Vehicle lower body structure

Abstract

To provide a vehicle lower body structure that can provide improved appearance by preventing a silencer from being seen from a vehicle rear side and provide improved aerodynamic characteristics by preventing underfloor travel wind from being engulfed at a rear side of a rear bumper.SOLUTION: A shielding member 60 is disposed between a rear bumper 4 and a silencer 10. The shielding member 60 is disposed to extend in a vehicle width direction while overlapping with at least a rear vertical wall 10b of the silencer 10 in an up-down direction when viewed from a vehicle rear side. The shielding member 60 is provided with a guide portion 62 that guides underfloor travel wind flowing rearward under the silencer 10 to flow downward.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a lower body structure of a vehicle having a silencer disposed transversely in front of a lower portion of a rear bumper so as to extend in the vehicle width direction. [Background technology]

[0002] Conventionally, there is known a vehicle equipped with a silencer that is disposed transversely so as to extend in the vehicle width direction in front of the lower part of the rear bumper of the above-mentioned example. In this case, if the lower end of the silencer is positioned lower than the lower end of the rear bumper, the silencer will be visible when viewed from behind, making the vehicle look unsightly, especially when the night lights of following vehicles hit the silencer and reflect off it.

[0003] In addition, the rear bumper area described above had the problem that the underfloor wind flowing under the vehicle from the front to the rear of the vehicle was caught in the lower rear part of the rear bumper, causing a deterioration in the Cd value (air drag coefficient) in the aerodynamic characteristics.

[0004] Incidentally, Patent Document 1 discloses a vehicle lower body structure in which an undercover is provided between a rear bumper and a silencer, and the undercover is configured to improve aerodynamic performance.

[0005] The conventional vehicle lower body structure disclosed in Patent Document 1 has the advantage of being able to improve aerodynamic characteristics, but on the other hand, the undercover is located above the lower end of the rear bumper and at the front of the vehicle, and the silencer is visible when viewed from behind the vehicle, which causes the vehicle to look unsightly. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6052229 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the present invention aims to provide a lower body structure for a vehicle that can reduce the visibility of the silencer from the rear of the vehicle, improving its appearance, and also reduce the ingestion of wind from running under the floor behind the rear bumper, thereby improving aerodynamic characteristics. [Means for solving the problem]

[0008] The present invention is a lower body structure for a vehicle having a silencer disposed transversely so as to extend in the vehicle width direction in front of a lower portion of a rear bumper, and a shielding member is provided between the rear bumper and the silencer, and the shielding member is ,car The shielding member is provided so as to extend in the width direction, and A shielding surface overlaps with at least the rear vertical wall of the silencer in a rear view of the vehicle, and a The above silencer of A guide surface that guides the underfloor airflow downward as it flows rearward underneath. The guide surface and the shielding surface are provided offset in the vehicle longitudinal direction, and a blow-out hole is provided between the shielding surface and the guide surface to guide downward and blow out the running wind flowing rearward through the upper part of the silencer. The vehicle lower body structure is characterized in that

[0009] This invention reduces the visibility of the silencer from the rear of the vehicle, improving the appearance, and also reduces the ingestion of underfloor wind behind the rear bumper, improving aerodynamic characteristics. Specifically, since the shielding member overlaps at least the rear vertical wall of the silencer when viewed from the rear of the vehicle, the silencer is prevented from being seen from the rear of the vehicle, thereby improving its appearance.

[0010] Furthermore, the shielding member is provided with a guide surface that guides downward the underfloor traveling wind that flows below the silencer from the front to the rear of the vehicle, so that the underfloor traveling wind can be deflected downward to prevent it from being drawn in behind the rear bumper, thereby improving aerodynamic characteristics. 。

[0011] Furthermore, as mentioned above,The shielding member includes a shielding surface that overlaps with at least the rear vertical wall of the silencer in a rear view of the vehicle, and a guide surface that is located forward of the shielding surface and guides downward underfloor traveling wind that flows rearward through a lower portion of the silencer, and the guide surface and the shielding surface are offset in the front-rear direction of the vehicle. It is something .

[0012] this composition This has the following effects: In other words, although the shielding function required of the shielding surface and the guide function required of the guide surface are originally different, by offsetting the guide surface and the shielding surface in the fore-and-aft direction of the vehicle, it is possible to ensure the functions that meet each requirement.

[0013] Furthermore, as described above, since the blowing holes are formed between the shielding surface and the guide surface, the wind blown out from the blowing holes formed between the shielding surface and the guide surface pushes the underfloor traveling wind downward, thereby suppressing the entrainment of underfloor traveling wind behind the rear bumper and improving aerodynamic characteristics.

[0014] As an aspect of the present invention, the guide surface may be provided on the front edge of the blow-out hole, protruding downward from the peripheral portion of the front edge, and the shielding surface may be provided on the rear edge of the blow-out hole, protruding downward from the peripheral portion of the rear edge.

