JP2008247121A - Lower bodywork of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish compatibly an enhancement of the Cd value and protection of an under-cover by improving the lower bodywork having under-cover. <P>SOLUTION: A lower body work of a vehicle according to this invention is equipped with a bumper facia 5, a sub-frame having a cross-member 62 extending across the vehicle width directly behind a radiator 22, and a front under-cover 10a covering the area between the bottom of the bumper facia 5 and the undersurface of the cross-member 62. The front under-cover 10a has a bottom part 111 spreading approximately horizontally in a position under the cross-member 62 and a rising part 112 rising in bending to over the back in a position behind the bottom part 111 and continued to the rear edge. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle body lower structure.

  Conventionally, in order to improve an air drag coefficient (Cd value), a vehicle lower surface portion is covered with an under cover. An example of the structure of the undercover is disclosed in Patent Document 1, for example. Patent Document 1 relates to an automobile provided with a so-called perimeter frame formed of a rectangular frame as a subframe (suspension frame) that mounts a suspension member and is joined to the lower side of a body side frame. An undercover structure is disclosed in which a jack-up point provided in a portion is easily visible from the front of the vehicle.

JP 2004-306897 A

  From the viewpoint of improving the Cd value, the smaller the amount of airflow entering the lower surface of the vehicle, the better. Then, it is desirable that the position of the under cover is as low as possible.

  However, as a matter of course, when the position of the under cover is simply lowered, the under cover easily interferes with the road surface, and the possibility that the under cover is damaged increases.

  Accordingly, an object of the present invention is to improve the Cd value and protect the undercover by improving the vehicle body lower structure having the undercover.

  According to one aspect of the present invention, before covering a space between a bumper fascia, a subframe having a cross member extending in the vehicle width direction immediately after the radiator, and a lower end portion of the bumper fascia and a lower surface portion of the cross member A lower part of the vehicle body comprising a bottom under cover, wherein the front under cover has a bottom portion that extends substantially horizontally at a position below the cross member, and a rear edge that bends upward and rearwardly behind the bottom portion. The vehicle body lower part structure characterized by having a rising part which continues in a row.

  According to this configuration, the bottom portion of the front under cover can be disposed at a position lower than the cross member, so that the amount of airflow entering the lower surface of the vehicle body can be reduced, and the air drag coefficient (Cd value) can be improved. Can do. Moreover, even if the front under cover is struck against the road surface when the front wheel is stepped down due to the presence of the rising portion, the shock is absorbed by the bending of the rising portion, so the front under cover is damaged. Can be prevented.

  According to a preferred embodiment of the present invention, preferably, the front under cover has a front inclined portion that is inclined rearward and downward from the front edge portion and continues to the bottom portion. A load clearance can be secured by the forward inclined portion. Compared to the case where an undercover is used that simply connects the lower end of the bumper fascia and the cross member in a straight line, it is possible to prevent wind interference, so that the airflow under the lower surface of the vehicle body is not disturbed, and the Cd value is Can be improved. Furthermore, the approach angle and the low under guard can be compatible.

  According to a preferred embodiment of the present invention, the front edge portion is further fixed to the cross member, and further includes a rear under cover that extends downward from the engine. It is preferable that the front under cover and the rear under cover have a rising portion that is continuous with the edge portion, and form a vehicle body lower surface portion that is continuous at the front and rear at substantially the same height.

  According to this configuration, the rear under cover can be arranged at a position lower than the cross member continuously from the front under cover, and the air drag coefficient (Cd value) can be improved without disturbing the airflow under the lower surface of the vehicle body. it can. In addition, due to the presence of the rising portion of the rear under cover, even if the rear under cover is struck against the road surface when the front wheel is stepped down, the impact is absorbed by the bending of the rising portion, so the rear under cover Breakage can be prevented.

  In a preferred embodiment of the present invention, a rear edge portion of the front under cover and a front edge portion of the rear under cover are fastened and fixed to the lower surface portion of the cross member. As a result, the end of the front or rear under cover is prevented from being bent, and the number of assembling steps can be reduced and the cost can be reduced.

