Vehicle having a directional patterned embossed surface on the underside of the vehicle body, and vehicle undercover member

Abstract

To improve airflows beneath a vehicle body, for example, to enhance the traveling performance of the vehicle.SOLUTION: A vehicle 1 with a travelable vehicle body 2 is disposed with under-cover members 22, 29, 27, 28 on at least one of a front portion and a rear portion of a lower surface 10 of the vehicle body 2. A flat portion 222 of the under-cover member 22 on the front portion is formed with an embossed surface 40 of a directionality pattern to enhance airflows along a front-rear direction of the vehicle body 2. A flat portion 291 of the under-cover members 29, 27, 28 on the rear portion is formed with the embossed surface 40 of a directionality pattern to enhance the airflows along the front-rear direction of the vehicle body 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle having a directional pattern textured surface on the underside of the vehicle body, and to an under-cover member for the vehicle. [Background technology]

[0002] When a vehicle is moving, airflow occurs around the vehicle body, causing air resistance. In Patent Document 1, multiple circular dimples are formed as densely and continuously as possible on the undercover that forms the underside of the vehicle body. This actively generates vortexes in the circular dimples, preventing the airflow flowing from front to rear under the vehicle body from separating from the underside of the vehicle body, thereby reducing air resistance. In addition, in Patent Document 2, an undercover with multiple dimples formed in a row is provided in the center of the front-to-rear direction on the underside of the vehicle body, which actively generates vortexes in the dimples, preventing the airflow flowing from front to rear under the vehicle body from separating from the underside of the vehicle body, thereby reducing air resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-247144 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-024047 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when it comes to vehicle travel, simply reducing air resistance is not enough. For example, if a large amount of airflow flows under the vehicle body and tends to accumulate there, the vehicle body will be pushed up and become more likely to float, which may impair the vehicle's driving performance, such as steering response and straight-line stability. Furthermore, even if multiple circular dimples are formed in a continuous, dense pattern on the under-cover member that forms the underside of the vehicle body as in Patent Document 1, the effect of the multiple densely-spaced circular dimples in promoting airflow is not limited to the direction of the airflow, and it is therefore unlikely that this will effectively prevent impairment of driving performance. For example, the airflow promotion effect will also be exerted on airflow along the vehicle width direction. Furthermore, even if multiple circular dimples are formed in a row on an undercover member located in the central portion of the underside of the vehicle body in the fore-and-aft direction, as in Patent Document 2, it is difficult to say that this can effectively suppress lifting of the front and rear of the vehicle body.

[0005] In this way, it is necessary to improve the airflow under the vehicle body and other aspects of the vehicle to improve driving performance. [Means for solving the problem]

[0006] A vehicle having a directional pattern textured surface on the underside of a vehicle body according to one embodiment of the present invention is a vehicle having a drivable vehicle body, the vehicle body being provided with an undercover member on at least one of a front portion and a rear portion of the underside of the vehicle body, and a directional pattern textured surface that promotes airflow along the fore-and-aft direction of the vehicle body being formed on a flat portion of the undercover member. The embossed surface includes a plurality of ribs formed with a first recess in a short direction along the left-right direction of the vehicle body and a second recess in a long direction along the front-rear direction of the vehicle body, and the plurality of ribs adjacent in the short direction have different lengths, and the second recesses adjacent in the short direction are offset in the long direction. A vehicle having a directional pattern embossed surface on the underside of its body in one embodiment of the present invention is a vehicle having a drivable body, wherein the body is provided with a front undercover member at the front of the underside of the body, the front undercover member having a two-tiered flat portion and a shape that slopes down in multiple stages from front to rear, and the rear flat portion of the two-tiered flat portion is formed with a directional pattern embossed surface that promotes airflow along the fore-and-aft direction of the body.

[0007] An undercover member for a vehicle body according to one aspect of the present invention is an undercover member provided on at least one of a front and a rear underside of a vehicle having a drivable body, the undercover member having a directional patterned grained surface formed on a flat surface portion of the undercover member to promote airflow along the longitudinal direction of the vehicle body. The embossed surface includes a plurality of ribs formed with a first recess in a short direction along the left-right direction of the vehicle body and a second recess in a long direction along the front-rear direction of the vehicle body, and the plurality of ribs adjacent in the short direction have different lengths, and the second recesses adjacent in the short direction are offset in the long direction. [Effects of the Invention]

