Vehicle undercarriage

Abstract

The objective is to provide a vehicle undercarriage structure that can prevent damage to the underbody cover due to road surface interference. [Solution] The vehicle understructure includes an under cover 4 that covers the bottom surface of the vehicle body 1 in front of a pair of front wheels 2 and in the area between the pair of front wheels 2. The under cover 4 has a movable panel 11 that is movable in the vertical direction, a fixed frame 12 positioned above the movable panel 11 and fixed to the bottom surface of the vehicle body 1, and a deformable deformable member 13 that connects at least the front end 11c of the movable panel 11 to the fixed frame 12. The deformable member 13 is made of a softer material than the movable panel 11 and deforms when the movable panel 11 comes into contact with the road surface. The deformable member 12 has a front portion 13a and a pair of side portions 13b that extend to the rear of the vehicle from both ends of the front portion 13a. A recess 14 is formed in the corner portion 13c that is recessed inward from the corner portion 13c.

Description

TECHNICAL FIELD

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

BACKGROUND ART

[0002] Conventionally, various vehicle lower structures provided with members such as an undercover on the lower side of the front portion of the vehicle body have been proposed in order to control the air flow flowing on the lower side of the vehicle body during vehicle travel. For example, Patent Document 1 discloses a vehicle provided with an undercover that descends during high-speed travel of the vehicle. In this vehicle, the negative pressure at the bottom of the vehicle body is increased by the bottom surface of the undercover that descends during high-speed travel, so that the adhesion of the vehicle body to the road surface is improved and the stability during high-speed travel is enhanced.

[0003] Further, Patent Document 2 discloses a vehicle provided with a movable tire cover that descends forward of a tire during high-speed travel of the vehicle. This movable tire cover prevents wind from hitting the tire during high-speed travel.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In both of the two structures described above, when the vehicle is traveling with a member such as an undercover on the lower front side of the vehicle body lowered to a lower position near the road surface, if an obstacle such as a block protruding from the road surface or a large step is encountered, the undercover may interfere with the obstacle or the step. In that case, the undercover may be damaged due to interference with the obstacle or step on the road surface.

[0006] In particular, the corners at both ends of the front of the underbody cover (i.e., the corners formed by the front and side sections of the underbody cover) are subjected to the greatest load during a road collision, so damage to these corners is a particular concern.

[0007] This invention has been made in view of the circumstances described above, and aims to provide a vehicle undercarriage structure that can prevent damage to the underbody cover due to road surface interference. [Means for solving the problem]

[0008] To solve the aforementioned problems, the vehicle understructure of the present invention includes an under cover that covers the bottom surface of the vehicle body in front of a pair of front wheels and in the area between the pair of front wheels, the under cover having a movable panel that is movable in the vertical direction, a fixed frame positioned above the movable panel and fixed to the bottom surface of the vehicle body, and a deformable member that connects the movable panel and the fixed frame, the deformable member being made of a softer material than the movable panel and deforming when the movable panel comes into contact with the road surface, the deformable member having a front portion extending in the vehicle width direction on the front side of the under cover and a pair of side portions extending to the rear of the vehicle from both ends of the front portion, and a recess formed inward at the corner formed by the front portion and the side portions of the deformable member.

[0009] With this configuration, when the movable panel comes into contact with the road surface, the movable panel lifts up. At this time, the corners at both ends of the front part of the deformable member deform smoothly, bending inward at the corners with the recesses as the bending starting point, making it easier for the movable panel to lift up with a small load. Therefore, it is possible to reliably reduce the rigidity of the corners at both ends of the front end of the under cover, where the load is greatest when the under cover comes into contact with the road surface. As a result, it becomes possible to prevent damage to the under cover when the under cover comes into contact with the road surface.

[0010] In the above-described underbody structure of the vehicle, it is preferable that the recess has a horizontal portion extending horizontally toward the rear of the vehicle and toward the inward side of the corner, and a vertical wall portion extending downward from the end of the horizontal portion that is on the inward side of the corner.

[0011] With this configuration, when the movable panel interferes with the road surface, the horizontal and vertical wall portions that make up the recess at the corner of the deformable member fold smoothly as the movable panel rises. As a result, the deformable member deforms more smoothly toward the inside of the corner, improving the effectiveness of preventing damage to the under cover.

