Vehicle lower part structure

Abstract

To provide a vehicle lower part structure which inhibits occurence of noise by wind in a narrow band while preventing water from accumulating at the upper surface side of an absorber.SOLUTION: A vehicle lower part structure includes: a lower bumper 20; and an absorber 30 disposed at a rear side lower part of the lower bumper 20. The lower bumper 20 has inclined surface parts 24a, 24b which gradually incline rearward from a front part in a downward direction. At an upper surface part 31 of the absorber 30, a cylindrical rib structure comprising a plurality of vertical walls extending upward from an upper surface is provided. Through holes 39 are formed at a bottom part of the rib structure. A projection part 37 protruding downward and extending in a width direction is provided at a lower surface part 33 of the absorber 30. The through holes 39 are disposed at the front side in an intermediate part in the width direction of the projection part 37.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a vehicle undercarriage. [Background technology]

[0002] For example, a front bumper is disposed at the front of a vehicle. The front bumper is, for example, a member constituting a bumper face, and is a resin member having a design surface. For example, as disclosed in Patent Document 1, a structure is known in which an absorber is disposed on the lower side of the front of the vehicle, rear of the lower part of the front bumper. The absorbers are disposed, for example, side by side behind the lower part of the front bumper. The lower surface of the absorber is the outer surface of the lower part of the vehicle, and is the design surface.

[0003] The absorber has a function of converting impact energy into deformation energy and absorbing the impact by deforming in the longitudinal direction of the vehicle when an impact load such as a frontal collision acts on the front part of the vehicle. On the other hand, the absorber in the above example has, for example, a plurality of ribs to ensure a predetermined rigidity. The ribs protrude upward from the upper surface of the absorber and are formed, for example, in a lattice shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-176456 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned rib structure, there is a possibility that water may accumulate at the bottom of the lattice. Therefore, in accordance with the design criteria, it is necessary to form at least one drain hole at the bottom of the lattice. The drain hole penetrates the vehicle in the vertical direction, so it is possible to prevent water from accumulating in the lattice rib.

[0006] However, providing a drain hole penetrating in the vertical direction of the vehicle may cause a whistling noise. The whistling noise is generated, for example, when air flowing along the surface of the lower part of the front bumper flows below the drain hole. The whistling noise is so-called narrow-band wind noise, and since it is a sound that can be heard by passengers in the vehicle cabin, it may affect the quietness of the vehicle cabin. Therefore, the structure of the above example has room for improvement in order to suppress narrow-band wind noise while ensuring the rigidity of the absorber and suppressing water accumulation on the upper surface side of the absorber.

[0007] The present invention has been made to solve the above-mentioned problems, and its object is to provide a vehicle underbody structure that is capable of suppressing narrow-band wind noise under the vehicle while ensuring the rigidity of the absorber and preventing water from pooling on the upper surface of the absorber. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the vehicle understructure of the present invention is a vehicle understructure having a front bumper arranged at the front of the vehicle, and an absorber arranged along the lower part of the rear side of the front bumper, wherein the front bumper has an inclined shape that slopes toward the rear of the vehicle as it moves from the front of the front bumper toward the bottom of the vehicle, and the upper surface of the absorber is provided with a cylindrical rib structure composed of a plurality of vertical walls extending upward from the upper surface of the absorber, and a through hole is formed at the bottom of the rib structure that penetrates in the vertical direction of the vehicle, and the lower surface of the absorber is provided with a protrusion that protrudes downward of the vehicle and extends in the vehicle width direction, and the through hole is arranged on the front side of the vehicle at the vehicle width middle part of the protrusion. Effect of the Invention