[0015] As another aspect of the present invention, the guide surface and the shielding surface may be provided in a protruding shape so that their lower ends are at the same position.

[0016] In another aspect of the present invention, the height of the lower rear end position where the underfloor traveling wind flowing rearward through the lower part of the silencer separates rearward from the lower part of the silencer is defined as the silencer lower rear end height, and the peripheral parts of the front edge and the rear edge are both positioned higher than the silencer lower rear end height, and the guide surface and the shielding surface both protrude downward to a height equivalent to the silencer lower rear end height.

[0017] In another aspect of the present invention, the shielding surface may be formed in an inclined shape so that the lower portion thereof is positioned more forward of the vehicle, and the guide surface may be formed in an inclined shape so that the lower portion thereof is positioned more rearward of the vehicle. According to this invention, it is possible to form the inclined shielding surface and the inclined guide surface in accordance with the requirements for the shielding surface and the guide surface, respectively. 。

[0018] difference Furthermore, as an aspect of the present invention, the blowout hole may be formed in the shape of a slit that is long in the vehicle width direction at the vehicle width central portion of the shielding member. This invention fully ensures that the wind blowing out from the slit-shaped outlet holes, which are long in the vehicle width direction, can push down the wind generated by underfloor travel in the center of the vehicle width, and more reliably prevents the wind from being drawn in behind the rear bumper. [Effects of the Invention]

[0019] According to this invention, it is possible to reduce the visibility of the silencer from the rear of the vehicle, improving the appearance, and it is also possible to reduce the ingestion of wind from traveling under the floor behind the rear bumper, thereby improving the aerodynamic characteristics. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. [Figure 2] FIG. 2 is a side view of the left side of the vehicle showing the lower body structure of the vehicle. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 3 is a perspective view of a main portion showing the mounting structure of the first and second under-cover members. [Figure 6] FIG. 4 is a bottom perspective view of the second under-cover member. [Figure 7] Cross-sectional view taken along line AA in Figure 1. [Figure 8] FIG. 8 is a bottom view of the main part of FIG. 7. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 4 is a cross-sectional view of the shielding member at the center in the vehicle width direction. DETAILED DESCRIPTION OF THE INVENTION

[0021] The purpose of the lower body structure of a vehicle is to prevent the silencer from being seen from the rear of the vehicle, improve the appearance, and to prevent the underfloor wind from being drawn in behind the rear bumper, thereby improving the aerodynamic characteristics. The lower body structure of a vehicle is provided with a silencer that is horizontally disposed so as to extend in the vehicle width direction at the lower front of the rear bumper, and a shielding member is provided between the rear bumper and the silencer. ,car The shielding member is provided so as to extend in the width direction, and A shielding surface overlaps with at least the rear vertical wall of the silencer in a rear view of the vehicle, and a The above silencer ofA guide surface that guides the underfloor airflow downward as it flows rearward underneath. and the guide surface and the shielding surface are provided offset in the vehicle longitudinal direction, and a blow-out hole is provided between the shielding surface and the guide surface to guide downward and blow out airflow flowing rearward through an upper portion of the silencer. This was realized by providing the following configuration. [Example]

[0022] An embodiment of the present invention will be described in detail below with reference to the drawings. The drawings show the vehicle underbody structure, with Fig. 1 being a bottom view of the vehicle underbody structure, Fig. 2 being a side view of the left side of the vehicle showing the vehicle underbody structure, and Fig. 3 being a rear view of the vehicle underbody structure. Also, Fig. 4 is a perspective view of the rear suspension device, Fig. 5 is a perspective view of the main parts showing the mounting structure of the first and second undercover members, and Fig. 6 is a bottom perspective view of the second undercover member.

[0023] In Figure 2, a kick-up section is provided that rises upward from the rear end of the front floor panel, and a rear floor panel 1 is provided at this kick-up section and extends rearward from the kick-up section. This rear floor panel 1 forms the floor surface of the passenger compartment and luggage compartment, and a rear seat pan 2 is integrally formed with the rear floor panel 1.

[0024] From the rear end of the rear floor panel 1 to the rear end of the front floor panel, rear side frames 3 having a two-piece front and rear structure extending in the longitudinal direction of the vehicle are provided on both left and right ends of these floor panels in the vehicle width direction.

[0025] Side sills (not shown) are provided that are continuous with the above-mentioned rear side frames 3 and extend forward of the vehicle, with the rear ends of the side sills overlapping the front ends of the rear side frames 3. Both the above-mentioned rear side frames 3 and side sills are vehicle body strength members.

[0026] On the other hand, as shown in FIGS. 1 to 3, a rear bumper 4 is attached to the rear of the vehicle in order to reduce the impact in the event of a rear-end collision. The rear bumper 4 is a resin injection-molded part attached along the lower rear edge of the vehicle. The rear bumper 4 covers the rear body structure, which is made up of the rear bumper reinforcement, the rear portion of the rear floor panel 1, the rear portions of the rear side frames 3, the rear end panel, etc., as well as the silencer 10, which will be described later, from the rear.

