG. 9 and FIG. 10 (a), the vertical wall portions (front portion, Ribs 33a and 34a projecting rearward of the vehicle along the longitudinal direction of the front cross member portion 23 are formed on the rear surface portion. As shown in FIGS. 2, 4, 5, 7, and 9, the front cross member 23 (inclined portion 23 </ b> S) has a cylindrical shape that extends vertically in the closed cross-section 35 at the vehicle width direction end. The front vehicle body attachment portion 36 is attached.

  On the inner side in the vehicle width direction of the inclined portion 23S, as shown in FIGS. 2, 3, 5, 9, and 10 (b), a circular mounting hole 34b is formed in the rear member 34. A joining flange portion 34c that protrudes toward the rear of the vehicle by burring is formed at the peripheral portion. The front end portions of the left and right side member portions 22 are inserted into the mounting holes 34b, and are joined and fixed to the rear member 34 (inclined portion 23S) by the joining flange portions 34c.

  Further, as shown in FIG. 10C, the ribs 33a and 34a are not formed at the boundary portion between the inclined portion 23S and the central portion 23C, and the vertical wall portions of the front member 33 and the rear member 34 are substantially linear. There is no. In the central portion 23C, as shown in FIGS. 4, 7, 10D and 10E, the longitudinal wall portion (front surface portion) of the front member 33 extends along the longitudinal direction of the front cross member portion 23. As shown in FIGS. 5 and 10 (e), a rib 33b protruding forward of the vehicle is formed on the vertical wall portion (rear surface portion) of the rear member 34 along the longitudinal direction of the front cross member portion 23. Thus, a rib 34d protruding rearward of the vehicle is formed.

  Further, as shown in FIG. 4, FIG. 7, FIG. 8, and FIG. 10 (e), a push-up portion 23A that protrudes downward is formed in a part of the central portion 23C. The upper part of the jack is pressed when the vehicle is jacked up.

  On the other hand, as shown in FIG. 4, the above-described subframe 21 has a rear lower arm 37 (see FIGS. 1 and 2) at a position spaced rearward from the upper arm support portion 28, the lower arm support portion 29, and the front cross member portion 23. ) Is supported.

  As shown in FIGS. 4 to 9, the above-described rear cross member portion 24 is provided with a central portion 24 </ b> C in front of the rear vehicle body mounting portion 25 of the subframe 21, and the left and right rear sides of the central portion 24 </ b> C. The rear lower arms 37 and 37 of the suspension shown in FIGS. 1 and 2 are pivotally supported by the lower arm support portions 38 and 38. The rear lower arm 37 is located behind the axle of the rear wheel 48 (see FIG. 13) and controls the vertical movement of the rear wheel 48.

As shown in FIGS. 4 to 6, the side portion of the rear cross member portion 24 described above is inclined rearwardly extending from the center portion 24 </ b> C described above to the rear vehicle body mounting portion 25 side of the subframe 21 in plan view. Branching into a part 24R and a forward inclined part 24F extending inclined to the front side.
The rear inclined portion 24R and the front inclined portion 24F corresponding to the left and right side portions of the rear cross member portion 24 are branched in the front-rear direction from the rear lower arm support portions 38, 38, and each branched inclined portion 24R is branched. 24F, both ends in the vehicle width direction are connected to the side member portion 22 described above, and a truss structure is formed by the three members of the side member portion 22, the front inclined portion 24F, and the rear inclined portion 24R. The truss structure is used to reinforce the sub-frame 21 so as to reinforce the support rigidity of the rear lower arm 37, particularly the static rigidity in the normal direction, in the front-rear and left-right directions while suppressing an increase in weight.