[0009] According to the present invention, it is possible to ensure the rigidity of the absorber and prevent water from pooling on the upper surface side of the absorber, while suppressing narrow-band wind noise under the vehicle. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic perspective view of a portion of a vehicle having a vehicle underbody structure according to the present invention, as viewed from the front side of the vehicle. [Diagram 2] 2 is a perspective view of the vehicle underbody structure of FIG. 1 as viewed from below the vehicle. [Diagram 3] 3 is a bottom view of the lower bumper and the absorber in FIG. 2. [Figure 4] FIG. 4 is a perspective view of the lower bumper and the absorber shown in FIG. [Diagram 5] 4 is a schematic cross-sectional view showing a cross section taken along the line AA in FIG. 3. [Figure 6] FIG. 4 is a perspective view including a cross section taken along the line BB in FIG. [Figure 7] 4 is a schematic cross-sectional view showing a cross section taken along the line BB in FIG. 3. [Figure 8] 4 is a perspective view of the curved portion and the like in FIG. 3 as viewed from below and in front of the vehicle. [Figure 9] 4 is a perspective view of the absorber in FIG. 3 as viewed from below. FIG. [Figure 10] 4 is a perspective view of the absorber in FIG. 3 as viewed from above. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a vehicle underbody structure according to the present invention will be described with reference to the drawings (FIGS. 1 to 10). In the drawings, the direction of the arrow Fr indicates the front in the vehicle longitudinal direction. In the description of the embodiment, the "front (front end) and rear (rear end)" correspond to the front and rear in the vehicle longitudinal direction. Additionally, the arrows R and L indicate the right and left sides when an occupant looks forward of the vehicle. Additionally, the arrow U indicates the upward direction in the vehicle vertical direction.

[0012] The vehicle underbody structure of this embodiment is a structure for the lower portion of a bumper face configured at the front of the vehicle, as shown in Figures 1 and 2. The vehicle underbody structure has a front bumper 1 and an absorber 30. The front bumper 1 is a member disposed at the front of the vehicle, and has an inclined shape that inclines toward the rear of the vehicle as it moves from the front of the front bumper 1 toward the bottom of the vehicle. The absorber 30 is disposed along the lower portion on the rear side of the front bumper 1. The front bumper 1 and the absorber 30 will be described below.

[0013] First, a description will be given of the front bumper 1. The front bumper 1 of this embodiment has an upper bumper 10 and a lower bumper 20 which is a separate member from the upper bumper 10.

[0014] As shown in FIG. 1, the upper bumper 10 is formed such that the vehicle width direction intermediate portion protrudes toward the vehicle front with respect to the vehicle width direction outer portion. In this example, the upper bumper 10 has a front portion 11, a central lower surface portion 14, an outer curved portion 16, a lower curved portion 17, and an outer bottom surface portion 18. The front portion 11 is a portion facing the front of the vehicle and is disposed in the vehicle width direction intermediate portion of the upper bumper 10. The front portion 11 is provided with a front grill portion 12. The front grill portion 12 is a portion disposed in the vehicle width direction central portion of the upper bumper 10 and has an opening extending in the vehicle width direction. In addition, a plate attachment portion (not shown) to which, for example, a license plate is attached is provided in the vehicle width direction central portion at the lower portion of the front grill portion 12.

[0015] As shown in Fig. 1, the outer curved portion 16 is a portion formed so as to curve from the outer end of the front portion 11 in the vehicle width direction toward the rear of the vehicle as it moves outward in the vehicle width direction. In this example, the outer curved portion 16 is disposed on the outer side of the front grill portion 12 in the vehicle width direction, and the outer curved portion 16 is provided with a headlight mounting portion 16a and a fog lamp mounting portion 16b. The headlight mounting portion 16a and the fog lamp mounting portion 16b are disposed at intervals in the vertical direction of the vehicle. The headlight mounting portion 16a is disposed at intervals on both sides of the front grill portion 12 in the vehicle width direction. The fog lamp mounting portions 16b are disposed at intervals below the left and right headlight mounting portions 16a.

[0016] The lower curved portion 17 is disposed below the outer curved portion 16, and curves from the lower end of the outer curved portion 16 toward the rear of the vehicle and inward in the vehicle width direction as it moves downward. The central lower surface portion 14 is disposed at the lower end of the front portion 11, and has a lower surface facing downward of the vehicle, the lower surface extending in the vehicle width direction. In this example, the central lower surface portion 14 is disposed below the front grill portion 12 with a gap therebetween.

[0017] As shown in FIG. 1, an inclined lower surface portion 15 is provided on the outer side of the central lower surface portion 14 in the vehicle width direction, inclining downward and rearward from the outer end of the central lower surface portion 14 toward the outer side in the vehicle width direction. The inclined lower surface portion 15 is a portion of the lower part of the outer curved portion 16 that is disposed in the front part. The lower part of the inclined lower surface portion 15 is connected to the upper end of the front part of the lower curved portion 17. The outer bottom surface portion 18 is disposed under the lower curved portion 17, and is a portion that faces downward of the vehicle, and is curved toward the rear of the vehicle as it moves toward the outer side in the vehicle width direction. The outer curved portion 16, the lower curved portion 17, and the bottom surface portion are curved to reduce air resistance acting while the vehicle is traveling.