[0027] As shown in Figures 1 to 3, the rear bumper 4 has a main wall portion 4A that covers the middle portion of the rear body structure in the vehicle width direction, and side wall portions 4B that extend from the end portions of the main wall portion 4A in the vehicle width direction toward the front of the vehicle and cover the left and right corner portions of the rear body structure.

[0028] As shown in Figure 3, the main wall portion 4A of the rear bumper 4 is composed of an upper wall portion 5, a middle wall portion 6, and a lower wall portion 7. The upper end of the upper wall portion 5 is attached along the upper end of the rear end panel. The middle wall portion 6 extends in the vertical direction and the vehicle width direction, continuing from the lower part of the upper wall portion 5. The lower wall portion 7 extends in the vertical direction and the vehicle width direction, continuing from the lower part of the middle wall portion 6. A lower piece portion 7a located at the lower end of the lower wall portion 7 is located rearward of the rear end panel in the front-to-rear direction and lower than the rear floor panel 1 in the vertical direction.

[0029] The rear bumper 4 described above has a lower corner wall 4C that is continuous with the outer side of the lower wall portion 7 in the vehicle width direction and the lower part of the side wall portion 4B, and an opening 8 is formed in the rear surface of this lower corner wall 4C to release exhaust gases discharged from tailpipes 12, 13 (described later) to the rear of the vehicle.

[0030] The vehicle in this embodiment is a front-engine, rear-wheel drive (FR) vehicle, and therefore has a tunnel section 9 in the center of the front floor panel in the width direction, which extends in the longitudinal direction of the vehicle and protrudes into the passenger compartment (see Figure 1).

[0031] As shown in FIG. 1, a silencer 10 is provided at the front of the lower part of the rear bumper 4 as a noise suppressing device, and is disposed transversely so as to extend in the vehicle width direction. As shown in the figure, the silencer 10 has an inlet pipe 11 at the center of the front part in the vehicle width direction for introducing exhaust gas into the silencer 10, and tail pipes 12, 13 that are L-shaped when viewed from the bottom are provided on both left and right ends of the silencer 10 in the vehicle width direction, with rear end portions 12a, 13a of the tail pipes 12, 13 facing the opening 8 in the rear bumper 4. Also, as shown in Figures 1 to 3, the lower surface 10a of the silencer 10 is formed in a substantially flat shape.

[0032] A rear suspension device 20 that independently suspends left and right rear wheels (not shown) is provided below the pair of left and right rear side frames 3 (see FIG. 4). In this embodiment, a multi-link rear suspension is used as the rear suspension device 20.

[0033] As shown in Figure 4, the above-mentioned rear suspension device 20 includes a suspension cross member 24 (so-called subframe) that combines a front cross member 21, a rear cross member 22, and a pair of left and right side cross members 23, 23 in a well crib shape when viewed from above the vehicle.

[0034] The front cross member 21 connects the front sides of the pair of left and right side cross members 23, 23 in the vehicle width direction, and the rear cross member 22 connects the rear sides of the pair of left and right side cross members 23, 23 in the vehicle width direction.

[0035] The above-mentioned side cross member 23 extends in the fore-and-aft direction of the vehicle, and the portion of the side cross member 23 in front of the connection point with the front cross member 21 extends forward of the vehicle and outward in the vehicle width direction, and a vehicle body mounting member 25 is provided at the front end of the side cross member 23.

[0036] The side cross members 23 extend rearward and outward in the vehicle width direction from the connecting portion with the rear cross member 22, and a vehicle body mounting member 26 is provided at the rear end of the side cross members 23.

[0037] The multi-link rear suspension has five suspension links on each side: 27, 28, 29, 30, and 31. These five suspension links 27, 28, 29, 30, and 31 include three lower links 27, 28, and 29 located on the lower side and two upper links 30 and 31 located on the upper side, and the five suspension links 27 to 31 on each side connect the suspension cross member 24 to a wheel support member (not shown) for the rear wheel.

[0038] The three lower links located on the lower side include a lower lateral link 27, a toe control link 28 located rearward of the lower lateral link 27, and a lower rear rail link 29 located forward of the lower lateral link 27. The two upper links located on the upper side include an upper lateral link 30 and an upper trail link 31 located forward of the upper lateral link 30.

[0039] The lower lateral link 27 extends in the vehicle width direction from the attachment portion 32 towards the outside of the vehicle body, and an end portion 27a on the rear wheel side is connected to the wheel support member. The toe control link 28 extends from the mounting portion outward from the vehicle body at a forward incline, and an end portion 28a on the rear wheel side is connected to the wheel support member.

