JP3085156B2 - Undercover for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an undercover which covers a lower part of an engine room of a vehicle.

[0002]

2. Description of the Related Art A conventional undercover for a vehicle is generally flat as shown in Japanese Utility Model Laid-Open No. 4-95575, and is disposed higher than a guide plate and an undercover connected to a trailing edge. The scoop that is conducted guides the wind flowing along the lower surface of the undercover to the transmission in the engine room and cools them intensively, but depending on the shape of the undercover, a sufficient amount of running may not be possible. Wind could not always be taken into the engine compartment.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to surely guide a traveling wind from below a vehicle under cover into an engine room above the vehicle, and to ensure a cooling function of devices arranged in the engine room. It is in.

[0004]

Therefore, a vehicle undercover according to the present invention is mounted on a vehicle body so as to cover a lower portion of an engine room, and has a substantially horizontal front portion and an upper portion extending from a rear end of the front portion. A vertical wall portion extending substantially horizontally rearward from an upper end of the vertical wall portion, an inclined portion extending rearward and downward from a rear end of the flat portion, and the engine room formed on the inclined portion. It has a ventilation opening to

That is, in an undercover attached to a vehicle body so as to cover a lower portion of an engine room, a vertical wall portion extends upward from a substantially horizontal front rear end, and a flat portion extends rearward from an upper end of the vertical wall portion. Because it extends almost horizontally,
When the vehicle travels, a vortex is generated along the lower surface of the flat portion by the traveling wind flowing backward from the vertical wall portion, and the lift acting on the front portion of the vehicle can be reduced by the negative pressure action of the vortex, while the flat portion is reduced. The inclined part extends from the rear end to the rear lower part, and when the traveling wind flows along the lower surface of the inclined part, the wind pressure is recovered, so that the vehicle can be reliably driven into the engine room from the air guide port formed in the inclined part. Wind can be introduced.

[0006]

Embodiments of the present invention will be described below. 1 to 5, an undercover 2 attached to a vehicle body so as to cover a lower part of an engine room 1 of a vehicle includes a substantially horizontal front portion 3 and a substantially V-shaped vertical wall portion 4 with respect to the front portion 3. A flat portion 5 having a substantially triangular shape and a substantially triangular flat portion 5 extending substantially horizontally rearward, and an inclined portion 6 gently tilting rearward and downward from the rear end of the flat portion 5. Is partially depressed upward to form an air guide passage 7 having a gate-shaped cross section as shown in FIG. 5, and a rear end of the air guide passage 7 has an air guide opening 8 into the engine room 1. An oil pan 9 for the transmission is arranged behind the wind guide port 8.

Here, the traveling wind at the above-mentioned stepped portion on the lower surface of the vehicle will be described with reference to FIG. 6. The traveling wind flowing along the flat surface 10 from the front, as shown by the arrows, Due to the presence of the step portion 11 at a distance d, a vortex 12 is generated away from the wall surface, and a negative pressure due to the vortex 12 acts on the flat surface 13 connected to the step portion 11, and the horizontal distance x from the step portion 11 At point a, the traveling wind starts to contact the flat surface 13 and thereafter flows backward along the flat surface 13.

In this case, the horizontal distance x from the step 11 to the point a tends to increase as the speed of the vehicle increases.
Further, between the vertical distance d of the step portion 11 and the horizontal distance x, the relationship shown in FIG. 7 is observed when the vehicle is traveling at a high speed of 100 km / h or more, and d / x ≒ 1/6 to 1/7. You can see that.

From the above, as shown in FIG. 4, the air guide path 7 formed in the inclined portion 6 of the under cover 2
Is set so that the horizontal distance X from the vertical wall portion 4 to the starting point A of the inclined portion 6 is about 6 to 7 times the vertical distance D of the vertical wall portion 4, or slightly larger than that.

Therefore, as indicated by the arrows in FIGS. 3 and 4, the traveling wind of the vehicle flowing backward along the lower surface of the undercover front portion 3 is reduced by the presence of the vertical wall portion 4 at a vertical distance D. Generates a vortex 20 away from the wall of
For this reason, the negative pressure due to the vortex 20 acts on the substantially V-shaped portion of the flat portion 5 whose width from the substantially V-shaped vertical wall portion 4 to the rear is substantially X, and acts on the front portion of the vehicle during traveling. Lift can be reduced by the under cover 2.