[0018] The central lower surface portion 14 is disposed above the lower end of the outer curved portion 16. That is, a concave portion 10a that is concave toward the upper side of the vehicle in a front view is formed in the lower part of the upper bumper 10. In this example, the concave portion 10a is formed by the central lower surface portion 14, the inclined lower surface portion 15, and the front end portion of the lower curved portion 17 (FIG. 1).

[0019] Next, the lower bumper 20 will be described. As shown in Fig. 1 to Fig. 4, the lower bumper 20 is a resin member extending in the vehicle width direction as a whole, and has a bumper center portion 21, a bumper outer inclined portion 27, and a lower grill portion 22. The lower bumper 20 is disposed in the lower portion of the upper bumper, inside the recessed portion 10a of the upper bumper 10 in a front view (Fig. 1).

[0020] The bumper central portion 21 is a portion located in the middle of the lower bumper 20 in the vehicle width direction, and has a central front end portion 21a, a central upper surface portion 21b, and a central lower surface portion 24. The central front end portion 21a is a portion located at the front end of the bumper central portion 21 of the lower bumper 20, extends in the vehicle width direction, and has an inclined surface that inclines toward the rear of the vehicle as it moves from the front end of the bumper central portion 21 toward the rear of the vehicle.

[0021] As shown in Figures 5 and 6, the central upper surface portion 21b is disposed on the upper portion of the bumper central portion 21, extends in the vehicle width direction, and is inclined upward from the upper end of the central front end portion 21a toward the rear of the vehicle. In this example, the inclination angle of the central upper surface portion 21b (angle α1 in Figure 5) is set to be smaller than the inclination angle of the central front end portion 21a. The inclination angle here indicates an acute angle intersecting with the horizontal line L1 shown in Figure 5. For example, the inclination angle of the central upper surface portion 21b is an acute angle formed on the vehicle rear side by the inclination direction of the central upper surface portion 21b and the horizontal line L1.

[0022] As shown in Figs. 3 to 6, the central lower surface portion 24 is disposed at the lower portion of the bumper central portion 21 and extends in the vehicle width direction. The central lower surface portion 24 of the lower bumper 20 has a first central inclined surface portion 24a and a second central inclined surface portion 24b. The first central inclined surface portion 24a is an inclined surface extending in the vehicle width direction, and is inclined downward from the lower end of the central front end portion 21a toward the rear of the vehicle. The second central inclined surface portion 24b is an inclined surface extending in the vehicle width direction, and is inclined downward from the rear end of the first central inclined surface portion 24a toward the rear of the vehicle. The rear end portion of the second central inclined surface portion 24b extends linearly in the vehicle width direction. A connection portion with the absorber 30 is provided at the rear end portion. The connection portion will be described later.

[0023] The inclination angle of the first central inclined surface portion 24a (angle α2 in FIG. 5) is set to be larger than the inclination angle of the second central inclined surface portion 24b. The inclination angle here indicates an acute angle intersecting with the horizontal line L2 shown in FIG. For example, the inclination angle of the first central inclined surface portion 24a is an acute angle formed on the vehicle front side by the inclination direction of the first central inclined surface portion 24a and the horizontal line L2.

[0024] In this embodiment, the central lower surface portion 24 of the lower bumper 20 is composed of the first central inclined surface portion 24a and the second central inclined surface portion 24b, but is not limited thereto. For example, the central lower surface portion 24 may be curved downward from the lower end of the central front end portion 21a toward the rear of the vehicle. In this case, the curvature of the curve may be changed at a predetermined position to form a predetermined air flow. Here, the predetermined position may be, for example, a position corresponding to the rear end of the first central inclined surface portion 24a.

[0025] As shown in Figs. 3 and 4, the bumper outer inclined portion 27 is inclined toward the rear of the vehicle as it moves from the vehicle width direction middle portion to the outside in the vehicle width direction. In this example, it is inclined toward the rear of the vehicle as it moves in the vehicle width direction from the vehicle width direction outer portion of the bumper center portion 21. Although detailed explanation by illustration is omitted, the bumper outer inclined portion 27 has an outer front end portion and an outer lower surface portion. Although not illustrated, the outer upper surface portion may be formed in the same manner as the central upper surface portion 21b. The outer front end portion is provided continuously from the vehicle width direction outer side of the central front end portion 21a to the vehicle width direction outer side, and may have an inclined surface similar to that of the central front end portion 21a.