[0040] The lower rear rail link 29 extends from the attachment portion outward from the vehicle body at a rearward incline, and an end portion 29a on the rear wheel side is connected to the wheel support member. The upper link 30 extends from the mounting portion 33 outwardly of the vehicle body at a forward incline, and an end portion 30a on the rear wheel side is connected to a wheel support member. The upper trail link 31 extends from the mounting portion 34 outwardly of the vehicle body at a rearward incline, and an end portion 31a on the rear wheel side is connected to a wheel support member.

[0041] 2, the suspension cross member 24 is fixed to the lower part of the rear side frame 3 via front and rear body mounting members 25, 26. A mounting seat 35 is provided on the lower part of the rear side frame 3 that faces the front end body mounting member 25 in the vertical direction, and the body mounting member 25 at the front end of the suspension cross member 24 is fixed to the mounting seat 35.

[0042] The above-described rear suspension system 20 includes a suspension damper 36 . The suspension damper 36 includes a strut 37 and a coil spring stretched between the upper and lower seats. The upper end of the suspension damper 36 is attached to the rear side frame 3, and the lower end of the suspension damper 36 is attached to the lower lateral link 27.

[0043] That is, the multi-link rear suspension device 20 has a total of five sets of suspension links (a lower lateral link 27, a toe control link 28, a lower trail link 29, an upper lateral link 30, and an upper trail link 31), and each of these suspension links 27 to 31 is arranged to extend inward in the vehicle width direction from a position below the wheelhouse.

[0044] As shown in FIG. 4, a stabilizer 40 is held at the rear of the side cross member 23 using a bracket 38 and a holder 39. The stabilizer 40 suppresses the roll angle (for example, when a vehicle turns a corner, the body tilts, and this tilt angle is called the roll angle) of only one wheel when bumping or rebounding due to the resistance of its torsional rigidity.

[0045] Furthermore, a bracket 41 is provided at the lower part of the front end of the vehicle body mounting member 25, extending forward from the lower part toward the outside of the vehicle. Of the above-mentioned suspension links (lower lateral link 27, toe control link 28, lower trail link 29, upper lateral link 30, upper trail link 31), lower lateral link 27, which serves as a pair of first suspension links on the left and right, is configured with a U-shaped cross section with an open top surface, as shown in FIG. 5.

[0046] In other words, as shown in Figure 5, the above-mentioned lower lateral link 27 is configured by connecting a front wall 27b, a bottom wall 27c (see Figure 2), and a rear wall 27d in a U-shaped cross section, and is provided with a flange portion 27e extending from the upper end of the front wall 27b toward the front of the vehicle, and a flange portion 27f extending from the upper end of the rear wall 27d toward the rear of the vehicle.

[0047] As shown in FIG. 5, upper wall members 27h having elongated holes 27g through which struts 37 of suspension dampers 36 are inserted are welded to front and rear flange portions 27e, 27f on the upper surface of lower lateral link 27. Upper wall members 27h improve the rigidity of lower lateral link 27 while allowing vertical displacement of lower lateral link 27.

[0048] As shown in Figures 1, 2 and 5, a first undercover member 51 is provided on the rear side of the lower lateral link 27, covering the underside of the vehicle body while being flush with the underside of the lower lateral link 27, i.e., the underside of the bottom wall 27c.

[0049] As a result, deterioration of aerodynamic characteristics is suppressed by the space-saving first under-cover member 51, which is flush with the underside of the lower lateral link 27 and makes effective use of the underside of the lower lateral link 27. In other words, by using the underside of the lower lateral link 27 as part of the under-cover section, the area of ​​the first under-cover member 51 is reduced accordingly, thereby achieving space savings and suppressing underfloor traveling wind from being drawn into the rear suspension unit 20 and its surrounding areas by the first under-cover member 51.

[0050] As shown in FIG. 5, the first undercover member 51 includes a bottom wall 51a, a plurality of truncated cone-shaped mounting seats 51b formed to protrude upward from the bottom wall 51a, and a plurality of ribs 51c extending radially and connecting the outer periphery of the mounting seats 51b to the bottom wall 51a.

[0051] Meanwhile, a plurality of mounting pieces 42 are integrally formed on the rear wall 27d of the lower lateral link 27. Then, the first under-cover member 51 is attached to the lower lateral link 27 by connecting and fixing the mounting seats 51b of the first under-cover member 51 to the mounting pieces 42 of the lower lateral link 27 using mounting members 43 such as bolts and nuts.

[0052] As shown in Figures 1 and 5, of the above-mentioned suspension links (lower lateral link 27, toe control link 28, lower rear rail link 29, upper lateral link 30, upper trail link 31), lower rear rail link 29, which serves as the other pair of left and right second suspension links located further forward of the vehicle than lower lateral link 27, is provided with a second undercover member 52 that covers the underside of the vehicle body and is flush with the underside of lower lateral link 27.