[0012] Furthermore, since the horizontal portion of the recess extends towards the rear of the vehicle, it is possible to rectify the airflow during vehicle operation, thereby suppressing the generation of turbulence in the recess.

[0013] As a result, it is possible to achieve both improved breakability at the corners of the deformable member and enhanced aerodynamic performance.

[0014] In the above-described vehicle understructure, it is preferable that the inner end of the corner of the horizontal section is composed of a curved surface with a larger radius of curvature than the curved surface of the outer end of the corner.

[0015] This configuration allows for a larger horizontal area, increasing the portion extending towards the rear of the vehicle, which in turn allows air to flow more smoothly towards the rear. As a result, aerodynamic performance is further improved.

[0016] In the above-described vehicle understructure, the horizontal portion preferably has a triangular shape when viewed from below, and the horizontal portion preferably has a pair of slanted sides that extend inward in the vehicle rearward and vehicle width direction, respectively, forming an obtuse angle, and a base portion that extends outward in the vehicle width direction as it approaches the vehicle rearward.

[0017] According to such a configuration, the horizontal portion of the recess forms the triangular shape as described above, resulting in a simple shape. Therefore, it becomes easy to manufacture the undercover that achieves both the ease of folding at the corner portion of the deformable member and the improvement of aerodynamic performance, and the productivity of the undercover is enhanced. Effects of the Invention

[0018] As described above, according to the vehicle lower structure of the present invention, damage to the undercover due to road surface interference can be prevented. Brief Description of the Drawings

[0019] [Figure 1] This is a perspective view showing the main part of the vehicle lower structure according to the embodiment of the present invention, with the undercover and its peripheral portion viewed from the diagonally front left lower side. [Figure 2] This is an enlarged perspective view of the undercover in Fig. 1 viewed from the front right lower side. [Figure 3] This is a bottom view of the left portion of the undercover in Fig. 1. [Figure 4] This is a side view of the front portion of the left side surface of the undercover in Fig. 1. [Figure 5] This is a perspective view of the right half of the undercover in Fig. 1 viewed from the diagonally right lower side. [Figure 6] This is a bottom view of the recess formed at the corner portion of the deformable member in Fig. 3 and its peripheral portion. [Figure 7] This is a sectional view taken along line VII-VII in Fig. 6. [Figure 8] This is an enlarged perspective view of the recess in Fig. 6 and its peripheral portion viewed from the rear lower side and the inner side in the vehicle width direction. [Figure 9] This is a sectional view taken along line IX-IX in Fig. 5. [Figure 10] This is a sectional view taken along line X-X in Fig. 5. [Figure 11] This is a front view of the front left half of the vehicle body in Fig. 1. [Figure 12] This is a sectional view taken along line XII-XII in Fig. 5. Modes for Carrying Out the Invention

[0020] Hereinafter, a vehicle understructure according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0021] Figure 1 discloses a vehicle understructure equipped with an under cover 4 as an embodiment of the vehicle understructure of the present invention.

[0022] Specifically, the vehicle understructure shown in Figure 1 includes an under cover 4 that is movable in the vertical direction Z and covers the bottom surface of the vehicle body 1 in the area between the pair of front wheels 2, in front of the pair of front wheels 2 X1. As shown in Figures 1 and 11-12, the under cover 4 is positioned on the bottom surface of the vehicle body 1 in the area from near the front end of the bumper 3 to the front end of the front wheels 2.

[0023] Furthermore, in the vehicle understructure of this embodiment, as shown in Figure 1, a floor panel 5 covering the bottom surface of the vehicle body 1 is positioned X2 to the rear of the vehicle from the under cover 4. In addition, a pair of side under covers 6 are positioned on both sides of the under cover 4 in the vehicle width direction Y. Note that these floor panels 5 and side under covers 6 are not essential components in this invention and may be replaced with other members.

[0024] The following provides a more detailed explanation of the specific structure of Undercover 4.

[0025] As shown in Figures 2 to 12, the under cover 4 includes a movable panel 11 that is movable in the vertical direction Z, a fixed frame 12 positioned above the movable panel 11 and fixed to the bottom surface of the vehicle body 1, and a deformable member 13 that connects at least the front end 11c of the movable panel 11 (in this embodiment, the area A excluding the rear end 11d at both side ends 11e (see Figure 5)) and the fixed frame 12.