[0026] The outer lower surface portion has a first outer inclined surface portion provided contiguous to the outer side of the first central inclined surface portion 24a of the central lower surface portion 24, and a second outer inclined surface portion provided contiguous to the outer side of the second central inclined surface portion 24b. It is preferable that the first outer inclined surface portion has a similar inclination angle to the first central inclined surface portion 24a, and the second outer inclined surface portion has a similar inclination angle to the first central inclined surface portion 24a.

[0027] In this example, the outer end of the first outer inclined surface portion in the vehicle width direction is connected to a front portion of the lower curved portion 17 of the upper bumper 10. The first outer inclined surface portion and the lower curved portion 17 may be arranged to abut against each other, or may be arranged with a gap therebetween. The outer end of the second outer inclined surface portion in the vehicle width direction is connected to a front portion of the outer bottom surface portion 18 of the upper bumper 10. The second outer inclined surface portion and the outer bottom surface portion 18 may also be arranged to abut against each other, or may be arranged with a gap therebetween.

[0028] 1, the lower grill section 22 is provided on the upper surface section 31 of the bumper central section 21, and has a frame shape with an opening penetrating in the vehicle front-rear direction. The opening of the lower grill section 22 is provided with a plurality of vertical ribs 22a extending so as to connect the upper and lower ends of the opening. The vertical ribs 22a are arranged at intervals from one another in the vehicle width direction.

[0029] The vehicle width direction intermediate portion of the upper part of the lower grill portion 22 constitutes the upper opening edge of the opening, extends in the vehicle width direction, and is disposed opposite the central lower surface portion 14 of the upper bumper 10. Although not shown in detail, the vehicle width direction outer portion of the upper part of the lower grill portion 22 is preferably inclined along the inclined lower surface portion 15 of the upper bumper 10. The lower part of the lower grill portion 22 is integrally connected to the upper surface portion 31 of the bumper central portion 21.

[0030] As shown in Fig. 1, outer front wall portions 23 are provided on both sides of the vehicle width direction outer portion on the front side of the lower grill portion 22. The left and right outer front wall portions 23 are arranged at an interval from each other on both sides of the opening of the lower grill portion 22. The outer front wall portions 23 have a wall surface that protrudes upward from the outer front end portion of the bumper outer inclined portion 27 on the vehicle width direction outer side of the central upper surface portion 21b of the bumper central portion 21. The inner end of the outer front wall portion 23 in the vehicle width direction forms an opening edge on the outer side in the vehicle width direction of the opening of the lower grill portion 22.

[0031] Next, the absorber 30 of this embodiment will be described. As shown in Figs. 1 and 2, the absorber 30 is disposed along the rear lower portion of the lower bumper 20 of the front bumper 1. The absorber 30 is a resin member extending in the vehicle width direction as a whole, and has an upper surface portion 31 and a lower surface portion 33. The middle portion in the vehicle width direction of the front end of the absorber 30 extends linearly in the vehicle width direction. The outer portion in the vehicle width direction of the front end is inclined toward the rear of the vehicle as it moves outward in the vehicle width direction. The inclination of the outer portion may be inclined along the inclination direction of the bumper outer inclined portion 27 of the lower bumper 20.

[0032] The upper surface portion 31 is provided with a cylindrical rib structure 32 composed of multiple vertical walls extending upward from the upper surface of the absorber 30, and a through hole 39 is formed in the bottom of the rib structure 32, penetrating in the vertical direction of the vehicle. The rib structure 32 has multiple box-shaped bodies in a substantially rectangular parallelepiped shape, for example, as shown in Figs. 6 and 10. These are arranged side by side in the vehicle width direction and the vehicle front-rear direction while being in contact with each other. That is, the rib structure 32 of this embodiment is configured in a lattice shape. It is preferable that a through hole 39 for draining water is formed in the bottom of all of the rib structures 32 configured in a lattice shape.

[0033] 5 to 7, the front part of the upper surface portion 31 is disposed above the second central inclined surface portion 24b of the lower bumper 20 with a gap therebetween. In this example, the front end of the upper surface portion 31 is disposed on the vehicle rear side of the first central inclined surface portion 24a with a gap therebetween. Although detailed explanation using drawings is omitted, the upper surface portion 31 is attached to a highly rigid vehicle body structure formed of, for example, a metal material.