[0053] As a result, the second under-cover member 52 and the first under-cover member 51 positioned at the front and rear are configured to further suppress deterioration of the aerodynamic characteristics. As shown in FIG. 5, the second undercover member 52 includes a bottom wall 52a, a plurality of truncated cone-shaped mounting seats 52b formed to protrude upward from the bottom wall 52a, and a plurality of ribs 52c extending radially and connecting the outer periphery of the mounting seats 52b to the bottom wall 52a.

[0054] On the other hand, the lower rear rail link 29 is formed with an inverted U-shaped cross section, and multiple mounting pieces 44 extending in the longitudinal direction of the vehicle are integrally formed from the lower ends of the front and rear walls of this lower rear rail link 29. Then, the second under-cover member 52 is attached to the lower rear rail link 29 by connecting and fixing the mounting seats 52b of the second under-cover member 52 to the mounting pieces 44 of the lower rear rail link 29 using mounting members 45 such as bolts and nuts.

[0055] Figure 6 is a perspective view of the underside of the second under-cover member 52. As shown in the figure, the underside of the second under-cover member 52 is provided with a plurality of ribs 52d that protrude downward from the vehicle and extend in the fore-and-aft direction of the vehicle, and are parallel to one another.

[0056] As a result, the above-mentioned multiple ribs 52d prevent the underfloor traveling wind flowing under the second under-cover member 52 from flowing from the front of the vehicle to the rear of the vehicle from escaping to the left and right in the vehicle width direction, thereby improving the streamlining effect and also increasing the rigidity of the second under-cover member 52 with the ribs 52d.

[0057] As shown in FIG. 1, a third under-cover member 53 that covers the underside of the vehicle body is provided on the vehicle width inner side of the second under-cover member 52, on the vehicle width inner side of the base end side of the front portion of the vehicle of the lower lateral link 27, and on the vehicle width inner side of the mounting portion 32 of the lower lateral link 27. This, together with the first and second under-cover members 51 and 52 which are the other under-cover members, further improves the effect of rectifying the underfloor running wind.

[0058] As shown in Figure 4, the above-mentioned third under-cover member 53 is supported on the suspension cross member 24 via a stay 46 located on the front lower part of the side cross member 23 of the suspension cross member 24, and a support bracket 47 located below the vehicle width direction end of the front cross member 21.

[0059] As shown in Figures 3 and 5, the underside of lower lateral link 27, which serves as the first suspension link, is provided with a curved portion 48 that protrudes downward from the free end thereof, and a curved portion 49 that protrudes upward from this curved portion 48 to the longitudinal middle portion of lower lateral link 27.

[0060] The bottom wall 51a of the above-mentioned first under-cover member 51 is provided with curved portions 54, 55 that follow the curved portions 48, 49 of the lower lateral link 27. As a result, the curved portions 54, 55 of the first under-cover member 51 follow the curved shape of the underside of the lower lateral link 27 serving as the first suspension link, ensuring a function of rectifying wind that flows under the floor when the vehicle is traveling.

[0061] As shown in FIG. 1, in the lower left side of the vehicle, a fourth under-cover member 56 is provided in front of the second and third under-cover members 52, 53, covering the underside of the vehicle body from the lower left end of the tunnel section 9 in the vehicle width direction to the lower part of the side sill outer.

[0062] 1, a fifth under-cover member 57 is provided on the lower right side of the vehicle, in front of the second and third under-cover members 52, 53, covering the underside of the vehicle body from the lower right end of the tunnel section 9 in the vehicle width direction to the lower part of the side sill outer. These fourth and fifth under-cover members 56, 57 are each attached and supported by the body.

[0063] 7 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 8 is a bottom view of the main part of FIG. 7, FIG. 9 is a bottom view of the shielding member, FIG. 10 is a top perspective view of the shielding member, and FIG. 11 is a cross-sectional view of the center part of the shielding member in the vehicle width direction. As shown in FIG. 7, the rear side frame 3 includes an upper rear side frame 3A located on the upper part of the rear floor panel 1 and a lower rear side frame 3B located on the lower part of the rear floor panel 1.

[0064] As shown in FIG. 7, the silencer 10 is constructed by joining a lower flange of a silencer upper case 14 and an upper flange of a silencer lower case 15, and the silencer 10 is supported on the rear side frame lower 3B using a plurality of hanger members 16.

[0065] 7 and 8, a cover member 60 is provided as a shielding member between a lower piece 7a extending in the vehicle longitudinal direction in the lower wall portion 7 of the rear bumper 4 and the rear portion of the silencer 10.

[0066] As shown in FIGS. 7 and 8, the cover member 60 is provided so as to extend in the vehicle width direction and overlap at least the rear vertical wall 10b of the silencer 10 in the vertical direction when viewed from the rear of the vehicle. That is, as shown in FIG. 7, the cover member 60 has a cover surface 61 as a shielding surface that overlaps in the vertical direction with the rear vertical wall 10b of the silencer 10 when viewed from the rear of the vehicle.