When the vehicle is separated from the V-shaped vertical wall portion 4 by a horizontal distance X rearward, the traveling wind flows rearward along the flat portion 5 or the inclined portion 6 as shown by arrows in FIGS. At this time, the negative pressure effect by the vortex 20 disappears, but the pressure is sufficiently recovered particularly when flowing backward and downward along the inclined portion 6, so that the pressure is horizontally restored rearward from the vertical wall portion 4. A part of the traveling wind is positively taken into the air guide path 7 of the inclined portion 6 separated by a distance X or more, and is blown from the rear air guide port 8 to the oil pan 9 of the transmission arranged rearward. Thus, the internal transmission oil can be efficiently cooled.

As described above, if the inclined portion 6 is separated from the vertical wall portion 4 by more than the horizontal distance X which is about 6 to 7 times the vertical wall portion vertical distance D, the subsequent inclined portion 6 Due to the gentle incline of the rearward and downward direction, the recovery of the pressure at the inclined portion 6 does not have any particular effect on the generation of the vortex 20, and therefore the lift acting on the front portion of the traveling vehicle is reduced. As a result, a stable running of the vehicle can be ensured, and at the same time, the running wind smoothly flows rearward along the inclined portion 6, and the under cover 2 is provided below the engine room 1.
Even if the vehicle is mounted, a part of the traveling wind is surely taken into the engine room 1 from the wind guide port 8, and the oil pan 9 of the transmission arranged rearward can be effectively cooled.

It is preferable that the inclination of the inclined portion 6 is as gentle as possible. However, it is selected to have an appropriate size so as not to interfere with devices such as the transmission oil pan 9 disposed in the engine room 1. Needless to say, a device other than the transmission oil pan may be appropriately cooled by the traveling wind taken into the engine room from the air guide port.

[0014]

In the vehicle undercover according to the present invention, the vertical wall portion extends upward from the substantially horizontal rear end, and the flat portion extends substantially horizontally rearward from the upper end of the vertical wall portion. A vortex is generated along the lower surface of the flat part by the traveling wind flowing backward from the vertical wall part, and the lift acting on the front part of the vehicle can be reduced by the negative pressure effect of the vortex, while it is inclined from the rear end of the flat part When the traveling wind flows along the lower surface of the inclined section, the wind pressure is restored when the traveling wind flows along the lower surface of the inclined section, so that the traveling wind is reliably introduced into the engine room from the air guide port formed in the inclined section. Therefore, the devices arranged in the engine room can be effectively cooled by the traveling wind.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part lower surface of the embodiment.

FIG. 3 is a vertical sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a vertical sectional view taken along the line IV-IV in FIG. 2;

5 is an enlarged vertical cross-sectional view taken along a line VV in FIG. 4;

FIG. 6 is a diagram for explaining the effect of traveling wind.

FIG. 7 is a graph illustrating the effect of traveling wind.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine room 2 Under cover 3 Front part 4 Vertical wall part 5 Flat part 6 Inclined part 7 Wind guideway 8 Wind guide port 9 Transmission oil pan 20 Eddy current

Continuation of front page (56) References JP-A-4-331670 (JP, A) JP-A-1-73471 (JP, U) JP-A-63-145715 (JP, U) JP-A-59-135282 (JP, U) , U) Japanese Utility Model Application Showa 59-38176 (JP, U) Japanese Utility Model Application Showa 58-115472 (JP, U) Japanese Utility Model Application Hei 4-95575 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B62D 25/20

Claims (4)

(57) [Claims] 1. A substantially horizontal front portion, a vertical wall portion extending upward from a rear end of the front portion, and substantially rearward from an upper end of the vertical wall portion. An undercover for a vehicle, comprising: a flat portion extending horizontally, an inclined portion extending rearward and downward from a rear end of the flat portion, and a ventilation opening formed in the inclined portion into the engine room. 2. The undercover for a vehicle according to claim 1, wherein a length of the flat portion is six times or more a vertical distance of the vertical wall portion in front of the air guide port. 3. The vehicle undercover according to claim 2, wherein the length of the flat portion is 6 to 7 times the vertical distance of the vertical wall portion. 4. The undercover for a vehicle according to claim 1, wherein the air guide port is directed to an oil pan of a transmission disposed in the engine room.