  As described above, according to the present invention, it is possible to provide a vehicle body lower structure that achieves both improvement of the Cd value and protection of the undercover.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, It shows only the specific example advantageous for implementation of this invention. In addition, not all combinations of features described in the following embodiments are essential as the problem solving means of the present invention.

  FIG. 1 is a front side view of a vehicle A provided with a lower body structure according to the present embodiment, and FIG. 2 is a bottom view (partially sectional view) of the front of the vehicle A. FIG. 3 is an exploded perspective view (details omitted) of the vehicle body lower structure in front of the vehicle A.

  The vehicle A includes left and right front wheels 1 and 1 that are steered wheels, and wheel houses 2 and 2 that house the front wheels 1 and 1 in a steerable manner. As shown in FIG. 1, a front fender panel 7 is joined to the upper part of the wheel house 2 on the outside of the vehicle, and a front bumper fascia 5 is joined to the front part of the wheel house 2 and the front part of the front fender panel 7. Has been.

  The front wheels 1, 1 include wheels 1 a, 1 a and tires 1 b, 1 b mounted on the wheels 1 a, 1 a, and are configured to be steered via knuckle arms 4, 4. Brake devices 3 and 3 are provided on the front wheels 1 and 1. The brake device 3 includes a brake disc 3a and a caliper 3b, and the brake disc 3a is fixed to the wheel 1a. The caliper 3b is supported by a not-shown stelling knuckle and is disposed across the brake disk 3a in a hook shape. The front wheel 1 is suspended independently on the left and right by a front suspension including a lower arm 8 (for example, double wishbone type, McPherson strut type).

  The vehicle A according to the present embodiment includes a perimeter frame 6 as a front subframe below a pair of left and right front side frames 21 and 21 (see FIG. 3) forming a skeleton of a monocoque body. The perimeter frame 6 is formed in a substantially rectangular shape by a pair of left and right frame members 61, 61 along the front side frames 21, 21, and first and second cross members 62, 62 extending in the vehicle width direction. At the time of a collision, it is structured to absorb high energy by both full wrap and offset. Lower arms 8 and 8 constituting the suspension are coupled to the perimeter frame 6 via rubber bushes 9 and 9. The perimeter frame 6 is coupled to the lower surfaces of the front side frames 21 and 21 via rubber mounts 64 provided at the four corners of the upper surface.

  As shown in FIG. 3, the radiator 22 is supported by a shroud 20 formed in a substantially rectangular shape with a synthetic resin such as polypropylene. The shroud 20 is disposed in front of an engine (not shown) installed in the upper part of the closed space formed by the perimeter frame 6, specifically, between the front end portions of the front side frames 21, 21, Provided immediately before the first cross member 62.

  At the front ends of the front side frames 21 and 21, flanges 21a and 21a are formed. A front bumper reinforcement 23 is positioned in front of the shroud 20 and the front side frames 21 and 21. The front reinforcement 23 basically functions as a reinforcing member for the bumper fascia 5 and is attached to the front ends of the front side frames 21 and 21. Crash cans 24 and 24 are attached to the rear of both ends of the front bumper reinforcement 23, respectively. The crash cans 24 and 24 function as energy absorbing members that absorb collision energy.

  The rear ends of the crash cans 24, 24 are further provided with flanges 25, 25 which are joined to the flanges 21a, 21a at the front ends of the front side frames 21, 21. The flanges 25, 25 have extension portions 25 a, 25 a that extend toward the center in the vehicle width direction and have shroud fastening holes formed at their tip portions. On the other hand, fastening portions 20a, 20a that are fastened with bolts through the shroud fastening holes are formed on the side portion of the front surface of the shroud 20. FIG. 4 shows a state in which the perimeter frame 6 is joined to the front side frames 21 and 21, the front bumper reinforcement 23 is attached, and the shroud 20 is supported by the flanges 25 and 25.

  An under cover is attached to the lower surface of the vehicle body in front of the vehicle A. As shown in FIGS. 2 and 3, the under cover in the present embodiment includes a front under cover 10 a that covers a space from the lower end portion of the front bumper facer 5 to the lower surface portion of the first cross member 62, and the front under cover. A side under cover 10b provided at the vehicle outer end of the cover 10a and a rear under cover 10c that covers a closed space formed by the perimeter frame 6, that is, extends under the engine. Such a divided configuration has the advantage that the individual undercovers can be made smaller and the mounting property can be improved.