[0067] As shown in FIG. 8, the cover surface 61 extends in the vehicle width direction across the vehicle width direction intermediate portions of the pair of left and right rear side frame lowers 3B. 7 and 8, the cover member 60 described above is provided with a guide portion 62 that guides downward the underfloor traveling wind e1 that flows from the front to the rear of the vehicle below the silencer 10. That is, the cover member 60 is provided with a guide surface 63 that is located forward of the cover surface 61 serving as a shielding surface and that guides downward the underfloor traveling wind e1 that flows from the front to the rear of the vehicle below the silencer 10.

[0068] As shown in FIG. 8, the guide surface 63 extends in the vehicle width direction between the vertical wall portions on the inner sides in the vehicle width direction of the pair of left and right rear side frame lower sections 3B. In this way, the cover member 60 located between the rear bumper 4 and the silencer 10 extends in the vehicle width direction, overlapping in the vertical direction with at least the rear vertical wall 10b of the silencer 10 when viewed from the rear of the vehicle, and the cover member 60 is provided with a guide portion 62 that guides downward the underfloor traveling wind e1 that flows rearward below the silencer 10.

[0069] This reduces the visibility of the silencer 10 from the rear of the vehicle, improving its appearance, and also reduces the ingestion of underfloor running wind e1 behind the rear bumper 4 (see ingestion wind e4 indicated by the arrow in Figure 7), thereby improving the aerodynamic characteristics.

[0070] In detail, the cover member 60 overlaps at least the rear vertical wall 10b of the silencer 10 in the vertical direction when viewed from the rear of the vehicle, thereby preventing the silencer 10 from being seen from the rear of the vehicle and improving its appearance.

[0071] In addition, the cover member 60 is provided with a guide portion 62 that guides downward the underfloor traveling wind e1 that flows rearward under the silencer 10, and is configured to deflect the underfloor traveling wind e1 downward in order to suppress the underfloor traveling wind e1 from being drawn in behind the rear bumper 4 (see drawn-in wind e4), thereby improving aerodynamic characteristics.

[0072] As shown in Figures 9, 10, and 11, the above-mentioned cover member 60 has a front flange portion 64 extending from the upper end of the guide portion 62 toward the front of the vehicle, and a rising wall 65 rising upward from the front end of the front flange portion 64.

[0073] As shown in the figure, the cover member 60 has a rear flange portion 66 extending rearward from the upper end of the cover surface 61, and a rising wall 67 rising upward from the rear end of the rear flange portion 66.

[0074] A pair of left and right mounting portions 68 of the front flange portion 64 shown in Figure 9 are attached to the lower part of the retainer 17 (see Figure 8) using mounting members, and a pair of left and right mounting portions 69 of the rear flange portion 66 are attached to the lower part of the retainer 17 (see Figure 8) using mounting members.

[0075] As shown in FIG. 11, a blow-out hole 70 is provided at the lower rear portion of the guide portion 62, which guides downward and blows out the traveling wind (see blow-out wind e3 indicated by an arrow in FIG. 7) flowing rearward above the silencer 10. As shown in FIGS. 9 to 11, the blowout holes 70 are formed between the cover surface 61 and the guide surface 63. As shown in FIGS.

[0076] The above-mentioned blow-out hole 70 is located in the center in the vehicle width direction and is provided with a slit-shaped blow-out hole 71 (so-called slit-like opening) that is continuous over a predetermined range α in the vehicle width direction (see Figure 9), and a plurality of independent blow-out holes 72 (so-called square holes) with small opening areas that are located on the left and right outside the blow-out hole 71 in the vehicle width direction and spaced apart in the vehicle width direction.

[0077] In this embodiment, the predetermined range α is set to a length in the vehicle width direction that is approximately 30% of the distance between the vehicle width direction central portions of the left and right rear side frame lower sections 3B, but the length in the vehicle width direction of the slit-shaped outlet hole 71 is not limited to this. Also, although the outlet hole 72 is formed as a rectangular hole, it may be a circular hole.

[0078] The underfloor traveling wind e1 flowing rearward below the silencer 10 hits the guide portion 62, is guided downward by the guide portion 62, and then is separated and flows further rearward as separated wind e2, but by providing the above-mentioned blowout holes 70, the traveling wind (blowing wind e3) blown out from the blowout holes 70 pushes the separated wind e2 further downward. This further suppresses the entrainment of underfloor traveling wind behind the rear bumper 4 (entrained wind e4), thereby further improving the aerodynamic characteristics.

[0079] 8 and 9, by forming the outlet holes 70 in the shape of slits that are long in the vehicle width direction at the vehicle width center of the cover member 60, it is possible to sufficiently ensure the function of pushing down the underfloor traveling wind at the vehicle width center (see the separation wind e2 shown in FIG. 7) by the wind (i.e., blown wind e3) blown out from the outlet holes 70 that are slits that are long in the vehicle width direction. This configuration further reliably suppresses the underfloor traveling wind from being drawn in behind the rear bumper 4.

