Vehicle undercarriage

Abstract

The objective is to provide a vehicle undercarriage structure that can simultaneously prevent damage to the underbody cover during road contact and suppress abnormal noise. [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 member 13. 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 13 is positioned along the entire front end 11c of the movable panel 11 and the area 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. The movable panel 11 has at least one first rib 21 erected on the upper surface 11f of the movable panel 11.

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 traveling.

[0003] For example, Patent Document 1 discloses a vehicle provided with an undercover that descends during high-speed traveling 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 has descended during high-speed traveling, thereby improving the adhesion of the vehicle body to the road surface and enhancing the stability during high-speed traveling.

[0004] Further, Patent Document 2 discloses a vehicle provided with a movable tire cover that descends in front of a tire during high-speed traveling of the vehicle. This movable tire cover prevents wind from hitting the tire during high-speed traveling.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0005]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] In both of the above two structures, when 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.

[0007] Furthermore, if the underbody cover's bottom surface is modified to allow it to bend upward when it comes into contact with the road surface (for example, to a cantilevered configuration), the plate thickness needs to be increased to raise the rigidity of the bottom surface so that it is not damaged when it comes into contact with the road surface or vibrates due to airflow while the vehicle is in motion. As a result, there is a problem in that it is not possible to suppress the generation of abnormal noise when it comes into contact with the road surface.

[0008] This invention has been made in view of the circumstances described above, and aims to provide a vehicle undercarriage structure that can achieve both prevention of damage to the undercarriage cover during road surface contact and suppression of abnormal noise. [Means for solving the problem]

[0009] To solve the aforementioned problems, the vehicle understructure of the present invention comprises 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, wherein the under cover comprises 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, wherein the deformable member is made of a material softer than the movable panel and deforms when the movable panel comes into contact with the road surface, the deformable member is positioned along the entire front end of the movable panel and the side ends on both sides in the vehicle width direction, excluding the rear end, the rear end of the movable panel is fixed to the fixed frame, and the movable panel has at least one first rib erected on the upper surface of the movable panel.

[0010] In this configuration, the front end and the rear ends of both sides of the movable panel are connected to the fixed frame via a deformation member, and the rear end of the movable panel is partially fixed to the fixed frame. Therefore, since the movable panel is supported by the fixed frame in a cantilevered manner only at its rear end, when it comes into contact with the road surface, the front end of the movable panel can swing significantly in the vertical direction along with the deformation of the deformation member. As a result, it becomes possible to reliably prevent damage to the underbody cover when it comes into contact with the road surface.

[0011] Furthermore, since the first rib is erected on the upper surface of the movable panel, the rigidity of the movable panel is improved without increasing the thickness of the panel. As a result, it is possible to suppress the generation of abnormal noise when the movable panel swings vertically during road contact.

[0012] As a result, it is possible to achieve both prevention of damage to the underbody cover during road contact and suppression of abnormal noise.

[0013] In the above-described understructure of the vehicle, it is preferable that the plurality of first ribs each extend in the longitudinal direction of the vehicle and are spaced apart from each other in the width direction of the vehicle.

[0014] With this configuration, since the multiple first ribs erected on the upper surface of the movable panel each extend in the longitudinal direction of the vehicle and are spaced apart from each other in the width direction of the vehicle, the vertical bending rigidity of the movable panel, which is supported in a cantilevered state with its rear end fixed, is further improved, and the generation of abnormal noise when it comes into contact with the road surface can be further suppressed. As a result, it is possible to improve both the effect of preventing damage to the under cover when it comes into contact with the road surface and the effect of suppressing abnormal noise.

[0015] In the above-described vehicle understructure, the fixed frame has at least one second rib erected on the upper surface of the fixed frame, and it is preferable that the height of the first rib is greater than the height of the second rib.

[0016] With this configuration, the first rib erected on the movable panel, which swings vertically when it comes into contact with the road surface, is higher than the second rib erected on the fixed frame. This makes it possible to improve the rigidity of the movable panel while simultaneously improving the rigidity of the fixed frame. As a result, it is possible to improve both the effect of preventing damage to the underbody cover when it comes into contact with the road surface and the effect of suppressing abnormal noise.

[0017] In the above vehicle lower structure, it is preferable that the movable panel further includes at least one third rib that is erected on the upper surface of the movable panel, extends in the vehicle width direction, and connects the plurality of first ribs.

[0018] According to this configuration, the third rib on the upper surface of the movable panel extends in the vehicle width direction and connects the plurality of first ribs, so that the bending rigidity of the movable panel in both the vehicle front-rear direction and the vehicle width direction is further improved. As a result, it is possible to further improve both the effect of preventing damage to the undercover during road surface interference and the effect of suppressing abnormal noise.