[0008] In the present invention, an undercover member is provided on the underside of a body of a drivable vehicle at least at one of the front and rear portions of the underside of the body. The undercover member has a flat portion formed with a textured surface having a directional pattern that promotes airflow along the fore-and-aft direction of the vehicle body. By providing the flat portion of the undercover member that forms part of the underside of the vehicle body with the textured surface having a directional pattern that promotes airflow along the fore-and-aft direction of the vehicle body, the airflow flowing under the vehicle body is promoted to flow along the fore-and-aft direction of the vehicle body at least in the portion where the textured surface having the directional pattern is formed. Under the vehicle body, the flow along the fore-and-aft direction of the vehicle body can be made faster or increased compared to the flow in other directions, such as the vehicle width direction. In contrast, even if non-directional dimples for preventing peeling were formed on part of the underside of the vehicle body, it would be difficult to achieve the effect of prioritizing the flow along the fore-and-aft direction of the vehicle body over airflow in other directions, and it is unlikely that the deterioration of driving performance due to airflow below the vehicle body would be suppressed. The present invention can improve the airflow under the vehicle body by giving priority to the flow along the fore-and-aft direction of the vehicle body compared to the flow in other directions, which is expected to not only reduce air resistance but also improve driving performance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic side view of an automobile according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic bottom view of the automobile of FIG. [Figure 3] FIG. 3 is a schematic front view of a textured surface with a directional pattern that can promote airflow in one direction over intersecting airflow in another direction, which is provided on the underside of the automobile of FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along the line AA of the textured surface of the directional pattern of FIG. [Figure 5]FIG. 5 is an explanatory diagram of a front under-center panel having a textured surface with the directional pattern of FIGS. 3 and 4 and the airflow around the panel. [Figure 6] FIG. 6 is an explanatory diagram of a rear under-center panel having a textured surface with the directional pattern of FIGS. 3 and 4 and the airflow around the panel. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a schematic side view of an automobile 1 according to an embodiment of the present invention. FIG. 2 is a schematic bottom view of the automobile 1 of FIG. An automobile 1 is an example of a vehicle. The automobile 1 has a body 2. The body 2 has a passenger compartment 3 where passengers ride and sit. A pair of front wheels 4 are provided in front of the passenger compartment 3. A pair of rear wheels 5 are provided behind the passenger compartment 3.

[0012] The automobile 1 is manually operated by a passenger or automatically driven, and basically travels forward, changing its direction of travel to the right or left depending on the steering. The automobile 1 can also travel backward, rear right, or rear left. Air currents are generated around the traveling vehicle body 2. After hitting the front surface 6 of the vehicle body 2, the air in front of the vehicle body 2 in the traveling direction splits off to the sides, upper or lower of the vehicle body 2, and flows rearward along the side surfaces 7, upper surface 9, or lower surface 10 of the vehicle body 2. The split air currents merge at the rear of the vehicle body 2. At this time, at the rear of the vehicle body 2, for example, a portion of the air currents flowing along the left and right side surfaces 7 of the vehicle body 2 are entrained toward the rear surface 8 of the vehicle body 2, generating an entrained flow FL1. Furthermore, a portion of the air current flowing along the lower surface 10 of the vehicle body 2 is entrained toward the rear surface 8 of the vehicle body 2, generating an entrained flow FL5. These air currents create air resistance that hinders the traveling of the automobile 1.

[0013] For this reason, the automobile 1 is provided with a plurality of panels and covers that form the surface of the underside 10 of the vehicle body 2 as undercover members for rectifying the airflow around the vehicle body 2 and reducing air resistance. 2, the underside 10 of the automobile 1 is provided with a plurality of panels and covers, such as a front under-center panel 22, a left front under-side cover 23, a right front under-side cover 24, a left center under-side cover 25, a right center under-side cover 26, a rear under-center panel 29, a left rear under-side cover 27, and a right rear under-side cover 28. These panels and covers may be formed by injection molding or the like using a resin material.

[0014] The front under center panel 22 is provided in the front center portion of the underside 10 of the vehicle body 2. The front under center panel 22 is provided from the front edge of the front bumper 21 provided on the lower front part of the vehicle body 2 to between the pair of front wheels 4. The front under center panel 22 extends from the front bumper 21 to near the rear edge of the wheel housings for the pair of front wheels 4. A pair of mufflers 61 are exposed on the underside 10 of the vehicle body 2 behind the front under center panel 22. The pair of mufflers 61 pass through the center portion of the underside 10 of the vehicle body 2, and their rear ends reach the rear bumper 30 at the lower rear surface of the vehicle body 2.

[0015] The left front underside cover 23 is provided at the left front corner of the underside 10 of the vehicle body 2. The left front underside cover 23 is provided on the left side of the front undercenter panel 22, extending from the front undercenter panel 22 to the left side surface 7 of the vehicle body 2. A wheel house for the left front wheel 4 is located behind the left front underside cover 23.

[0016] The right front underside cover 24 is provided at the right front corner of the underside 10 of the vehicle body 2. The right front underside cover 24 is provided on the right side of the front undercenter panel 22, extending from the front undercenter panel 22 to the right side surface 7 of the vehicle body 2. A wheel house for the right front wheel 4 is located behind the right front underside cover 24.

[0017] The left center underside cover 25 is provided along the left edge of the left side surface 7 on the underside 10 of the vehicle body 2, in the section from the wheelhouse for the left front wheel 4 to the wheelhouse for the left rear wheel 5. A left muffler 61 is located on the center side of the left center underside cover 25 in the vehicle width direction, which is the left-right direction of the vehicle body 2.

[0018] The right center underside cover 26 is provided on the underside 10 of the vehicle body 2 along the right edge of the right side surface 7, in the section from the wheelhouse for the right front wheel 4 to the wheelhouse for the right rear wheel 5. A right muffler 61 is located on the center side of the right center underside cover 26 in the vehicle width direction.

[0019] The left rear underside cover 27 is provided at the left rear corner of the underside 10 of the vehicle body 2. The left rear underside cover 27 is provided in front of the rear bumper 30 provided on the lower rear surface of the vehicle body 2, from the left muffler 61 to the left side surface 7 of the vehicle body 2. A wheel house for the left rear wheel 5 is located in front of the left rear underside cover 27.