[0080] Furthermore, as shown in FIGS. 7 and 11, the guide surface 63 and the cover surface 61 are provided offset in the front-rear direction of the vehicle. Originally, the shielding function required of the cover surface 61, which is a shielding surface, and the guide function required of the guide surface 63 are different, but by offsetting the above-mentioned guide surface 63 and cover surface 61 in the fore-and-aft direction of the vehicle, the configuration is such that the functions required for each are secured.

[0081] 11, the cover surface 61 is formed to be inclined so that the lower portion thereof is positioned more forward of the vehicle, while the guide surface 63 is formed to be inclined so that the lower portion thereof is positioned more rearward of the vehicle. In this embodiment, as shown in the drawing, the cover surface 61 is formed to be inclined so that the lower portion thereof is positioned more forward of the vehicle at an inclination angle θ1 with respect to an imaginary vertical line (VER), and the inclination angle θ1 is set to about 15 degrees.

[0082] The guide surface 63 is formed in an inclined shape with an inclination angle θ2 relative to the imaginary vertical line (VER) so that the lower part is positioned rearward of the vehicle, and the inclination angle θ2 is set in the range of 15 degrees to 30 degrees. Note that the inclination angles θ1 and θ2 are not limited to these values.

[0083] As a result, the cover surface 61 and the guide surface 63 are configured to have inclined shapes that meet the requirements of the cover surface 61 and the guide surface 63, respectively. 10, a plurality of ribs 73 are formed across the entire width of the vehicle between the guide surface 63 and the cover surface 61, which are offset in the vehicle longitudinal direction, and connect the guide surface 63 and the cover surface 61 in the vehicle longitudinal direction. The thickness of each of these ribs 73 is thin so as not to obstruct the flow of the blown air e3. The ribs 73 are configured to ensure the rigidity of the area where the blowout holes 70 are formed.

[0084] Furthermore, the cover member 60 (shielding member) having the above-mentioned cover surface 61, guide portion 62, guide surface 63, flange portions 64, 66, rising walls 65, 67, mounting portions 68, 69, blowing holes 70, and ribs 73 can be integrally formed from synthetic resin. 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.

[0085] As described above, the vehicle lower body structure according to this embodiment is a vehicle lower body structure including the silencer 10 arranged horizontally so as to extend in the vehicle width direction in front of the lower part of the rear bumper 4, and is characterized in that a shielding member (see cover member 60) is provided between the rear bumper 4 and the silencer 10, and the shielding member (cover member 60) is arranged so as to extend in the vehicle width direction while overlapping in the vertical direction with at least the rear vertical wall 10b of the silencer 10 when viewed from the rear of the vehicle, and the shielding member (cover member 60) is provided with a guide portion 62 that guides downward the underfloor traveling wind e1 that flows rearward below the silencer 10 (see FIG. 7).

[0086] Such a vehicle lower body structure reduces visibility of the silencer 10 from the rear of the vehicle, improving the appearance, and also reduces the ingestion of wind from the vehicle's underfloor behind the rear bumper 4, improving the aerodynamic characteristics.

[0087] In detail, the shielding member (cover member 60) overlaps with at least the rear vertical wall 10b of the silencer 10 in the vertical direction when viewed from the rear of the vehicle, thereby preventing the silencer 10 from being seen from the rear of the vehicle, thereby improving the appearance.

[0088] In addition, the shielding member (cover member 60) is provided with a guide portion 62 that guides downward the underfloor traveling wind e1 that flows rearward under the silencer 10. Therefore, in order to suppress the underfloor traveling wind from being drawn in behind the rear bumper 4 (see drawn-in wind e4), the underfloor traveling wind (specifically, the separated wind e2) can be deflected downward, thereby improving the aerodynamic characteristics.

[0089] In addition, in the lower body structure of such a vehicle, the guide portion 62 is provided with an outlet hole 70 that guides downward and blows out the traveling wind (blowing wind e3) flowing rearward above the silencer 10 (see Figures 7 and 11).

[0090] According to such a vehicle lower body structure, the running wind (blowing wind e3) blown downward from the outlet hole 70 pushes the underfloor running wind (separating wind e2) downward, thereby further suppressing the entrainment of the underfloor running wind (entrained wind e4) behind the rear bumper 4 and further improving the aerodynamic characteristics.

[0091] Furthermore, in the underbody structure of such a vehicle, the shielding member (cover member 60) has a shielding surface (cover surface 61) that overlaps in the vertical direction with at least the rear vertical wall 10b of the silencer 10 when viewed from the rear of the vehicle, and a guide surface 63 that is located forward of the shielding surface (cover surface 61) and guides downward the underfloor traveling wind e1 that flows rearward below the silencer 10, and the guide surface 63 and the shielding surface (cover surface 61) are arranged offset in the fore-and-aft direction of the vehicle (see Figure 7).