[0026] First, we will describe the deformable member 13 having a recess 14, which is a key feature of the vehicle understructure of this embodiment.

[0027] (Explanation of the deformable member 13) The deformable member 13 is made of a material softer than the movable panel 11, and is made of a resin material that is more easily deformed than polypropylene, such as an elastomer. As shown in Figure 12, the deformable member 13 is configured to deform when the movable panel 11 comes into contact with the road surface, thereby enabling the movable panel 11 to move upward. Specifically, the deformable member 13 is made of a film-like body made of an easily deformable elastomer.

[0028] Since the deformable member 13 is made of a soft, membrane-like material, it connects the movable panel 11 and the fixed frame 12, and also seals the gap between the movable panel 11 and the fixed frame 12, preventing air and water from entering the inside of the under cover 4.

[0029] In this embodiment, as shown in Figures 2 to 8, the deformable member 13, which is made of a film-like material, has recesses 14 at both ends in the vehicle width direction Y of the front portion 4a of the under cover 4, so as to be the starting points for deformation of the deformable member 13.

[0030] As shown in Figures 2-8, the deformable member 13 specifically has a front portion 13a extending in the vehicle width direction Y on the front side of the under cover 4, and a pair of side portions 13b extending from both ends of the front portion 13a toward the rear X2 of the vehicle.

[0031] A recess 14 is formed in the corner 13c of the deformable member 13, which is recessed inward D2 (see Figure 6) of the corner 13c, by the front portion 13a and the side portion 13b.

[0032] As shown in Figures 6-8 (especially Figure 7), the recess 14 has a first inclined surface 14a, a horizontal surface 14b extending horizontally from the lower end of the first inclined surface 14a toward the rear of the vehicle X2 and inward D2 of the corner 13c, a vertical wall surface 14c extending downward from the vehicle from the bottom surface 14b3 which is the end of the horizontal surface 14b on the inward D2 side of the corner 13c, and a second inclined surface 14d extending downward and rearward from the lower end of the vertical wall surface 14c.

[0033] As shown in Figure 7, the first inclined section 14a and the second inclined section 14d are inclined downwards as they move toward the rear X2 of the vehicle and toward the inward D2 of the corner 13c. The upper end of the first inclined section 14a on the front X1 side is joined to the front part 12a of the fixed frame 12. The rear end of the second inclined section 14d is joined to the front end 11c of the movable panel 11 (i.e., the front end of the front inclined section 11b).

[0034] As shown in Figures 6 and 8, the horizontal section 14b has a triangular shape when viewed from below. The horizontal section 14b has a pair of slanted sides 14b2 that extend inward in the vehicle rear X2 and vehicle width direction Y to form an obtuse angle section 14b1, and a base section 14b3 that extends in the direction Y1 outward in the vehicle width direction Y as it approaches the vehicle rear X2. As is clear from Figure 6, this base section 14b3 constitutes the end of the horizontal section 14b on the inner D2 side of the corner section 13c. The obtuse angle section 14b1 has an angle θ1 greater than 90 degrees, and is greater than the angles θ2 and θ3 between each of the pair of slanted sides 14b2 and the base section 14b3.

[0035] A larger area of ​​the horizontal portion 14b is preferable because it increases the depth of the recess 14 (the depth toward the inner D2 of the corner portion 13c), making the corner portion 13c more easily deformable. To increase the area of ​​the horizontal portion 14b, it is preferable that the pair of slanted sides 14b2 that constitute the triangular shape of the horizontal portion 14b extend as close as possible to the boundary line between the fixed frame 12 and the deformable member 13 (i.e., the boundary line between the front portions 12a and 13a and the boundary line between the side portions 12b and 13b) and parallel to the said boundary line. Furthermore, a longer length of the slanted side 14b2 extending toward the rear X2 of the vehicle is preferable in terms of improving the ease with which the corner portion 13c can be bent and improving aerodynamic performance.