[0020] The right rear underside cover 28 is provided at the right rear corner of the underside 10 of the vehicle body 2. The right rear underside cover 28 is provided in front of the rear bumper 30 provided on the lower rear surface of the vehicle body 2, from the right muffler 61 to the right side surface 7 of the vehicle body 2. A wheel house for the right rear wheel 5 is located in front of the right rear underside cover 28.

[0021] The rear under center panel 29 is provided between the left rear under side cover 27 and the right rear under side cover 28. The rear under center panel 29 is provided from a position between the rear wheels 5 to the rear edge of the rear bumper 30 provided on the lower rear surface of the vehicle body 2. The rear end portions of a pair of mufflers 61 are covered by the rear under center panel 29.

[0022] These multiple panels and covers make the underside 10 of the automobile 1 a generally flat surface. This allows the airflow flowing under the automobile 1 to flow smoothly from front to rear along the generally flat underside 10 of the automobile 1 and be discharged from the rear of the automobile 1. However, for example, a pair of front wheels 4 and a pair of rear wheels 5 protrude downward from the underside 10 of the vehicle body 2. The underside 10 of the vehicle body 2 often has an overall convex shape with the central portion lower than the front and rear portions. Due to these factors, part of the airflow flowing under the vehicle 1 is prevented from flowing rearward. As a result, part of the airflow that has flowed under the vehicle 1 may become airflows FL2 and FL3 that blow out from the underside of the vehicle body 2 toward the outside in the vehicle width direction. When airflows FL2 and FL3 blow out from the underside of the vehicle body 2 toward the outside in the vehicle width direction, these blown-out airflows may merge with the airflow flowing along the side surface 7 of the vehicle body 2, disrupting the flow along the side surface 7 of the vehicle body 2.

[0023] For this reason, in this embodiment, a directional patterned textured surface 40 capable of promoting airflow in the longitudinal direction is formed on some of the panels and covers constituting the underside 10 of the vehicle body 2. This is expected to increase the rearward flow velocity and volume of the airflow under the vehicle body 2, strengthening the rearward flow. It is also expected to reduce the amount of airflows FL2 and FL3 that are blown outward in the vehicle width direction from the underside of the vehicle body 2. Moreover, the directional pattern textured surface 40 is not formed on the entire underside 10 of the vehicle body 2, but only on the front and rear portions of the underside 10. In particular, the directional pattern textured surface 40 of this embodiment is formed only on the flat portions, excluding the uneven portions of the panels and covers that make up the underside 10 of the vehicle body 2. The flat portions are preferably parallel to the road surface, but this is not a limitation. This can result in a difference in the longitudinal flow velocity of the airflow beneath the underside 10 of the vehicle body 2 between the central portion and both sides in the vehicle width direction. The balance of the airflow on the underside 10 of the vehicle body 2 differs from that on the underside 10 of the vehicle body 2 that does not have the directional pattern textured surface 40. The airflow on both sides in the vehicle width direction is more likely to be drawn into the airflow in the central portion. This makes it possible to optimize or improve the airflow along the underside 10 of the vehicle body 2 of a moving automobile 1. For example, it may be possible to effectively reduce the amounts of airflows FL2 and FL3 that blow out from the underside of the vehicle body 2 toward the outside in the vehicle width direction.

[0024] FIG. 3 is a schematic front view of a directional patterned textured surface 40 provided on the underside 10 of the automobile 1 of FIG. 1, which can promote airflow in one direction over intersecting airflow in another direction. FIG. 4 is a schematic cross-sectional view taken along line AA of the textured surface 40 of the directional pattern of FIG. The directional patterned grained surface 40 of FIGS. 3 and 4 has a base surface 41 and a plurality of minute rib portions 42 formed to protrude from the base surface 41.

[0025] The textured surface 40 may be formed simultaneously when molding a panel or cover to be provided on the underside 10 of the automobile 1. The base surface 41 may be a sheet to be attached to the outer surface of the panel or cover to be provided on the underside 10 of the automobile 1.

[0026] The base surface 41 is the outer surface of the panel or cover on which the directional patterned grained surface 40 is provided. The base surface 41 is basically flat, but is not necessarily limited to this.

[0027] The plurality of rib portions 42 include elongated rib portions 42. The elongated rib portion 42 has an oblong shape with both ends in the longitudinal direction rounded. The elongated rib portion 42 may have a cubic shape with a rectangular cross section, for example. The protruding height of the rib portion 42 from the base surface 41 may be, for example, several micrometers or more.

[0028] The multiple rib portions 42 are formed across the entire base surface 41, aligned linearly in the longitudinal direction of the elongated rib portion 42. The multiple rib portions 42 are aligned in multiple rows in the lateral direction of the elongated rib portion 42. First recesses 43 are formed as minute gaps between the multiple rib portions 42 adjacent to each other in the lateral direction. The first recesses 43 are formed across the entire base surface 41, extending linearly along the longitudinal direction of the elongated rib portion 42, forming continuous linear gaps.

[0029] The plurality of rib portions 42 may include rib portions having lengths different from the elongated shape, such as a regular cube shape or a cylindrical shape. 3, a plurality of rib portions 42 having different lengths in the short direction of the elongated rib portion 42 are arranged in a diamond-shaped arrangement pattern. The plurality of diamond-shaped arrangement patterns are arranged densely on the base surface 41. By arranging in this manner, second recesses 44 are formed as minute gaps between the plurality of rib portions 42 adjacent to each other in the longitudinal direction. The second recesses 44 formed in each row are shifted in the longitudinal direction from the second recesses 44 formed in the adjacent rows.