[0092] Such a vehicle underbody structure has the following advantages: In other words, although the shielding function required of the shielding surface (cover surface 61) and the guide function required of the guide surface 63 are originally different, by offsetting the guide surface 63 and the shielding surface (cover surface 61) in the fore-and-aft direction of the vehicle, it is possible to ensure the functions that meet each requirement.

[0093] Furthermore, in the lower body structure of such a vehicle, the shielding surface (cover surface 61) is formed in an inclined shape that is positioned further forward of the vehicle as it goes downward, and the guide surface 63 is formed in an inclined shape that is positioned further rearward of the vehicle as it goes downward (see Figure 11). According to such a vehicle lower body structure, the shielding surface (cover surface 61) and the guide surface 63 can be formed in an inclined shape according to the requirements of each of the shielding surface (cover surface 61) and the guide surface 63.

[0094] In addition, in such a vehicle lower body structure, the blowout holes 70 are formed between the shielding surface (cover surface 61) and the guide surface 63 (see FIG. 11). According to such a vehicle lower body structure, the wind (blowing wind e3) blown out from the blowing hole 70 formed between the shielding surface (cover surface 61) and the guide surface 63 pushes the underfloor traveling wind (separating wind e2) downward, thereby suppressing the entrainment of the underfloor traveling wind (entrained wind e4) behind the rear bumper 4 and improving the aerodynamic characteristics.

[0095] In addition, in the lower body structure of such a vehicle, the blow-out hole 70 is formed in the vehicle width direction central portion of the shielding member (cover member 60) in the shape of a slit (see blow-out hole 71) that is long in the vehicle width direction (see Figure 9).

[0096] With this type of vehicle lower body structure, the function of pushing down the underfloor traveling wind (separation wind e2) in the center of the vehicle width direction by the wind (blowing wind e3) blown out from the slit-shaped outlet hole 71 that is long in the vehicle width direction can be sufficiently ensured, and the underfloor traveling wind can be more reliably suppressed from being drawn in behind the rear bumper 4 (drawn wind e4).

[0097] In the configuration of this invention and the correspondence with the above-mentioned embodiment, The shielding member of this invention corresponds to the cover member 60 of the embodiment, Similarly, The shielding surface corresponds to the cover surface 61, The present invention is not limited to the configurations of the above-described embodiments. [Industrial Applicability]

[0098] INDUSTRIAL APPLICABILITY As described above, the present invention is useful for a vehicle lower body structure having a silencer disposed transversely in front of a lower portion of a rear bumper so as to extend in the vehicle width direction. [Explanation of symbols]

[0099] 4...Rear bumper 10...Silencer 10b...Rear vertical wall 60...Cover member (shielding member) 61...Cover surface (shielding surface) ) 6 3...Guide surface 70...Blowout hole

Claims

1. A vehicle lower body structure including a silencer disposed transversely so as to extend in a vehicle width direction in front of a lower portion of a rear bumper, a shielding member is provided between the rear bumper and the silencer; The shielding member is provided to extend in the vehicle width direction, the shielding member includes a shielding surface that overlaps with at least a rear vertical wall of the silencer in a rear view of the vehicle, and a guide surface that is located forward of the shielding surface and guides downward an underfloor traveling wind that flows rearward below the silencer, The guide surface and the shielding surface are provided offset in the vehicle front-rear direction, Between the shielding surface and the guide surface, a blow-out hole is provided to guide downward the traveling wind flowing rearward through the upper part of the silencer and blow it out. The vehicle's underbody structure.

2. The guide surface is provided at the front edge of the blow-out hole so as to protrude downward from the periphery of the front edge, and the shielding surface is provided at the rear edge of the blow-out hole so as to protrude downward from the periphery of the rear edge. The vehicle underbody structure according to claim 1 .

3. The guide surface and the shielding surface are provided in a protruding shape so that their lower ends are at the same position. The vehicle underbody structure according to claim 2.

4. The height of the lower rear end position where the underfloor running wind flowing rearward through the lower part of the silencer separates rearward from the lower part of the silencer is defined as the silencer lower rear end height, the peripheral portion of the front edge portion and the peripheral portion of the rear edge portion are both located above a height of a rear end of the silencer lower portion, The guide surface and the shielding surface both protrude downward to a height corresponding to the height of the rear end of the lower part of the silencer. The vehicle underbody structure according to claim 3.

5. The shielding surface is formed in an inclined shape such that the lower portion thereof is positioned forward of the vehicle, and the guide surface is formed in an inclined shape such that the lower portion thereof is positioned rearward of the vehicle. The vehicle underbody structure according to any one of claims 1 to 4.

6. The blowout hole is formed in the shape of a slit that is long in the vehicle width direction at the center of the shielding member in the vehicle width direction. The vehicle underbody structure according to any one of claims 1 to 5.

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