  FIG. 11 is a cross-sectional view taken along line HH in FIG. 8, and the rear cross member portion 24 described above is configured by joining and fixing a front member 39 and a rear member 40. In particular, in the central portion 24C of the rear cross member portion 24 shown in a sectional view in FIG. 11, both members 39, 40 are bent in a substantially U-shaped cross section so that they are opposite to each other. By partially overlapping and fixing each other, the members 39 and 40 form a closed cross section 41 having a substantially rectangular cross section extending in the vehicle width direction, and the rigidity of the central portion 24C is improved by this closed cross section structure.

  Further, at the front inclined portion 24F and the rear inclined portion 24R, the outer end portions in the vehicle width direction of the front member 39 and the rear member 40 are bent into a substantially L shape (here, a substantially inverted L shape) so as to be opposite to each other. Thus, the side end portions 24E1 and 24E2 are formed, and the side end portions 24E1 and 24E2 are joined to the side member portion 22.

  12A is a cross-sectional view showing a joint portion between the side member portion 22 and the front inclined portion 24F, and FIG. 12B is a cross-sectional view showing a joint portion between the side member portion and the rear inclined portion 24R. In the forward inclined portion 24F, as shown in FIG. 12A, the side end portion 24E1 having a substantially L shape is a portion on the inner side in the vehicle width direction of the center line L3 at the top portion 22T (specifically, the center line L3 In the vehicle width direction inside the vertical line L4 in the vertical direction passing through the vehicle. Further, in the rearward inclined portion 24R, as shown in FIG. 12B, the side end portion 24E2 having a substantially L shape is a portion on the inner side in the vehicle width direction with respect to the center line L5 at the bent portion 22C (in detail, It is joined to the vertical direction virtual line L6 passing through the center line L5.

  By the way, in the rear side closed cross section 70 of the rear side frame 7, as shown in FIG. 2, a first reinforcement 42U having a substantially hat-shaped cross section with an open upper portion and a first cross section having a substantially hat-shaped cross section with a lower opened. 2 reinforcements 42L are provided, and the front and rear ends thereof are joined to the rear side frame upper 7U and the rear side frame lower 7L. And in each reinforcement 42U and 42L, the stat bolt 43 is penetrated in the state which the bottom face and the upper surface mutually contacted, and reinforcement 42U and 42L are fastened by this stat bolt 43.

  Corresponding to the reinforcements 42U and 42L, a mounting seat 44 bulging downward therefrom is joined to the lower surface of the rear side frame lower 7L, and the above-mentioned stat bolt 43 faces downward from the mounting seat 44. Protruding.

As shown in FIG. 2, a stat bolt 43 is inserted into the front vehicle body attachment portion 36 of the front cross member portion 23 (inclined portion 23S) of the subframe 21, and the front cross member portion 23 (front vehicle body attachment portion 36). Is fastened and fixed to the stat bolt 43 from below using a nut 45. Similarly, the rear vehicle body mounting portion 25 is fastened and fixed to the rear side frame lower 7L from below using bolts 46.
Further, as shown in FIGS. 1 and 3, the rear lower arm 37 described above is formed so as to bulge out at a portion facing the spring seat on the rear side frame lower 7L side in the vertical direction so that it also serves as the spring seat of the spring 27. Yes.

  In FIG. 1, reference numeral 47 denotes a disc wheel for holding a rear wheel 48 (see FIG. 13), and 49 denotes a trailing arm attached between the trailing arm attachment portion 17 (see FIG. 2) and a wheel support.

FIG. 13 is an explanatory view schematically showing the state at the time of rear collision, and since the front end portions of the left and right side member portions 22 are attached to the front cross member portion 23, the front end portions of the left and right side member portions 22 A sufficient distance from the fuel tank 14 can be secured.
Further, as shown by an arrow in FIG. 13, a rear collision load is input to the sub-frame 21 at the time of rear collision, and the front cross member portion 23 is formed with a central portion 23 </ b> C that is substantially straight in the vehicle width direction in the vehicle plan view. Since the central portion 23C is substantially arched in plan view of the vehicle by the inclined portion 23S that is bent and extended obliquely forward and outward in the vehicle width direction from both ends in the vehicle width direction, the inclination that constitutes the leg portion of the arch The rear impact load can be firmly received by the portion 23S.
Since the end in the vehicle width direction of the inclined portion 23S is attached to the lower surface of the rear side frame 7, the rear impact load received by the subframe 21 is transmitted to the rear side frame 7 via the inclined portion 23S. Dispersion can be achieved.
Thereby, durability of the whole sub-frame 21 with respect to a rear collision load can be ensured, and the advance of the sub-frame 21 at the time of a rear collision can be suppressed.