[0030] In the textured surface 40 having such a surface structure, airflow can occur along the longitudinal direction, as shown by the dotted line in FIG. 4, minute vortices are generated between the textured surface 40 and the airflow near the surface of the textured surface 40 due to the effect of the linearly extending first recesses 43, etc. The generation of minute vortices allows the airflow along the longitudinal direction of the textured surface 40 to flow efficiently near the surface of the textured surface 40 at a high flow rate. 3, for example, airflow along the short side direction, minute vortices are not generated on the textured surface 40 due to the effect that the second recesses 44 do not extend linearly on the textured surface 40. As a result, the airflow along the short side direction is less likely to flow, as it is drawn closer to the surface of the textured surface 40. Friction occurs between the airflow along the short side direction and the textured surface 40, and the flow velocity is less likely to increase. As such, the textured surface 40 with the surface structure shown in Figures 3 and 4 can efficiently flow airflow along the longitudinal direction at a higher flow rate than airflow along the lateral direction. The textured surface 40 with the directional pattern shown in Figures 3 and 4 has a directional property such that airflow along its surface is more easily passed in one direction (the longitudinal direction) than in the other direction (the lateral direction). The textured surface 40 shown in Figures 3 and 4 functions as a directional pattern that promotes airflow along the longitudinal direction.

[0031] The surface structure of a member constituting a surface such as the underside 10 of the vehicle body 2 may have a base surface 41 with multiple protrusions of the same shape, or multiple recesses (dimples) of the same shape, instead of the textured surface 40 shown in Figures 3 and 4. However, with these surface structures, it is extremely difficult to achieve a directionality that makes it easier for the material to flow in one direction than in another. The shapes of the protrusions and recesses (dimples) here may be, for example, hexagonal or partially spherical.

[0032] The directional pattern embossed surface 40 shown in Figures 3 and 4 is formed on some of the multiple panels and covers that make up the underside 10 of the vehicle body 2 so that the longitudinal direction of the elongated rib portion 42 is the fore-and-aft direction of the vehicle body 2, in order to promote airflow in the fore-and-aft direction of the vehicle body 2. In this case, the multiple rib portions 42 are formed side by side in the longitudinal direction and the vehicle width direction of the vehicle body 2. Furthermore, between the multiple rib portions 42 lined up in the vehicle width direction of the vehicle body 2, multiple continuous linear gaps that are continuous in a straight line along the longitudinal direction of the vehicle body 2 are formed by the multiple first recesses 43 over the entire directional pattern textured surface 40. Furthermore, two second recesses 44 that are lined up adjacent to each other in the vehicle width direction are formed offset in the longitudinal direction of the vehicle body 2.

[0033] 2 of this embodiment, the directional pattern textured surface 40 is provided on some of the panels and covers provided on the underside 10 of the automobile 1, such as the front under center panel 22, the rear under center panel 29, the left rear under side cover 27, and the right rear under side cover 28. In this embodiment, the directional pattern textured surface 40 is not formed on the left front under side cover 23, the right front under side cover 24, the left center under side cover 25, and the right center under side cover 26.

[0034] In the front under center panel 22, which is provided in the range from the leading edge of the vehicle body 2 to the front wheels 4, the directional pattern textured surface 40 is formed in a symmetrical range on the flat portion of the front under center panel 22, with the center of the vehicle in the vehicle width direction as the reference point. Here, the flat portion may be, for example, a flat portion of the front under center panel 22 that is parallel to a flat road surface. In addition, the left front under side cover 23 and the right front under side cover 24, which are provided in the vehicle width direction of the front under center panel 22, do not have the directional pattern textured surface 40 formed thereon. The directional patterned grained surface 40 is formed on the underside 10 of the vehicle body 2 in a portion forward of the front wheels 4, in a central area excluding both left and right end portions in the vehicle width direction.

[0035] Furthermore, on the rear under center panel 29 provided in the range from the rear edge of the vehicle body 2 to the rear wheels 5, the directional pattern textured surface 40 is formed in a left-right symmetrical range with respect to the center of the vehicle body in the vehicle width direction on the flat surface portion of the rear under center panel 29. In addition, on the flat surface portion of the left rear under side cover 27 and the flat surface portion of the right rear under side cover 28 provided in the vehicle width direction of the rear under center panel 29, the directional pattern textured surface 40 is also formed in a left-right symmetrical range on the vehicle body 2. The directional pattern textured surface 40 is formed on the underside 10 of the vehicle body 2 in the area rearward of the rear wheels 5, covering the entire range of both left and right end portions and the central portion in the vehicle width direction. The directional pattern textured surface 40 is formed in an area including the rear portion of the rear wheels 5. On the underside 10 of the vehicle body 2, the embossed surface 40 of the rear directional pattern is formed in an area wider in the vehicle width direction than the embossed surface 40 of the front directional pattern.