[0019] In the above vehicle lower structure, it is preferable that the height of the first rib is higher than the height of the third rib. According to this configuration, since the plurality of first ribs extending in the vehicle front-rear direction on the upper surface of the movable panel are higher than the third rib extending in the vehicle width direction, the vertical bending rigidity of the movable panel, which has its rear end fixed and is supported in a cantilever state, is further improved, and the generation of abnormal noise during road surface interference can be further suppressed. As a result, it is possible to further enhance both the effect of preventing damage to the undercover during road surface interference and the effect of suppressing abnormal noise. Effects of the Invention

[0020] As described above, according to the vehicle lower structure of the present invention, it is possible to achieve both prevention of damage to the undercover and suppression of abnormal noise during road surface interference. Brief Description of the Drawings

[0021] [Figure 1] This is a perspective view of the undercover showing the main part of the vehicle lower structure according to the embodiment of the present invention and its peripheral part, as viewed from the obliquely front left lower side. [Figure 2] This is an enlarged perspective view of the undercover of Fig. 1 as viewed from the front right lower side. [Figure 3] This is a bottom view of the left portion of the undercover of Fig. 1. [Figure 4] This is a side view of the front portion of the left side surface of the undercover of Fig. 1. [Figure 5] It is a perspective view of the undercover in Fig. 1 as viewed from the upper left. [Figure 6] It is a front view of the front left half of the vehicle body in Fig. 1. [Figure 7] It is a sectional view taken along line VII-VII in Fig. 6. [Figure 8] It is a perspective view of the right half of the undercover in Fig. 1 as viewed from the oblique lower right. [Figure 9] It is a sectional view taken along line IX-IX in Fig. 8. [Figure 10] It is a sectional view taken along line X-X in Fig. 8. MODES FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, the vehicle lower structure according to the embodiment of the present invention will be described in detail with reference to the drawings.

[0023] Fig. 1 discloses a vehicle lower structure provided with an undercover 4 as an embodiment of the vehicle lower structure of the present invention.

[0024] Specifically, the vehicle lower structure shown in Fig. 1 includes the undercover 4 that is movable in the vertical direction Z and covers the bottom surface of the vehicle body 1 in the range between the pair of front wheels 2 at the front side X1 of the pair of front wheels 2. As shown in Fig. 1 and Figs. 6 to 7, the undercover 4 is disposed in the range from the vicinity of the front end of the bumper 3 on the bottom surface of the vehicle body 1 to the front end of the front wheel 2.

[0025] Further, in the vehicle lower structure of the present embodiment, as shown in Fig. 1, a floor panel 5 that covers the bottom surface of the vehicle body 1 is disposed on the vehicle rear side X2 relative to the undercover 4. Furthermore, a pair of side undercovers 6 are disposed on both sides of the undercover 4 in the vehicle width direction Y. Note that these floor panel 5 and side undercovers 6 are not essential components in the present invention and may be replaced with other members.

[0026] Hereinafter, the specific structure of the undercover 4 will be described in further detail.

[0027] As shown in Figures 2 to 10, 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 8)) and the fixed frame 12.

[0028] As shown in Figures 7-8, 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 8). 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.

[0029] The fixed frame 12 is a frame fixed to the bottom surface of the vehicle body 1, as shown in Figures 7-8. The fixed frame 12 has a front section 12a, a pair of side sections 12b extending rearward X2 from both ends of the front section 12a in the vehicle width direction Y, a front fixing section 12c fixed to the bottom surface of the bumper 3 of the vehicle body 1, and a rear fixing section 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 section 12a is inclined upward as it moves forward X1, at the same inclination angle as the front slope section 11b described above.

[0030] The movable panel 11 and the fixed frame 12 are manufactured from deformation-resistant resin or metal materials. For example, the movable panel 11 and the fixed frame 12 are made from deformation-resistant resin materials such as polypropylene. The movable panel 11 has sufficient bending rigidity to swing by elastic deformation in the vertical Z direction.

[0031] (Explanation of the 1st rib 21 to the 4th rib 24) As shown in Figure 5, four types of ribs, the first to fourth ribs 24, are provided on the upper side of the under cover 4 for reinforcement. The first rib 21 and the second rib 22 extend in the vehicle longitudinal direction X, while the third rib 23 and the fourth rib 24 extend in the vehicle width direction Y.