[0036] As shown in Figure 6, the bottom portion 14b3, which is the inner D2 side end of the corner portion 13c at the end of the horizontal portion 14b, is composed of a gently curved surface to allow airflow during vehicle travel to flow towards the rear X2. Specifically, the bottom portion 14b3 is composed of a curved surface with a larger radius of curvature (radius of curvature R2 (>R1)) than the curved surface (radius of curvature R1) of the obtuse angle portion 14b1 at the outer D1 side end of the corner portion 13c.

[0037] The deformation member 13 is positioned along the entire front end 11c of the movable panel 11 (the entire length in the vehicle width direction Y) and along the range A of the side ends 11e on both sides in the vehicle width direction Y, excluding the rear end 11d.

[0038] More specifically, at the front portion 4a of the under cover 4, as shown in Figures 5, 10, and 12, the front end portion 13d of the deformation member 13 is joined to the rear end portion 12a1 of the front portion 12a of the fixed frame 12. The rear end portion 13e of the deformation member 13 is joined to the front end portion 11c of the movable panel 11. It is preferable that the front end portion 11c of the movable panel 11 be flat, as this facilitates the joining of the deformation member 13, which is made of elastomer. The joining point P2 between the rear end portion 13e of the deformation member 13 and the front end portion 11c of the movable panel 11, as shown in Figure 10, is positioned slightly above (about 5 mm above) the front sloping portion 11b of the movable panel 11. Therefore, there is no risk of the joining point P2 interfering with the road surface (or the slope S described later), and the front sloping portion 11b will interfere with the road surface before the joining point P2.

[0039] Furthermore, on the side portion 4b of the under cover 4, as shown in Figures 5 and 9, the outer end 13f of the deformation member 13 in the vehicle width direction Y1 is joined to the lower end 12b1 of the side portion 12b of the fixed frame 12. The inner end 13g of the deformation member 13 in the vehicle width direction Y2 is joined to the side end 11e of the movable panel 11. The joint point P1 between the end 13g of the deformation member 13 and the side end 11e of the movable panel 11, as shown in Figure 9, is positioned slightly above (about 5 mm above) the bottom surface 11a of the movable panel 11. Therefore, there is no risk of the joint point P1 interfering with the road surface (or the slope S described later), and the bottom surface 11a will interfere with the road surface before the joint point P1.

[0040] Furthermore, it is preferable that the front end 11c and side end 11e of the movable panel 11 are flat, as this facilitates the joining of the deformable member 13 made of different materials such as elastomer.

[0041] As shown in Figures 9-10 above, the deformable member 13 is connected to the movable panel 11 and the fixed frame 12 with a length that allows for some slack, so it does not obstruct the movement of the movable panel 11 in the vertical Z direction.

[0042] (Description of the movable panel 11 and fixed frame 12) Next, the movable panel 11 and the fixed frame 12 will be described. Note that the shape and structure of the movable panel 11 and the fixed frame 12 are not particularly limited in this invention, and various modifications are possible.

[0043] As shown in Figures 5 and 12, the movable panel 11 has a flat bottom surface 11a and a forward sloped surface 11b that slopes upward from the front end of the bottom surface 11a toward the front side X1 of the vehicle. The front end 11c and the side ends 11e on both sides in the vehicle width direction Y, excluding the rear end 11d, are spaced apart from the fixed frame 12 (see Figure 5). On the other hand, the rear end 11d of the movable panel 11 is fixed to the fixed frame 12 (specifically, the rear fixing part 12d). Therefore, the movable panel 11 is partially supported by the fixed frame 12 at the rear end 11d in a cantilevered state.

[0044] The fixed frame 12 is a frame fixed to the bottom surface of the vehicle body 1, as shown in Figures 5 and 12. The fixed frame 12 has a front portion 12a, a pair of side portions 12b extending rearward X2 from both ends of the front portion 12a in the vehicle width direction Y, a front fixing portion 12c fixed to the bottom surface of the bumper 3 of the vehicle body 1, and a rear fixing portion 12d fixed to the suspension cross member 20 of the vehicle body 1 (a cross member extending in the vehicle width direction Y, located rearward X2 from the bumper 3). The front portion 12a is inclined upward as it moves forward X1, at the same inclination angle as the front sloping portion 11b described above.