[0036] In this case, the airflow that flows into the underside 10 of the vehicle body 2 is promoted to flow in the longitudinal direction, which is the direction of travel, at the center of the underside 10 of the vehicle body 2 in the vehicle width direction, as shown by the bold line in the airflow at the underside 10 of the vehicle body 2 in Figure 2. This fast and large volume of airflow at the center of the vehicle width direction can draw in airflow on both sides. As a result, the airflow in the longitudinal direction, which is the direction of travel, is also promoted at the left front corner, right front corner, left rear corner, and right rear corner. The airflow balance at the underside 10 of the vehicle body 2 is different from that when the directional patterned grained surface 40 is not provided.

[0037] Figure 5 is an explanatory diagram of the front under-center panel 22 having the directional patterned textured surface 40 of Figures 3 and 4 and the airflow around it. Figure 5 shows an end face at the center in the vehicle width direction for the portion of the vehicle body 2 that is forward of the front wheels 4. The front under-center panel 22 in Figure 5 extends rearward from the lower end of the front bumper 21. The front under-center panel 22 has two-tiered flat portions 221, 222. A directional patterned textured surface 40 is formed over substantially the entire rear flat portion 222. The longitudinal direction of the elongated rib portions 42 of the directional patterned textured surface 40 is aligned with the front-to-rear direction. When using a front under center panel 22 that is shaped to descend in multiple steps from the front bumper 21 in this way, the distance between the underside 10 of the vehicle body 2 and the road surface becomes narrower toward the rear of the vehicle body 2. Airflow that enters from the front of the vehicle body 2 and under the vehicle body 2 tends to stagnate near the flat surface 221 on the front side of the front under-center panel 22 from the front bumper 21. When airflow stagnates, the air pressure in that area tends to increase.

[0038] In this embodiment, a directional patterned textured surface 40 that promotes airflow in the longitudinal direction is formed on the rear flat surface 222 of the front under center panel 22, which is behind the stagnation portion. The directional patterned textured surface 40 increases the speed and volume of airflow along the rear flat surface 222 of the front under center panel 22. By increasing the speed and volume of airflow passing between the rear flat surface 222 of the front under center panel 22 and the road surface, a force that pulls down the rear flat surface 222 is more likely to act on it. Furthermore, when the air flow velocity between the rear flat surface 222 of the front under center panel 22 and the road surface increases and the air pressure decreases, it becomes easier to draw in the air in front of it. Airflow is efficiently drawn from the stagnant area near the front flat surface 221 of the front under center panel 22 from the front bumper 21. When the amount of air stagnating in the stagnant area decreases, the force that tends to push up the front under center panel 22 and other components due to the pressure in the stagnant area is reduced. Furthermore, the amount of air that tends to flow from the stagnant area, for example, outward in the vehicle width direction (perpendicular to the plane of the paper), can be reduced. As a result, the force pushing up the portion of the vehicle body 2 in front of the front wheels 4 is reduced, making the front portion of the vehicle body 2 less likely to lift, making it less likely that the grip performance of the front wheels 4 will decrease, and making it less likely that the steering response of the automobile 1 will be impaired. Reduction in downforce is suppressed. This can improve ground contact feel and steering response. Furthermore, a portion of the airflow heading toward the front wheel 4 below the left front underside cover 23 is likely to be drawn toward the front under center panel 22 after hitting the front wheel 4. A portion of the airflow heading toward the front wheel 4 below the right front underside cover 24 is likely to be drawn toward the front under center panel 22 after hitting the front wheel 4. This is expected to reduce the amount of airflow that tends to flow outward in the vehicle width direction after hitting the front wheel 4.

[0039] Fig. 6 is an explanatory diagram of the rear under center panel 29 having the directional pattern textured surface 40 of Fig. 3 and Fig. 4 and the airflow around it. Fig. 6 shows the end face at the center in the vehicle width direction of the portion of the vehicle body 2 that is rearward of the rear wheels 5. The end faces of the left rear under side cover 27 and the right rear under side cover 28 may also be similar to Fig. 6. The rear under center panel 29 in Figure 6 extends from the lower end of the rear bumper 30 to the wheel housing of the rear wheel 5 (not shown). The rear under center panel 29 has a flat surface 291 that slopes upward toward the rear. A directional pattern textured surface 40 is formed over substantially the entire flat surface 291. The longitudinal direction of the elongated rib portion 42 of the directional pattern textured surface 40 is aligned with the front-to-rear direction. When using a rear under center panel 29 having a flat surface 291 that slopes upward toward the rear in this manner, the distance between the underside 10 of the vehicle body 2 and the road surface becomes slightly wider toward the rear of the vehicle body 2. Basically, the air between the rear under center panel 29 and the road surface tends to escape rearward. The airflow that enters under the vehicle body 2 flows in the fore-and-aft direction and flows out toward the rear of the vehicle body 2. Furthermore, the directional pattern textured surface 40 is formed not only on the rear under center panel 29, but also on the left rear under side cover 27 and the right rear under side cover 28. At the rear portion of the underside 10 of the vehicle body 2, the directional pattern textured surface 40 is formed over the entire vehicle width direction. As a result, an airflow that flows entirely toward the rear of the vehicle body 2 in the vehicle width direction blows out from the rear portion of the vehicle body 2, making it difficult for the entire vehicle to lift up in the vehicle width direction. Furthermore, part of the airflow under the vehicle body 2 is blocked by the rear wheels 5 in the wheelhouses of the rear wheels 5 and is then more likely to be drawn toward the rear under center panel 29. This is expected to reduce the amount of airflow that tends to flow outward in the vehicle width direction after hitting the rear wheels 5. Furthermore, part of the airflow that flows outward in the vehicle width direction is more likely to return under the left rear under side cover 27 or the right rear under side cover 28.