[0032] Looking at it in more detail, the movable panel 11 has at least one (multiple in Figure 5) first ribs 21 and at least one (multiple in Figure 5) third ribs 23 erected on its upper surface 11f. The first ribs 21 and the third ribs 23 are integrally formed with the movable panel 11.

[0033] Each of the multiple first ribs 21 extends in the vehicle's longitudinal direction X and is spaced apart from each other in the vehicle's width direction Y. In Figure 5, the first ribs 21 extend to the front and rear ends of the movable panel 11, but they do not necessarily have to extend to the front and rear ends of the movable panel 11.

[0034] Multiple third ribs 23 extend in the vehicle width direction Y and connect multiple first ribs 21. The height of the first ribs 21 is greater than the height of the third ribs 23. Therefore, the first ribs 21 extending in the vehicle longitudinal direction X have higher bending rigidity than the third ribs.

[0035] On the other hand, the fixed frame 12 has at least one (multiple in Figure 5) second rib 22 and at least one (one in Figure 5) fourth rib 24 erected on its upper surface 12e.

[0036] Multiple second ribs 22 each extend in the vehicle's longitudinal direction X and are spaced apart from each other in the vehicle's width direction Y. The fourth rib 24 extends in the vehicle's width direction Y and connects the multiple second ribs 22. The second ribs 22 and the fourth rib 24 are integrally formed with the fixed frame 12.

[0037] The height of the first rib 21 is greater than the height of the second rib 22. Therefore, the first rib 21 on the movable panel 11 side has higher bending rigidity than the second rib 22 on the fixed frame 12 side.

[0038] The movable panel 11 is supported in a cantilevered state, with its rear end 11d fixed to the rear fixing part 12d of the fixed frame 12. It can bend and deform in the vertical Z direction when it hits a road surface, but as described above, the bending rigidity is improved by having multiple first ribs 21 and third ribs 23. Therefore, it is not necessary to increase the thickness of the movable panel 11, and thus the generation of abnormal noise when it hits a road surface can be suppressed.

[0039] More specifically, the multiple first ribs 21 extending in the longitudinal direction X of the vehicle elastically deform as they bend upward together with the movable panel 11 of the under cover 4 when the movable panel 11 makes contact with the road surface. When the movable panel 11 leaves the ground after the road surface contact ends, the multiple first ribs 21 generate a downward reaction force due to their own elastic force, pushing down the movable panel 11 and returning it to its initial position before the road surface contact.

[0040] In other words, the multiple first ribs 21 can withstand the impact the movable panel 11 receives when it comes into contact with the road surface by accumulating elastic energy through bending deformation in a side view. That is, the multiple first ribs 21 can withstand the moment around the vehicle's left-right axis (the axis extending in the vehicle width direction Y) as a road surface input.

[0041] Furthermore, the multiple first ribs 21 can suppress deformation of the movable panel 11 due to wind pressure when the vehicle is in motion. In addition, the multiple first ribs 21 function as reinforcing materials to prevent damage to the movable panel 11 when it comes into contact with the road surface.

[0042] On the other hand, the third rib 23 extending in the vehicle width direction Y is connected to a plurality of first ribs 21 extending in the vehicle longitudinal direction X, so when the movable panel 11 comes into contact with the road surface, it is possible to distribute (flow) the force evenly to each connection point with the first rib 21. As a result, when the movable panel 11 comes into contact with the road surface, it is possible to bend upward in a cantilevered state while suppressing twisting around the axis extending in the vehicle longitudinal direction X.

[0043] In Figure 5, the multiple first ribs 21 are wavy in shape to correspond to the wave shape near the rear end 11d of the movable panel 11 (a shape that curves (wavy) in the vertical direction Z as it moves towards the rear X2), but the present invention is not limited to this. The first ribs 21 only need to extend in the longitudinal direction X of the vehicle in order to reinforce the movable panel 11 which bends and deforms in the vertical direction Z.

[0044] Furthermore, the first rib 21 only needs to extend in the longitudinal direction X of the vehicle, and may not only have a shape that extends at a constant height, but may also have a shape that becomes lower as it goes towards the rear X2 (i.e., as it approaches the rear end 11d).

[0045] Furthermore, the first rib 21 may be partially tapered to facilitate demolding when molding the under cover 4.

[0046] The following describes other configurations of this embodiment.

[0047] 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 7, 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.

[0048] Specifically, the deformable member 13 is made of a deformable elastomer film. The deformable 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.