[0034] The lower surface portion 33 is provided with a protrusion 37 that is disposed on the vehicle front side of the through hole 39 and protrudes downward. As shown in Figs. 3 and 4, the lower surface portion 33 has a lower surface facing the vehicle downward. The surface of the lower surface is a smooth surface with small surface roughness. A plurality of circular through holes 39 for draining water are formed on the lower surface. In this manner, by forming the through holes 39 for draining water, even if water enters the lattice-shaped rib structure 32 formed on the upper surface portion 31, the water inside the rib structure 32 is discharged from the through holes 39 for draining water to the outside of the vehicle. Therefore, in this embodiment, it is possible to suppress water from accumulating on the upper surface portion 31 of the absorber 30.

[0035] In this embodiment, the diameter of the through hole 39 is preferably about 8.5 mm. Therefore, the bottom of the rib structure 32 is preferably rectangular, with one side longer than 8.5 mm.

[0036] As shown in FIG. 9, the lower surface portion 33 has a front-stage lower surface portion 34 and a rear-stage lower surface portion 35. The front-stage lower surface portion 34 includes the front end of the absorber 30 and has a surface extending from the front end toward the rear of the vehicle. The rear-stage lower surface portion 35 is disposed rearward and below the front-stage lower surface portion 34. As shown in FIGS. 5 to 7 and 9, the front-stage lower surface portion 34 is provided with a groove portion 34a, which extends in the vehicle width direction. The groove portion 34a has a rectangular cross-sectional shape. The bottom of the groove portion 34a has a bottom surface facing the vehicle downward. For example, by providing the groove portion 34a, it is possible to set it as a starting point for the absorber 30 to be crushed in the vehicle front-rear direction.

[0037] In this embodiment, a lower rib structure 33A is provided on the vehicle width direction outer side of the lower surface portion 33. The lower rib structure 33A has a box shape similar to the rib structure 32 provided on the upper surface portion 31, and is open downward.

[0038] As shown in Figures 8 and 9, a curved portion 36 is provided between the front-stage lower surface portion 34 and the rear-stage lower surface portion 35. The curved portion 36 curves toward the rear of the vehicle as it approaches the bottom of the vehicle, and the curved portion 36 is smoothly connected to the rear-stage lower surface portion 35. The protrusion 37 is provided at the rear of the curved portion 36. The relationship between the curved portion 36 and the protrusion 37 will be described later.

[0039] The protrusion 37 in this embodiment is disposed in the middle of the lower surface portion 33 (in this example, the rear-stage lower surface portion 35) in the vehicle width direction where the through holes 39 for draining water are densely arranged. Moreover, the protrusion 37 is disposed in the middle of the lower surface portion 33 in the vehicle front-rear direction. The protrusion 37 in this example is disposed in the front portion of the rear-stage lower surface portion 35. The front portion of the front-stage lower surface portion 34 is disposed above the boundary between the first central inclined surface portion 24a and the second central inclined surface portion 24b with a gap therebetween. Moreover, the front-stage lower surface portion 34 is disposed opposite the second central inclined surface portion 24b.

[0040] As shown in Figs. 3 to 5 and 9, the protrusion 37 extends in the vehicle width direction while protruding downward from the vehicle. In this example, the cross section of the protrusion 37 is substantially square, and the protrusion 37 is formed in a rectangular parallelepiped shape as a whole. In this example, the vertical length of the protrusion 37 is preferably 0.5 mm or more. The protrusion 37 is disposed on the vehicle rear side with a gap therebetween from the lower end of the second central inclined surface portion 24b of the lower bumper 20. The distance between the protrusion 37 and the front end of the opening edge of the through hole 39 in the vehicle longitudinal direction is preferably within 5 mm. More preferably, the distance is set to about 2 mm.

[0041] The absorber 30 is made of a resin material and needs to have a certain level of rigidity. Therefore, by arranging the lattice-like rib structure 32 so as to be densely packed, it is possible to ensure the required level of rigidity.

[0042] In addition, at least one through hole 39 for draining water is formed in the wall (enclosure wall) surrounding the rib structure 32. By providing the through hole 39 for draining water, air flowing below the lower bumper 20 generates a vortex when it separates, and the air flowing below the absorber 30 located behind the lower bumper 20 hits the opening edge (edge ​​portion) of the through hole 39 for draining water, which may generate a pressure wave and a whistling noise.