[0040] In this embodiment, a textured surface 40 with a directional pattern that promotes airflow in the front-to-rear direction is formed on the flat surface 291 of the rear under center panel 29. The same is true for the end surface of the left rear under side cover 27 and the end surface of the right rear under side cover 28. In this way, the textured surface 40 with a directional pattern is formed over the entire rear portion of the underside 10 of the vehicle body 2 in the vehicle width direction. Due to the textured surface 40 with a directional pattern, the airflow that blows rearward from the rear portion of the underside 10 of the vehicle body 2 becomes an airflow in the front-to-rear direction, increasing the flow velocity and volume. A force that pulls down the entire rear portion of the underside 10 of the vehicle body 2 is more likely to act on it. Furthermore, when the air flow velocity increases between the flat surface 291 of the rear under-center panel 29 and the road surface and the air pressure decreases, the air in front of it is more likely to be drawn in. Even if the airflow tends to stagnate forward of the rear part of the underside 10 of the vehicle body 2, the stagnant portion efficiently draws in the air, reducing the amount of stagnant air. Furthermore, part of the airflow that tends to move outward in the vehicle width direction after hitting the rear wheels 5 is more likely to be drawn toward the center of the vehicle body 2 in the vehicle width direction. As a result, the rear portion of the vehicle body 2 behind the rear wheels 5 is less likely to lift up, the grip performance of the rear wheels 5 is less likely to decrease, and the straight-line stability of the automobile 1 is less likely to be impaired. Reduction in downforce is suppressed. Ground contact feel and steering responsiveness can be improved.

[0041] As described above, in this embodiment, the body 2 of a drivable automobile 1 is provided with an undercover member made of a panel or cover that forms part of the underside 10 of the body 2, and a directional patterned embossed surface 40 is formed on the flat portion of a part of the undercover member to promote airflow along the fore-and-aft direction of the body 2. In this embodiment, an undercover member is provided on the underside 10 of a vehicle body 2 of a drivable automobile 1 at the front and rear of the underside 10 of the vehicle body 2. The undercover member has a flat surface formed with a directional pattern textured surface 40 that promotes airflow along the longitudinal direction of the vehicle body 2. By providing the flat surface of the undercover member, which is part of the underside 10 of the vehicle body 2, with the directional pattern textured surface 40 that promotes airflow along the longitudinal direction of the vehicle body 2, the airflow flowing under the vehicle body 2 is promoted along the longitudinal direction of the vehicle body 2, at least in the portion where the directional pattern textured surface 40 is formed. Under the vehicle body 2, the airflow along the longitudinal direction of the vehicle body 2 can be made faster or increased compared to the airflow in other directions, such as the width direction of the vehicle. In this embodiment, the airflow under the vehicle body 2 can be made different from the general case in which the underside 10 of the vehicle body 2 does not have a directional pattern textured surface 40. In contrast, even if non-directional dimples for preventing peeling were formed on a part of the underside 10 of the vehicle body 2, it would be difficult to obtain the effect of prioritizing the flow along the fore-and-aft direction of the vehicle body 2 over airflow in other directions, and it is unlikely that the deterioration of driving performance due to airflow on the underside of the vehicle body 2 would be suppressed. In this embodiment, the airflow below the vehicle body 2 can be prioritized in the fore-and-aft direction of the vehicle body 2 compared to flows in other directions, which is expected to not only reduce air resistance but also improve driving performance. In this embodiment, the aerodynamics can be improved and driving performance such as steering response and straight-line stability can be improved by providing a directional pattern textured surface 40 on the surface of a resin member without changing the exterior design of the automobile 1 or the structure of the vehicle body 2 or adding large aerodynamic parts. In particular, by providing a directional pattern textured surface 40 on both the front and rear portions of the underside 10 of the vehicle body 2, a strong, uniform airflow in the longitudinal direction is more likely to be generated under the vehicle body 2 from the front to the rear of the vehicle body 2.

[0042] In particular, in this embodiment, in the front portion of the underside 10 of the vehicle body 2, from the leading edge of the vehicle body 2 to the front wheels 4, a directional pattern textured surface 40 is formed on the flat portion 222 of the front under center panel 22. As a result, the directional pattern textured surface 40 in the front portion of the vehicle body 2 includes the center of the vehicle body 2 in the vehicle width direction and is provided in an area symmetrical with respect to the center of the vehicle body 2 in the vehicle width direction. The directional pattern textured surface 40 is formed in an area excluding the front portion of the front wheels 4. As a result, the airflow in the front portion of the underside 10 of the vehicle body 2 can be efficiently directed rearward from between the front wheels 4, improving the steering response of the automobile 1.

[0043] Furthermore, in this embodiment, in the rear portion of the underside 10 of the vehicle body 2 from the rear edge of the vehicle body 2 to the rear wheels 5, the rear under center panel 29, the left rear under side cover 27, and the right rear under side cover 28 are formed with a directional pattern textured surface 40. As a result, the directional pattern textured surface 40 in the rear portion of the vehicle body 2 includes the center in the vehicle width direction of the vehicle body 2 and is provided over an overall and symmetrical range in the vehicle width direction of the vehicle body 2. As a result, the airflow at the rear portion of the underside 10 of the vehicle body 2 can be efficiently directed rearward from the underside of the vehicle body 2, thereby improving the straight-line stability of the automobile 1.