[0049] More specifically, at the front portion 4a of the under cover 4, as shown in Figures 7-8 and 10, the front end portion 13b of the deformable member 13 is joined to the rear end portion 12a1 of the front portion 12a of the fixed frame 12. The rear end portion 13c of the deformable 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 deformable member 13, which is made of elastomer. The joining point P2 between the rear end portion 13c of the deformable 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.

[0050] Furthermore, on the side portion 4b of the under cover 4, as shown in Figures 8-9, the outer end 13d 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 13e 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 13e 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.

[0051] 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.

[0052] 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.

[0053] Next, the arrangement and dimensions of the under cover 4 will be explained with reference to Figure 7. 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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 driving on a typical inclined road or a slope S expected during off-road driving (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 during off-road driving).

[0058] Furthermore, in the front portion 4a of the under cover 4, it is preferable to set the deformation member 13 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 slopes S1 to S3 described above.

[0059] 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 on the fixed frame 12 as described above, it is preferable that the length of the front-rear cross-section of the deformable member 13 on the front portion 4a of the under cover 4 (i.e., the total length of the portion that extends curved from the front end 13b to the rear end 13c) is greater than the length of the cross-section of the deformable member 13 on the side portion 4b of the under cover 4 (i.e., the total length of the portion that extends curved from the outer end 13d in the vehicle width direction to the inner end 13e in the vehicle width direction), as shown in Figures 9-10.

[0060] Furthermore, as shown in Figures 7 and 10, 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 13b of the deformation member 13 when the front end 11c of the movable panel 11 moves upward, it may pull on the deformation member 13 and cause damage. 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 13b 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.

[0061] 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.

[0062] Since the deformable member 13 is made of a membrane, 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.

[0063] Furthermore, in this embodiment, as shown in Figures 2-4 and 8, the deformable member 13, which is made of a membrane, 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 the deformation of the deformable member 13.

[0064] (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 front of a pair of front wheels and in the area between the pair of front wheels. The under cover 4 has a movable panel 11 that is movable in the vertical direction Z, a fixed frame 12 that is positioned above the movable panel 11 and fixed to the bottom surface of the vehicle body, and a deformable member 13 that connects the movable panel 11 and the fixed frame 12.

[0065] 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 13 is positioned 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 Y, excluding the rear end 11d. The rear end 11d of the movable panel 11 is fixed to the fixed frame 12.

[0066] As shown in Figure 5, the movable panel 11 has at least one first rib 21 erected on the upper surface 11f of the movable panel 11. There may be at least one first rib 21, just one, or multiple first ribs 21.

[0067] With this configuration, the area A of the movable panel 11, excluding the rear ends 11d of both ends 11e and the front end 11c and both sides 11e, 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 state only at the rear end 11d, when it comes into contact with the road surface, the front end of the movable panel 11 can swing significantly in the vertical direction Z along with the deformation of the deformation member 13. As a result, it becomes possible to reliably prevent damage to the under cover 4 when it comes into contact with the road surface.

[0068] Furthermore, since the first rib 21 is erected on the upper surface 11f of the movable panel 11, the rigidity of the movable panel 11 is improved without increasing the thickness of the movable panel 11. Therefore, it is possible to suppress the generation of abnormal noise when the movable panel 11 swings in the vertical direction Z during road contact.

[0069] As a result, it is possible to achieve both prevention of damage to the under cover 4 when it comes into contact with the road surface and suppression of abnormal noise.

[0070] (2) In the vehicle understructure of this embodiment, as shown in Figure 5, the multiple first ribs 21 each extend in the vehicle longitudinal direction X and are spaced apart from each other in the vehicle width direction Y.

[0071] With this configuration, since the multiple first ribs 21 erected on the upper surface 11f of the movable panel 11 each extend in the vehicle longitudinal direction X and are spaced apart from each other in the vehicle width direction Y, the bending rigidity in the vertical direction Z of the movable panel 11, which is supported in a cantilevered state with its rear end 11d fixed, is further improved, and the generation of abnormal noise when it comes into contact with the road surface can be further suppressed. As a result, it is possible to improve both the effect of preventing damage to the under cover 4 when it comes into contact with the road surface and the effect of suppressing abnormal noise.

[0072] (3) In the vehicle understructure of this embodiment, as shown in Figure 5, the fixed frame 12 has at least one second rib 22 erected on the upper surface 11f of the fixed frame 12. The height of the first rib 21 is greater than the height of the second rib 22.

[0073] With this configuration, the first rib 21 erected on the movable panel 11, which swings in the vertical Z direction when it comes into contact with the road surface, is higher than the second rib 22 erected on the fixed frame 12. This makes it possible to improve the rigidity of the movable panel 11 while also improving the rigidity of the fixed frame 12. As a result, it is possible to improve both the effect of preventing damage to the under cover 4 when it comes into contact with the road surface and the effect of suppressing abnormal noise.