[0043] In contrast, in this embodiment, since the protrusion 37 is provided in front of the through hole 39, the separated vortex flow in the air flowing on the lower surface side of the absorber 30 can be prevented from hitting the opening edge of the through hole 39. As a result, in this embodiment, even if the absorber 30 has the through hole 39 for draining water, it is possible to suppress the generation of the whistling sound. That is, with the above-mentioned configuration, it is possible to ensure the rigidity of the absorber 30, prevent water from pooling on the upper surface side of the absorber 30, and suppress narrow-band wind noise (whistling sound) in the lower part of the vehicle. Note that if the lower bumper 20 is designed so that the portion corresponding to the first central inclined surface portion 24a bulges downward, the possibility of the generation of the whistling sound is reduced, but in the case of a shape such as the first central inclined surface portion 24a and the second central inclined surface portion 24b, providing the protrusion 37 on the absorber 30 is effective in suppressing the whistling sound.

[0044] In this embodiment, as shown in Figures 3 to 5, 8 and 9, a plurality of through holes 39 are arranged at intervals in the vehicle width direction along the vehicle width direction intermediate portion of the protrusion 37. That is, a plurality of through holes 39 are arranged on the rear side of one protrusion 37 extending in the vehicle width direction. This makes it possible to more effectively prevent the vortex from colliding with the opening edge of the through hole 39.

[0045] As described above, the protrusion 37 has a substantially square cross-sectional shape. Therefore, the rear portion of the protrusion 37 has a rear surface facing the rear of the vehicle, and the rear surface extends from the lower surface of the absorber 30 downward toward the vehicle. As a result, the protrusion 37 is formed to cover the front of the through hole 39 in the vehicle width direction, so that it is possible to reliably prevent vortexes generated by separation from hitting the opening edge of the through hole 39. As a result, it is possible to more effectively suppress the generation of whistling noise.

[0046] In this embodiment, the rear surface of the protrusion 37 is a plane extending in the vertical direction, but is not limited to this. For example, the rear surface may be an inclined surface that inclines toward the rear of the vehicle as it approaches the bottom of the vehicle, so that the angle formed by the rear surface of the protrusion 37 and the rear-stage lower surface portion 35 located on the rear side of the rear surface becomes an acute angle. In this embodiment, the front surface of the protrusion 37 is also a plane extending in the vertical direction, but is not limited to this. For example, the rear surface may be inclined toward the rear of the vehicle as it approaches the bottom of the vehicle.

[0047] In addition, the protrusion 37 in this embodiment is formed in a rectangular parallelepiped shape extending in the vehicle width direction, but is not limited thereto. The cross-sectional shape of the protrusion 37 is a square, but the cross-sectional shape may be a rectangle with the vehicle vertical direction as the longitudinal direction. Furthermore, considering the inclination of the front and rear surfaces of the protrusion 37, the cross-sectional shape of the protrusion 37 may be, for example, a parallelogram inclined backward as it goes downward, a triangle with the front and rear surfaces inclined backward, a right triangle with the front surface inclined backward, etc.

[0048] In this embodiment, as described above, the lower bumper 20 has the bumper outer inclined portion 27 that inclines toward the rear of the vehicle from the middle portion in the vehicle width direction toward the outside in the vehicle width direction. The bumper outer inclined portion 27 is preferably arranged symmetrically (bilaterally symmetrically) with respect to a vehicle front-rear line passing through the center in the vehicle width direction. In addition, the protrusion 37 in this embodiment extends in the vehicle width direction so as to straddle the center in the vehicle width direction.

[0049] In addition, the absorber 30 and the lower bumper 20 are symmetrical in design at the center in the vehicle width direction, and the curved portion 36 extends in the vehicle width direction at the center in the vehicle width direction. Furthermore, a plurality of through holes 39 are arranged on the rear side of the curved portion 36. That is, the longitudinal direction of the curved portion 36 and the arrangement direction of the through holes 39 are arranged parallel to each other. If the protrusion 37 is not provided, the air flowing on the lower surface side of the lower bumper 20 is likely to hit the opening edge of each through hole 39 through the curved portion 36. As a result, the volume of the whistling sound may increase. In contrast, in this embodiment, the protrusion 37 is provided on the rear part of the curved portion 36 in front of the rear lower surface portion 35, so that it is possible to suppress the air flowing from the front of the vehicle from being blown against the opening edge of the through hole 39, and the whistling sound can be more effectively reduced.