[0044] As shown in FIG. 1, the front bumper 21 provided from the front face 6 to the side face 7 of the vehicle body 2 has specially processed surfaces 51 on the surfaces of the left and right side faces. The specially processed surface 51 may be provided with a textured surface 40 having a directional pattern similar to that shown in Figures 3 and 4, with its longitudinal direction aligned with the front-to-rear direction. The specially processed surface 51 may be provided with a textured surface 40 having a directional pattern similar to that shown in Figures 3 and 4, with its longitudinal direction inclined upward toward the rear relative to the front-to-rear direction. The surface of the side portion of the front bumper 21, which is provided from the front surface 6 to the side surface 7 of the vehicle body 2, is provided with a textured surface 40 having a directional pattern that facilitates airflow in one direction (front-to-rear direction) along the surface.

[0045] In this way, the left and right side surfaces of the front bumper 21 of the vehicle body 2 are formed with a textured surface 40 having a directional pattern that basically follows the longitudinal direction. As a result, the airflow that hits the front surface 6 of the vehicle body 2 flows along the front surface 6 of the vehicle body 2 toward the front corners, and then is prevented from separating from the surface of the vehicle body 2 at the front corners of the vehicle body 2, and is made to flow easily along the side surfaces 7 of the vehicle body 2. The specially textured surface 51 on the rear side of the front corners of the vehicle body 2 increases the flow velocity, thereby preventing the airflow flowing from the front surface 6 to the side surfaces 7 of the vehicle body 2 from separating from the surface of the vehicle body 2 at the front corners of the vehicle body 2. The left and right front underside covers 23, 24 are formed with directional patterned textured surfaces 40. This reduces the airflow that flows outward in the vehicle width direction from the underside of the front underside covers. The airflow that flows along the side surface 7 of the vehicle body 2 without separating from the side surface 7 of the vehicle body 2 is less likely to be disturbed by the airflow that blows out from the underside of the front underside covers 23, 24. The airflow that flows along the side surface 7 of the vehicle body 2 is more likely to flow along the side surface 7 of the vehicle body 2 around the front wheels 4 and behind them.

[0046] By providing both the directional pattern textured surface 40 on the side surface of the front bumper 21 and the directional pattern textured surface 40 on the front portion of the underside 10 of the vehicle body 2, the airflow hitting the front surface 6 of the vehicle body is easily divided and flows efficiently and in a balanced manner toward both the underside 10 side and the side surfaces 7, 7 of the vehicle body 2. This can reduce the amount of airflow that is compressed or stagnated in front of the vehicle body. In contrast, if the directional pattern textured surface 40 were not formed on the side portion of the front bumper 21, the airflow hitting the front surface 6 of the vehicle body would likely flow more toward the underside 10 of the vehicle body 2 than toward the side surfaces 7, 7 of the vehicle body 2. If the amount of airflow flowing under the vehicle body 2 increases, the lifting effect of the front portion of the vehicle body would increase, and even if the directional pattern textured surface 40 on the front portion of the underside 10 of the vehicle body 2 described above is used to efficiently direct the airflow rearward, there is a possibility that the effect of improving the steering response of the automobile 1 would be reduced. In this embodiment, such a situation is less likely to occur. In this embodiment, the directional pattern textured surface 40 is formed in areas symmetrical with respect to the center of the vehicle width direction of the vehicle body 2 on the undercovers 29, 27, 28 provided in the range from the rear edge of the vehicle body 2 to the rear wheels 5 provided on the vehicle body 2. This increases the airflow at the rear portion of the underside 10 of the vehicle body 2 and allows it to flow efficiently rearward, improving the straight-line stability of the automobile 1. In particular, because the directional pattern textured surface 40 is formed in a range that includes the rear portions of the rear wheels 5, it is possible to efficiently increase the airflow flowing from the underside of the vehicle body 2 toward the rear, which tends to enhance the effect of improving the straight-line stability of the automobile 1.

[0047] The above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications and changes are possible within the scope of the gist of the invention.

[0048] In the above-described embodiment, the undercovers 29, 27, 28 provided at the rear of the underside 10 of the vehicle body 2 all have the directional patterned grained surface 40 formed in a target range based on the center in the vehicle width direction. Alternatively, for example, the directional pattern textured surface 40 on the rear of the underside 10 of the vehicle body 2 may be formed in a target range based on the center in the vehicle width direction only on the rear under-center panel 29 of the under-covers 29, 27, 28. In this case, however, the directional pattern textured surface 40 does not have the effect of rectifying the airflow in the front-to-rear direction at both ends in the vehicle width direction of the rear of the underside 10 of the vehicle body 2, and therefore may be less effective in suppressing lifting of the rear of the vehicle body 2. By forming the directional pattern textured surface 40 on all of the under-covers 29, 27, 28, it is possible to effectively suppress lifting of the rear of the vehicle body 2 and obtain high straight-line stability.