[0045] The movable panel 11 and the fixed frame 12 are manufactured from resin or metal materials that are less prone to deformation than the deformable member 13 described above. For example, the movable panel 11 and the fixed frame 12 are made from resin materials that are less prone to deformation, such as polypropylene. The movable panel 11 has sufficient bending rigidity to swing by elastic deformation in the vertical Z direction.

[0046] Next, the arrangement and dimensions of the under cover 4 will be explained with reference to Figure 12. Here, the normal road surface is defined as the normal driving surface RBL of the vehicle, and the road surface interference line RCL, which is at a predetermined height HC from the driving surface RBL, is defined as the height of obstacles and steps on the road surface.

[0047] The height HC of the road surface interference line (RCL) is set considering the type of vehicle (such as a regular passenger car or SUV) and the expected driving environment, and is set to approximately 100-130 mm, for example.

[0048] With respect to the running surface RBL, the height HB of the bottom portion 11a of the movable panel 11 is set to a height that does not come into contact with the running surface RBL during normal driving, and is lower than the height HC of the road surface interference line RCL. This height HB is preferably a height at which the negative pressure decreases on the rear side X2 of the bottom portion 11a when the vehicle is in motion.

[0049] Furthermore, the height HD of the front end portion 11c of the movable panel 11 is preferably as high as possible (so that the deformable member 13 does not interfere with the road surface) and it is preferable that only the movable panel 11 does not interfere with the road surface, and if possible, it is better that it is greater than the height HC of the road surface interference line RCL.

[0050] Furthermore, the inclination angle θ of the front portion 4a of the under cover 4 (specifically, the forward sloping portion 11b of the movable panel 11 and the front portion 12a of the fixed frame 12) with respect to the running surface RBL is set to be greater than the angle of an inclined surface expected in usage conditions in which the vehicle may be driven under normal operating conditions, such as a slope S expected when driving on a typical inclined road or when driving off-road (i.e., an inclined surface that assumes a scenario in which the vehicle rapidly goes up and down a bank along the line connecting the contact point of the front wheels 2 and the front end of the bumper 3 when driving off-road).

[0051] Furthermore, in the front portion 4a of the under cover 4, it is preferable that the deformation member 13 be set so as to reduce the width H2 in the vertical Z direction and increase the width W2 in the front-rear X direction, as shown in Figure 10, so as not to interfere with the slope S.

[0052] In order to increase the range of swing in the vertical Z direction of the movable panel 11, which is supported in a cantilevered manner by the fixed frame 12 as described above, it is preferable that the length of the front-rear cross-section of the deformable member 13 at the front portion 4a of the under cover 4 (i.e., the total length of the portion that extends curved from the front end 13d to the rear end 13e) is greater than the length of the cross-section of the deformable member 13 at the side portion 4b of the under cover 4 (i.e., the total length of the portion that extends curved from the outer end 13f in the vehicle width direction to the inner end 13g in the vehicle width direction), as shown in Figures 9-10.

[0053] Furthermore, as shown in Figures 10 and 12, the deformation member 13 is located between the front end 11c of the movable panel 11 and the fixed frame 12. If the deformation member 13 goes above the front end 13d of the deformation member 13 when the front end 11c of the movable panel 11 moves upward, it may be pulled and damaged. Therefore, to avoid damage, it is preferable that the deformation member 13 extends to a length such that when the front end 11c of the movable panel 11 moves upward, it is below the height of the front end 13d of the deformation member 13. Accordingly, it is preferable that the horizontal length W2 (length in the front-rear direction X) of the deformation member 13 at the front portion 4a of the under cover 4 shown in Figure 10 is sufficiently longer than the horizontal length W1 (length in the vehicle width direction Y) of the deformation member 13 at the side portion 4b of the under cover 4 shown in Figure 9.

[0054] As described above, when the movable panel 11 and the fixed frame 12 are made of a resin material such as polypropylene, and the deformable member 13 is made of a film of a resin material such as elastomer, the under cover 4 can be integrally formed by two-color molding using two types of resin materials, polypropylene and elastomer.