[0050] 3 and 4, the outer portion of the absorber 30 in the vehicle width direction is curved toward the rear of the vehicle as it moves outward in the vehicle width direction so as to correspond to the bumper outer inclined portion 27. This allows the air flowing through the outer portion of the absorber 30 to flow outward in the vehicle width direction. Although not shown in detail, the middle portion of the absorber 30 in the vehicle width direction faces the outside of the vehicle, but the outer portion of the absorber 30 in the vehicle width direction is configured to be less likely to generate a whistling sound than the portion exposed to the outside, since other panels and the like are arranged on the underside of the absorber 30.

[0051] In this embodiment, a protrusion 37 is provided in the center in the vehicle width direction, where air easily flows through the absorber 30 while the vehicle is running, to reduce the occurrence of whistling noise.

[0052] 8 and 9, in this embodiment, the lower surface portion 33 of the absorber 30 is provided with a curved portion 36 that curves upward on the vehicle as it approaches the front of the vehicle, and the protrusion 37 is provided on the curved portion 36. In detail, as described above, the curved portion 36 is provided in front of the rear lower surface portion 35, and the protrusion 37 is disposed at the rear of the curved portion 36 (FIG. 5).

[0053] Also, the lower surface of the absorber 30 located on the rear side of the curved portion 36 may be disposed along an imaginary inclined line L3 that inclines upward toward the front of the vehicle, as shown in Fig. 5. Also, a part of the lower surface of the front bumper 1 may be disposed along the imaginary inclined line L3. In this embodiment, the lower surface of the rear stage lower surface portion 35 located on the rear side of the curved portion 36 is disposed along the imaginary inclined line L3. Furthermore, the imaginary inclined line L3 extends along the inclination direction of the second central inclined surface portion 24b.

[0054] Providing the protrusions 37 on the curved portion 36 improves the rigidity of the rear-stage lower surface portion 35 of the absorber 30. Also, by locating the lower surface of the rear-stage lower surface portion 35 on the imaginary inclined line L3 extending along the inclination direction of the second central inclined surface portion 24b, it is possible to suppress an increase in the air resistance coefficient CD value. Here, the CD value is an abbreviation for "Coefficient of Drag" and indicates the drag (resistance) coefficient.

[0055] In addition, since the rear part of the rear inclined surface portion can be positioned lower than the lower end of the protrusion 37, it is possible to prevent the protrusion 37 from being scraped even if it scrapes against the underside of the vehicle when going up a steep slope.

[0056] Next, a connection between the lower bumper 20 and the absorber 30 in this embodiment will be described. In this embodiment, a leg 25 protruding from the rear end of the lower bumper 20 (front bumper 1) in the vehicle width direction intermediate portion is provided at the rear end to connect to the absorber 30, and a recess 38 recessed upward is provided on the underside of a curved portion 36, and the leg 25 is disposed inside the recess 38 and fixed to the bottom of the recess 38 at a position above the rear end of the vehicle.

[0057] As shown in Figs. 3 to 5 and 9, the two legs 25 are arranged at a distance from each other at the rear of the bumper central portion 21, and one leg 25 is arranged at the rear of each of the bumper outer inclined portions 27 on both sides. Therefore, the absorber 30 has a total of four legs 25. For example, the leg 25 of the bumper central portion 21 protrudes toward the rear of the vehicle from the rear end of the second central inclined surface portion 24b. The leg 25 has, for example, a horizontal plane 25a and a vertical wall 25b provided on the side of the plane 25a, and the horizontal plane is provided with a hole 25c through which a clip or the like can be inserted. The other legs 25 are formed in the same manner.

[0058] The recess 38 is provided in the front part of the curved part 36, and the bottom of the recess 38 is preferably formed so as to be continuous with the front-stage lower surface part 34. In addition, the two recesses 38 corresponding to the leg parts 25 provided in the bumper central part 21 are arranged on the outer side of the protrusion 37 in the vehicle width direction, and the protrusion 37 is arranged between the two recesses 38. The leg parts 25 provided in the bumper outer inclined part 27 are provided on the outer side of the curved part 36 in the vehicle width direction. With the flat surface of the leg parts 25 abutting against the bottom of the recess 38, the recess 38 and the leg parts 25 are connected by a clip or the like. The bottom of the recess 38 is provided with a hole 38c into which a clip or the like can be inserted (FIG. 7).