[0049] In the above-described embodiment, a directional pattern embossed surface 40 is formed only on the front under center panel 22 provided at the front part of the underside 10 of the vehicle body 2, in a target range based on the center in the vehicle width direction. Alternatively, for example, the directional pattern textured surface 40 on the front portion of the underside 10 of the vehicle body 2 may be formed in a target range with respect to the center in the vehicle width direction on all of the under-covers 22, 24, and 25. However, in this case, the airflow under the vehicle body 2 may be more likely to flow in the fore-and-aft direction even in front of the front wheels 4, which may reduce the effect of drawing part of the airflow toward the center in the vehicle width direction of the vehicle body 2. By deliberately not forming the directional pattern textured surface 40 on the under-covers 24 and 25 as in the above-described embodiment, it is believed that the effect of directing the airflow flowing under the vehicle body 2 rearward through the spaces between the multiple front wheels 4 is enhanced.

[0050] In the above-described embodiment, the grained surface 40 having a directional pattern is formed on the front and rear portions of the underside 10 of the vehicle body 2. Alternatively, for example, the grained surface 40 having a directional pattern may be formed on only one of the front and rear portions of the underside 10 of the vehicle body 2. However, by forming the directional pattern textured surface 40 in the target range, based on the center in the vehicle width direction, on both the front and rear portions of the underside 10 of the vehicle body 2, the airflow flowing under the vehicle body 2 can easily flow from the front portion of the vehicle body 2 through the center portion to the rear portion. In this embodiment, even if the leading and trailing edges of the vehicle body 2 are inclined away from the road surface compared to the center portion, as shown in FIGS. 5 and 6, the airflow that has flowed under the vehicle body 2 can flow smoothly in the fore-and-aft direction under the vehicle body 2 and exit rearward from the rear edge of the vehicle body 2. Furthermore, an undercover member having the directional pattern textured surface 40 formed thereon may be provided in the fore-and-aft center portion of the vehicle body 2, just like the front and rear portions of the vehicle body 2. However, in this embodiment, a smooth airflow can be achieved over the entire underside of the vehicle body 2 without using such a member. [Explanation of symbols]

[0051] 1...automobile (vehicle), 2...vehicle body, 3...passenger compartment, 4...front wheels, 5...rear wheels, 6...front surface, 7...side, 8...rear surface, 9...upper surface, 10...lower surface, 21...front bumper, 22...front under center panel, 23...left front under side cover, 24...right front under side cover, 25...left center under side cover, 26...right center under side cover, 27...left rear under side cover, 28...right rear under side cover, 29...rear under center panel, 30...rear bumper, 40...directional pattern textured surface, 41...base surface, 42...rib portion, 43...first recess, 44...second recess, 51...specially processed surface, 61...muffler, 221, 222, 291...flat portion

Claims

1. A vehicle having a drivable body, The vehicle body is provided with an undercover member at least at one of a front portion and a rear portion of a lower surface of the vehicle body, A directional patterned embossed surface that promotes airflow along the front-rear direction of the vehicle body is formed on a flat surface of the under-cover member, The textured surface includes a plurality of ribs formed with a first recess in a lateral direction along the left-right direction of the vehicle body and a second recess in a longitudinal direction along the front-rear direction of the vehicle body, and the plurality of ribs adjacent to each other in the lateral direction have different lengths, and the second recesses adjacent to each other in the lateral direction are offset from each other in the longitudinal direction. A vehicle having a directional patterned grained surface on the underside of the body.

2. the under-cover member is a front under-member provided in a center portion of the underside of the vehicle body in a vehicle width direction in a front portion from a leading edge of the vehicle body to a front wheel provided on the vehicle body, The embossed surface of the directional pattern is provided in a range including the center of the vehicle body in the vehicle width direction on a planar portion of the front under member.

2. A vehicle according to claim 1, wherein the underside of the vehicle body has a textured surface with a directional pattern.

3. the under-cover member is a rear under-member provided on at least a central portion of the underside of the vehicle body in a vehicle width direction in a rear portion from a rear edge of the vehicle body to a rear wheel provided on the vehicle body, The embossed surface of the directional pattern is provided on a planar portion of the rear under member in a range including at least the center of the vehicle body in a vehicle width direction.

3. A vehicle having a directional patterned embossed surface on the underside of the vehicle body according to claim 1.

4. a front bumper member provided from the front surface to the side surfaces of the vehicle body; The surface of the side surface of the front bumper member is formed with a directional patterned embossed surface that facilitates airflow in one direction along the surface.

4. A vehicle having a directional pattern textured surface on the underside of the vehicle body according to claim 1.

5. An undercover member provided on at least one of a front portion and a rear portion of an underside of a vehicle having a drivable body, A directional patterned embossed surface that promotes airflow along the front-rear direction of the vehicle body is formed on a flat surface of the under-cover member, The textured surface includes a plurality of ribs formed with a first recess in a lateral direction along the left-right direction of the vehicle body and a second recess in a longitudinal direction along the front-rear direction of the vehicle body, and the plurality of ribs adjacent to each other in the lateral direction have different lengths, and the second recesses adjacent to each other in the lateral direction are offset from each other in the longitudinal direction. Underbody cover material.

6. A vehicle having a drivable body, The vehicle body is provided with a front undercover member at a front portion of a lower surface of the vehicle body, the front under-cover member has a shape that has two flat portions and descends in multiple steps from front to rear, The rear flat portion of the two-stage flat portion is formed with a textured surface having a directional pattern that promotes airflow along the front-rear direction of the vehicle body. A vehicle having a directional patterned grained surface on the underside of the body.

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