[0074] In the above embodiment, the height of the first rib 21 is greater than the height of the second rib 22, but the present invention is not limited to this. That is, in the present invention, the height of the first rib 21 may be less than or equal to the height of the second rib 22. For example, by making the height of the first rib 21 lower than the height of the second rib 22, the rigidity of the movable panel 11 may be reduced, thereby reducing the abnormal noise generated when the movable panel 11 comes into contact with the road surface. Alternatively, by making the height of the second rib 22 higher than the height of the first rib 21, the rigidity of the fixed frame 12 on which the second rib 22 is provided may be improved.

[0075] (4) In the vehicle understructure of this embodiment, the movable panel 11 further has at least one third rib 23 erected on the upper surface 11f of the movable panel 11, extending in the vehicle width direction Y, and connecting a plurality of first ribs 21.

[0076] With this configuration, the third rib 23 on the upper surface 11f of the movable panel 11 extends in the vehicle width direction Y and connects to multiple first ribs 21, so that the bending rigidity of the movable panel 11 is further improved in both the vehicle longitudinal direction X and the vehicle width direction Y. As a result, it is possible to further improve both the effect of preventing damage to the under cover 4 when it comes into contact with the road surface and the effect of suppressing abnormal noise.

[0077] (5) In the vehicle understructure of this embodiment, the height of the first rib 21 is higher than the height of the third rib 23. With this configuration, since the multiple first ribs 21 extending in the vehicle longitudinal direction X on the upper surface 11f of the movable panel 11 are higher than the third rib 23 extending in the vehicle width direction Y, the bending rigidity in the vertical direction Z of the movable panel 11, which is supported in a cantilevered state with its rear end 11d fixed, is further improved, and the generation of abnormal noise when it comes into contact with the road surface can be further suppressed. As a result, both the effect of preventing damage to the under cover 4 when it comes into contact with the road surface and the effect of suppressing abnormal noise can be further improved.

[0078] (Other features of this embodiment) (6) The undercarriage structure of this embodiment, as shown in Figures 1 to 10, 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 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 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.

[0079] With 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 7, 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 from 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.

[0080] 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.

[0081] 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.

[0082] (7) In the vehicle understructure of this embodiment, the movable panel 11 is made of polypropylene. The deformable member 13 is made of elastomer.

[0083] 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.

[0084] 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.

[0085] (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 13b to the rear end 13c) 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 13d in the vehicle width direction to the inner end 13e in the vehicle width direction).

[0086] 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.

[0087] (9) In the vehicle understructure of this embodiment, as shown in Figures 7 and 10, 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 13b of the deformation member 13.

[0088] 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 13b of the deformation member 13. This eliminates the risk of the front end 11c of the movable panel 11 moving above the front end 13b of the deformation member 13 and pulling on the deformation member 13, causing damage. [Explanation of Symbols]

[0089] 1. Vehicle body 2 Front wheels 4 Undercover 4a Front part 4b Side part 11 Movable Panels 11a Bottom part 11b Front slope 11c Front end 11d Rear end 11e Side edge 12 Fixed Frame 12a Front part 12b Side part 12c Front fixing part 12d Rear fixed part 13 Deformed member 13b Front end 13c Rear end 13d Outer edge in the vehicle width direction 13e Inner end in the vehicle width direction 21. First Rib 22. Second Rib 23 Third Rib

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 deformation member is arranged along the entire front end of the movable panel and the side ends on both sides in the vehicle width direction, excluding the rear end. The rear end of the movable panel is fixed to the fixed frame. The movable panel has at least one first rib erected on its upper surface. A vehicle understructure characterized by the following features.

2. In the vehicle understructure according to claim 1, Each of the multiple first ribs extends in the longitudinal direction of the vehicle and is spaced apart from each other in the width direction of the vehicle. A vehicle understructure characterized by the following features.

3. In the vehicle understructure according to claim 1 or 2, The aforementioned fixed frame has at least one second rib erected on the upper surface of the fixed frame, The height of the first rib is higher than the height of the second rib. A vehicle understructure characterized by the following features.

4. In the vehicle understructure according to claim 2, The movable panel further has at least one third rib erected on the upper surface of the movable panel, extending in the vehicle width direction and connecting a plurality of first ribs. A vehicle understructure characterized by the following features.

5. In the vehicle understructure according to claim 4, The height of the first rib is greater than the height of the third rib. A vehicle understructure characterized by the following features.

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