[0059] Since the connection between the recess 38 and the leg 25 is located above the rear end of the lower surface of the lower bumper 20, air is not impeded from flowing along, for example, the first central inclined surface portion 24a and the second central inclined surface portion 24b of the lower bumper 20. As a result, the influence on the CD value is suppressed. In addition, since the air is effectively blown onto the protrusion 37, the air is prevented from hitting the opening edge of the through hole 39, and the generation of a whistling sound can be suppressed.

[0060] The description of the present embodiment is merely an example for explaining the present invention, and does not limit the invention described in the claims. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims.

[0061] In this embodiment, a plurality of through holes 39 are arranged at the rear of one protrusion 37, but this is not limited thereto. For example, one through hole 39 may be arranged at the rear of one protrusion 37. Also, a plurality of protrusions 37 may be provided. In this case, it is preferable to arrange one or a plurality of through holes 39 at the rear of each protrusion 37.

[0062] In addition, the rib structure 32 in this embodiment has a rectangular box shape, but is not limited to this. For example, it may have a hexagonal prism shape such as a honeycomb structure. In order to ensure the rigidity of the absorber 30, it is preferable that the rib structure 32 is arranged without any gaps. [Explanation of symbols]

[0063] 1 Front bumper 10 Upper Bumper 10a Concave part 11 Front section 12 Front grill section 12a Plate mounting part 14 Lower center part 15 Slanted lower surface section 16 Outer curve 16a Headlight mounting part 16b Fog lamp mounting part 17 Lower curved part 18 Outer bottom part 20 Lower bumper 21 Center of bumper 21a Center front end 21b Center top section 22 Lower grill section 22a Vertical rib 23 Front outer wall 24 Lower center part 24a 1st central slope section 24b 2nd central slope section 25 Legs 25a plane 25b vertical wall 25c Hole 27. Outer bumper slope 30 Absorber 31 Top part 32 リブstructure 33 Lower face 33A Lower side rib structure 34 Anterior lower face 35 Posterior lower face 36 Bay Qubu 37 protrusion 38 recess 38c Hole 39 Through hole

Claims

1. A vehicle underbody structure having a front bumper disposed at a front portion of a vehicle and an absorber disposed along a rear lower portion of the front bumper, the front bumper has an inclined shape inclined toward the rear of the vehicle as it moves from a front portion of the front bumper toward a lower portion of the vehicle, a cylindrical rib structure formed of a plurality of vertical walls extending upward from the upper surface of the absorber is provided on an upper surface of the absorber, and a through hole penetrating in a vehicle up-down direction is formed in a bottom portion of the rib structure, A protrusion protruding downward from the vehicle and extending in the vehicle width direction is provided on the lower surface of the absorber, The through hole is disposed on a vehicle front side in a vehicle width direction intermediate portion of the protrusion.

2. 2. The vehicle underbody structure according to claim 1, wherein a plurality of the through holes are arranged at intervals in the vehicle width direction along a middle portion of the protrusion in the vehicle width direction.

3. 2. The vehicle underbody structure according to claim 1, wherein the plurality of rib structures are arranged in a lattice pattern in the vehicle width direction and the vehicle front-rear direction.

4. 2. The vehicle underbody structure according to claim 1, wherein the protrusion has a rear surface facing toward the rear of the vehicle, the rear surface protruding downward from the lower surface of the absorber.

5. the front bumper has a bumper outer inclined portion inclined toward the rear of the vehicle from a vehicle width direction middle portion toward an outer side in the vehicle width direction, The vehicle underbody structure according to claim 1 , wherein the protrusion extends in a vehicle width direction so as to straddle a center of the vehicle in the vehicle width direction.

6. a lower surface portion of the absorber having a curved portion that curves upwardly toward the vehicle front and upwardly toward the vehicle front, and the protrusion portion is provided on the curved portion, a lower surface portion of the absorber located on the rear side of the curved portion is inclined along an imaginary inclination line that inclines upward toward the front of the vehicle, 2. The vehicle underbody structure according to claim 1, wherein a portion of the lower surface of the front bumper is disposed along the imaginary inclined line.

7. a leg portion protruding from a rear end of the front bumper in a vehicle width direction intermediate portion toward the rear of the vehicle; The curved portion has a lower surface provided with a recess that is recessed upward, 2. The vehicle underbody structure according to claim 1, wherein the leg portion is disposed inside the recess and fixed to a bottom of the recess above the rear end of the front bumper.

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