[0055] (Features of this embodiment) (1) The understructure of the vehicle in this embodiment includes an under cover 4 that covers the bottom surface of the vehicle body in the area in front of a pair of front wheels 2 and between the pair of front wheels 2. The under cover 4 has a movable panel 11 that is movable in the vertical direction Z, a fixed frame 12 positioned above the movable panel 11 and fixed to the bottom surface of the vehicle body 1, and a deformable member 13 that connects at least the front end 11c of the movable panel 11 to the fixed frame 12. The deformable member 13 is made of a material softer than the movable panel 11 and deforms when the movable panel 11 comes into contact with the road surface.

[0056] As shown in Figures 2-8, the deformable member 13 has a front portion 13a that extends in the vehicle width direction Y on the front side of the under cover 4, and a pair of side portions 13b that extend from both ends of the front portion 13a toward the rear of the vehicle X2.

[0057] A recess 14 is formed in the corner 13c of the deformable member 13, which is recessed inward D2 of the corner 13c, by the front portion 13a and the side portion 13b.

[0058] With this configuration, when the movable panel 11 comes into contact with the road surface, the movable panel 11 lifts up. At this time, the corners 13c at both ends of the front portion 13a of the deformable member 13 deform smoothly, bending inward D2 of the corners 13c with the recess 14 as the bending starting point. As a result, the movable panel 11 can be lifted up with a small load. Therefore, it is possible to reliably reduce the rigidity of the corners 13c at both ends of the front end of the under cover 4, where the load is greatest when it comes into contact with the road surface. As a result, it becomes possible to prevent damage to the under cover 4 when it comes into contact with the road surface.

[0059] Since the deformable member 13 has the shape of a membrane with recesses 14 formed on it, it can be manufactured with a constant plate thickness. This ensures the productivity of the under cover 4. Moreover, since the deformable member 13 has the shape of a membrane with recesses 14 but no through holes, which provides a high level of sealing, it can prevent water and foreign matter from entering the inside of the under cover 4 through the deformable member 13 when the vehicle is in motion.

[0060] (2) In the vehicle understructure of this embodiment, as shown in Figures 6 to 8, the recess 14 has a horizontal portion 14b that extends horizontally toward the rear X2 of the vehicle and toward the inward D2 of the corner portion 13c, and a vertical wall portion 14c that extends downward from the vehicle from the bottom portion 14b3, which is the end of the horizontal portion 14b that is on the inward D2 side of the corner portion 13c.

[0061] With this configuration, when the movable panel 11 comes into contact with the road surface, the horizontal portion 14b and the vertical wall portion 14c that constitute the recess 14 of the corner portion 13c of the deformable member 13 fold smoothly as the movable panel 11 rises. As a result, the deformable member 13 deforms more smoothly toward the inward D2 of the corner portion 13c, improving the damage prevention effect of the under cover 4.

[0062] Furthermore, since the horizontal portion 14b of the recess 14 extends to the rear X2 of the vehicle, the horizontal portion 14b can rectify the airflow during vehicle operation, thereby suppressing the generation of turbulence in the recess 14.

[0063] As a result, it is possible to achieve both improved breakability of the corner portion 13c of the deformable member 13 and improved aerodynamic performance.

[0064] (3) In the vehicle understructure of this embodiment, as shown in Figure 6, the bottom portion 14b3, which is the inner D2 side end of the corner portion 13c among the ends of the horizontal portion 14b, is composed of a curved surface (radius of curvature R2 (>R1)) with a larger radius of curvature than the curved surface (radius of curvature R1) of the obtuse angle portion 14b1 at the outer D1 side end of the corner portion 13c.

[0065] With this configuration, the area of ​​the horizontal section 14b can be increased, and the portion extending to the rear X2 of the vehicle is enlarged, allowing air to flow more smoothly to the rear X2. As a result, aerodynamic performance is further improved.

[0066] (4) In the vehicle understructure of this embodiment, as shown in Figures 6 and 8, the horizontal portion 14b has a triangular shape when viewed from below. The horizontal portion 14b has a pair of slanted sides 14b2 that extend inward towards the rear X2 of the vehicle and inward in the vehicle width direction Y, forming an obtuse angle portion 14b1, and a base portion 14b3 that extends in a direction Y1 toward the outside in the vehicle width direction Y as it approaches the rear X2 of the vehicle.