  Further, in this embodiment, in the side member portion 22, the side member front portion 22F on the inner side in the vehicle width direction from the rear side frame 7 is bent so as to protrude upward in a vehicle side view. As shown by a two-dot chain line in FIGS. 2 and 3, the side member portion 22 can be bent and deformed starting from a top portion 22T that protrudes most upward in a side view of the vehicle, and effectively absorbs a rear-end collision load. Can do. Thereby, the advance of the sub-frame 21 at the time of a rear collision can be suppressed.

Furthermore, since the front cross member portion 23 extends in the vehicle width direction at a position immediately after the fuel tank 14 without the central portion thereof being bent in the vertical direction, the front cross member portion 23 is used to supplement the static rigidity of the subframe 21. NVH performance can be improved while avoiding an increase in weight.
In the figure, arrow F indicates the front of the vehicle, and arrow R indicates the rear of the vehicle. In the drawing, an arrow IN indicates an inner direction in the vehicle width direction, and an arrow OUT indicates an outer direction in the vehicle width direction.

  Thus, the rear body structure of the automobile of the embodiment includes the sub-frame 21 having the left and right side member portions 22 and 22 and the front and rear cross member portions 23 and 24, and the left and right side member portions 22. , 22 have rear end portions attached to the lower surfaces of the left and right rear side frames 7, 7 at the rear of the vehicle body, and a front end portion attached to the front cross member portion 23, and a suspension of the rear wheel 48 from the rear vehicle body attachment portion 25. A side member rear portion 22R extending inward in the vehicle width direction to the spring 27 of the rear lower arm 37 positioned rearward of the vehicle from the rear axle, and a bent portion 22C bent toward the vehicle front side in the vehicle width direction of the spring 27; In the vehicle width direction inner side than the rear side frame 7, from the bent portion 22C to the mounting portion at the front end portion is substantially parallel to the vehicle front-rear center line in the vehicle plan view. The front cross member portion 23 extends in the vehicle width direction at a position immediately after the fuel tank 14 disposed on the lower surface of the vehicle body in the front portion of the rear side frame 7. A central portion 23C that is substantially straight in the vehicle width direction in a plan view of the vehicle, and an inclined portion 23S that is bent and extends obliquely forward and outward in the vehicle width direction from both ends of the central portion 23C in the vehicle width direction, Both end portions in the vehicle width direction of the inclined portion 23S are attached to the lower surfaces of the left and right rear side frames 7 (see FIGS. 1 to 7, 9, 10, and 13).

According to this configuration, since the front end portions of the left and right side member portions 22 are attached to the front cross member portion 23, it is possible to ensure a sufficient distance between the front end portions of the left and right side member portions 22 and the fuel tank 14. it can.
In addition, a rear collision load is input to the subframe 21 at the time of a rear collision, and the front cross member portion 23 includes a central portion 23C that is substantially linear in the vehicle width direction in a plan view of the vehicle, and a vehicle width direction of the central portion 23C. Since the inclined portion 23S that is bent and extended obliquely forward and outward in the vehicle width direction from both ends forms a substantially arch shape in plan view of the vehicle, the inclined portion 23S constituting the leg portion of the arch strongly strengthens the rear impact load. Can take it.
Since the end in the vehicle width direction of the inclined portion 23S is attached to the lower surface of the rear side frame 7, the rear impact load received by the subframe 21 is transmitted to the rear side frame 7 via the inclined portion 23S. Dispersion can be achieved.
Thereby, durability of the whole sub-frame 21 with respect to a rear collision load can be ensured, and the advance of the sub-frame 21 at the time of a rear collision can be suppressed.
Furthermore, since the front cross member portion 23 extends in the vehicle width direction at a position immediately after the fuel tank 14 without the central portion thereof being bent in the vertical direction, the front cross member portion 23 is used to supplement the static rigidity of the subframe 21. NVH performance can be improved while avoiding an increase in weight.
Therefore, the fuel tank 14 can be protected without sacrificing the capacity of the fuel tank 14, the layout, weight, and NVH performance of the bottom of the vehicle body.