[0067] With this configuration, the horizontal portion 14b of the recess 14 forms the triangular shape described above, resulting in a simple shape. Therefore, it becomes easier to manufacture an under cover 4 that balances the ease of breaking of the corner portion 13c of the deformable member 13 with improved aerodynamic performance, thereby improving the productivity of the under cover 4.

[0068] (Other features of this embodiment) The following describes other features of this embodiment.

[0069] (5) In the vehicle understructure of this embodiment, as shown in Figures 2-10 and 12, the under cover 4 includes a movable panel 11, a fixed frame 12, and a deformable member 13 that connects the movable panel 11 and the fixed frame 12. The deformable member 13 is made of a material softer than the movable panel 11 and is configured to deform when the movable panel 11 comes into contact with the road surface, thereby enabling the movable panel 11 to move upward.

[0070] According to this configuration, the under cover 4 has a movable panel 11, a fixed frame 12 fixed to the bottom surface of the vehicle body 1, and a deformable, flexible deformable member 13 connecting at least the front end 11c of the movable panel 11 to the fixed frame 12. Therefore, as shown in Figure 12, when the movable panel 11 of the under cover 4 comes into contact with an obstacle or step protruding from the road surface while the vehicle is in motion, that is, when the movable panel 11 interferes with the road surface, the flexible deformable member 13 deforms and moves upward to the movable panel 11, thereby reducing the load on the movable panel 11. This makes it possible to prevent damage to the under cover 4 when it interferes with the road surface.

[0071] Furthermore, with the above configuration, there is no risk of damage to the movable panel 11, making it possible to position the flat bottom surface 11a of the movable panel 11 at a height close to the road surface. As a result, when the vehicle is in motion, the negative pressure on the flat bottom surface 11a of the movable panel 11 decreases from the front end towards the rear, allowing air to flow more easily, and the pair of front wheels 2 located on both sides of the movable panel 11 in the vehicle width direction are less likely to be hit by the airflow. Consequently, it becomes possible to reduce air resistance during driving.

[0072] Furthermore, in order to improve the effect of reducing air resistance, it is preferable that the length of the movable panel 11 in the front-rear direction X, especially the length of the bottom surface 11a, be long. For this reason, it is preferable that the position of the front end 11c of the movable panel 11 be as far forward as possible.

[0073] (6) In the vehicle understructure of this embodiment, the movable panel 11 is made of polypropylene. The deformable member 13 is made of elastomer.

[0074] With this configuration, the deformable member 13 is made of elastomer, making it significantly softer and more deformable than the movable panel 11 made of polypropylene. Therefore, when the movable panel 11 comes into contact with the road surface, the deformable member 13 deforms significantly with a small load, enabling the movable panel 11 to move quickly and smoothly upward. As a result, it becomes possible to reliably prevent damage to the under cover 4 when it comes into contact with the road surface.

[0075] (7) In the vehicle understructure of this embodiment, as shown in Figures 5 and 12, the deformation member 13 is arranged along the entire front end 11c of the movable panel 11 and along the range A of the side ends 11e on both sides in the vehicle width direction, excluding the rear end 11d. The rear end 11d of the movable panel 11 is fixed to the fixed frame 12.

[0076] With this configuration, the area A of the movable panel 11, excluding the front end 11c and both side ends 11e and the rear end 11d, is connected to the fixed frame 12 via the deformation member 13, and the rear end 11d of the movable panel 11 is partially fixed to the fixed frame 12. Therefore, since the movable panel 11 is supported by the fixed frame 12 in a cantilevered manner only at the rear end 11d, the front end 11c of the movable panel 11 can swing significantly in the vertical direction Z when it comes into contact with the road surface. As a result, it becomes possible to reliably prevent damage to the under cover 4 when it comes into contact with the road surface.

[0077] In this embodiment, the movable panel 11, supported in a cantilevered state, is made of a resin material such as polypropylene, which is less deformable than elastomer but can undergo elastic deformation when it comes into contact with the road surface. Therefore, when the movable panel 11 comes into contact with the road surface, it swings upward while undergoing elastic deformation (bending deformation), but when the road surface contact is removed, the movable panel 11 returns to its normal horizontal position due to its own restoring force. The soft deformable member 13 deforms (bends or is stretched) while following the vertical movement of the movable panel 11.