  In the embodiment of the present invention, the front cross member portion 23 forms a substantially rectangular closed cross section 35, and the vertical wall portion of the inclined portion 23 </ b> S is located on the rear side of the vehicle along the longitudinal direction of the front cross member portion 23. The ribs 33a and 34a projecting are formed (see FIGS. 2 to 5 and 7 to 10).

  According to this configuration, even if the front cross member 23 is deformed by a rear collision load, the protrusion toward the fuel tank 14 in front of the vehicle can be reliably avoided by the ribs 33a and 34a. Thereby, the fuel tank 14 can be more reliably protected.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The rear subframe of the present invention corresponds to the subframe 21 of the embodiment,
Similarly,
The lower arm corresponds to the rear lower arm 37,
The ridges correspond to the ribs 33a and 34a,
The present invention is not limited to the configuration of the above-described embodiment.
For example, in the above-described embodiment, the ribs 33a and 34a (projection strips) are formed on the front and rear vertical wall portions of the front cross member portion 23 (inclined portion 23S), but at least only on the front vertical wall portion. It is only necessary to form the ribs 33a (protrusions).

  As described above, the present invention is useful for a rear body structure of a vehicle including a rear subframe having left and right side member portions and front and rear cross member portions.

7 ... Rear side frame
14 ... Fuel tank
21 ... Subframe
22 ... Side member
22C ... bent portion
22F ... Side member front
22R ... Side member rear
23: Front cross member
23C ... Central part
23S ... inclined part
24 ... Rear cross member
27 ... Spring
33a, 34a ... ribs
35 ... Closed section
37 ... Rear lower arm

Claims (2)

A rear vehicle body structure including a rear subframe having left and right side member portions and front and rear cross member portions,
Each of the left and right side member portions has rear end portions attached to the lower surfaces of the left and right rear side frames at the rear of the vehicle body,
A front end is attached to the front cross member,
A side member rear portion extending from the rear end attachment portion to the front in the vehicle width direction from the rear wheel axle of the rear wheel suspension to the lower arm spring located at the rear of the vehicle;
A bent portion that is bent toward the front of the vehicle on the inner side in the vehicle width direction of the spring;
On the inner side in the vehicle width direction from the rear side frame, it has a vehicle front-rear center line and a side member front portion extending substantially in parallel with the vehicle plan view from the bent portion to the mounting portion of the front end portion,
The front cross member portion extends in the vehicle width direction at a position immediately after the fuel tank disposed on the lower surface of the vehicle body at the front portion of the rear side frame.
A central portion that is substantially straight in the vehicle width direction in plan view of the vehicle;
A slanted portion extending obliquely from the both ends of the central portion in the vehicle width direction to the front outside in the vehicle width direction;
Both end portions in the vehicle width direction of the inclined portion are rear vehicle body structures attached to the lower surfaces of the left and right rear side frames. The front cross member portion forms a substantially rectangular closed cross section,
The rear body structure of the automobile according to claim 1, wherein the vertical wall portion of the inclined portion is formed with a ridge portion protruding rearward of the vehicle along a longitudinal direction of the front cross member portion.

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