[0078] (8) In the vehicle understructure of this embodiment, it is preferable that the length of the longitudinal cross-section of the deformation member 13 in the front portion 4a of the under cover 4 shown in Figure 10 (i.e., the total length of the portion that extends curved from the front end 13d to the rear end 13e) is greater than the length of the cross-section of the deformation member 13 in the vehicle width direction of the side portion 4b of the under cover 4 shown in Figure 9 (i.e., the total length of the portion that extends curved from the outer end 13f in the vehicle width direction to the inner end 13g in the vehicle width direction).

[0079] With this configuration, the range of oscillation of the front end 11c of the movable panel 11 in the vertical direction Z is increased, making it possible to more reliably prevent damage to the under cover 4 when it comes into contact with the road surface.

[0080] (9) In the vehicle understructure of this embodiment, as shown in Figures 10 and 12, the deformation member 13 extends between the front end 11c of the movable panel 11 and the fixed frame 12 to a length such that when the front end 11c of the movable panel 11 moves upward, the deformation member 13 is less than or equal to the height of the front end 13d of the deformation member 13.

[0081] With this configuration, the deformation member 13 extends to the above length between the front end 11c of the movable panel 11 and the fixed frame 12. As a result, when the movable panel 11 comes into contact with the road surface and the front end 11c of the movable panel 11 moves upward, it will be below the height of the front end 13d of the deformation member 13. This eliminates the risk of the front end 11c of the movable panel 11 moving above the front end 13d of the deformation member 13 and pulling on the deformation member 13, causing damage.

[0082] (modified version) In the above embodiment, the recess 14 formed in the corner 13c of the deformable member 13 has a triangular horizontal portion 14b, but the horizontal portion 14b is longer in the vehicle's longitudinal direction X or vehicle width direction Y so that the corner 13c is easier to break. The recess 14 may have a recess structure other than a triangular shape as long as the shape makes the corner 13c easier to break. The recess 14 may have various shapes as long as it functions as a starting point for breaking the corner 13c, for example, it may have a semicircular dimple shape or a bellows shape. [Explanation of Symbols]

[0083] 1. Vehicle body 2 Front wheels 4 Undercover 4a Front part 4b Side part 11 Movable Panels 12 Fixed Frame 13 Deformed member 13a Front part 13b Side part 13c Corner 13d front end 13e Rear end 13f Outer edge in the vehicle width direction 13g Inner end in the vehicle width direction 14 recess 14a First slope section 14b Horizontal part 14b1 Obtuse angle part 14b2 Hypotenuse part 14b3 Base 14c Vertical wall section 14d 2nd slope section

Claims

1. It is equipped with an under cover that covers the bottom surface of the vehicle body in front of a pair of front wheels and in the area between the pair of front wheels, The under cover comprises a movable panel that can move vertically, a fixed frame positioned above the movable panel and fixed to the bottom surface of the vehicle body, and a deformable member that connects the movable panel and the fixed frame. The deformable member is made of a softer material than the movable panel and deforms when the movable panel comes into contact with the road surface. The deformable member has a front portion extending in the vehicle width direction on the front side of the under cover, and a pair of side portions extending towards the rear of the vehicle from both ends of the front portion. The corner formed by the front and side portions of the deformed member has a recess formed inward at the corner. A vehicle understructure characterized by the following features.

2. In the vehicle understructure according to claim 1, The recess has a horizontal portion extending horizontally toward the rear of the vehicle and toward the corner, and a vertical wall portion extending downward from the end of the horizontal portion that is toward the corner. A vehicle understructure characterized by the following features.

3. In the vehicle understructure according to claim 2, The end of the horizontal portion on the inner side of the corner is composed of a curved surface with a larger radius of curvature than the curved surface of the outer side of the corner. A vehicle understructure characterized by the following features.

4. In the vehicle understructure according to claim 2, The horizontal portion has a triangular shape when viewed from below. The horizontal portion has, as part of the triangular shape, a pair of slanted sides that extend inward in the vehicle rearward and vehicle width direction, respectively, forming an obtuse angle, and a base that extends outward in the vehicle width direction as it approaches the vehicle rearward. A vehicle understructure characterized by the following features.

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