  FIG. 5 is a perspective view of an external appearance of a main part when the bottom surface of the vehicle A is viewed from the lower left front side, and FIG. The characteristic structures of the front under cover 10a and the rear under cover 10c in the present embodiment are shown in FIGS.

  In the present embodiment, as shown in FIG. 6, the front edge portion of the front under cover 10 a is fastened and fixed to the lower end portion of the front bumper fascia 5 with, for example, bolts 101, and the rear edge portion is the first cross member 62. For example, the bolt 102 is fastened and fixed to the lower surface portion. As a result, the lower surface of the vehicle body between the front bumper facer 5 and the lower surface of the first cross member 62b is covered. Further, the front edge portion of the rear under cover 10c is also fixed to the lower surface portion of the first cross member 62, and the rear edge portion of the rear under cover 10c is fastened and fixed to the lower surface portion of the second cross member 63 with, for example, bolts 103. Is done.

  Conventionally, the shape of the front undercover is a straight line connecting the lower end portion of the front bumper fascia 5 and the lower surface portion of the first cross member 62 in a side view as shown by a broken line S in FIG. Was considered. On the other hand, in the present embodiment, the front under cover 10 a is set at a position below the broken line S, that is, at a position below the first cross member 62. Here, in the present embodiment, the front under cover 10a has a bottom portion 111 that spreads substantially horizontally, and in front of the bottom portion 111, the front under cover 10a faces downward from a front edge portion connected to the lower end portion of the front bumper fascia 5. And a front inclined portion 113 which is inclined to the bottom portion 111 and continues to the bottom portion 111.

  According to such a front under cover 10a, first, since it can be set at a lower position as compared with a conventional under-covered linear under cover (broken line S), the air current below the lower surface of the vehicle body is reduced. The amount of entry can be reduced, and the Cd value of the entire vehicle can be improved. In addition, a load clearance can be secured by the front inclined portion 113. It can be said that by providing such a forward inclined portion 113, both the approach angle and the low under guard can be achieved.

  In addition, the configuration of the front under cover 10a having the bottom portion 111 and the forward inclined portion 113 has the following effects.

  When the vehicle A travels, the traveling wind passing under the lower surface of the vehicle body flows into the wheel house 2 and flows out from the side surface of the vehicle body. The wheel house 2 that accommodates the front wheel 1 that is a steered wheel is formed with a large depth space in anticipation of the turning allowance of the front wheel 1, so that the amount of air that flows out from the wheel house 2 to the side surface of the vehicle body tends to increase. A large amount of air that flows out of the wheel house 2 becomes a trap of wind, which becomes a factor that disturbs the smooth air flow on the side surface of the vehicle body, and deteriorates the Cd value of the entire vehicle. Therefore, in order to improve the Cd value, it is necessary to reduce the traveling wind flowing into the wheel house 2.

  In this regard, in the case of adopting a conventionally considered straight front under cover (broken line S) in side view, air flowing under the front bumper and flowing along the front under cover to the rear of the vehicle body Because of the straight and continuous back-and-down inclined surface, the pressure gradually increases because the space between the front undercover and the road surface decreases toward the rear, and at this time, the wheel just outside the vehicle width direction It turns out that it flows into House 2 to escape.

  On the other hand, the front under cover 10a in the present embodiment has a bottom portion 111 that extends substantially horizontally from the wheel house 2 to the front position, and the front inclined portion 113 is between the front of the bottom portion 111 and below the front bumper. Be placed. In other words, the air that enters the lower surface of the vehicle body from below the front bumper increases in pressure quickly because the space between the front inclined portion 113 and the road surface decreases toward the rear, and escapes to the outside in the vehicle width direction before reaching the wheel house 2. In addition, since a high-pressure flow is formed uniformly in the vehicle width direction between the bottom 111 and the road surface, the wheel house 2 reaches the position of the wheel house 2, so that the wheel house Unlike the existing prior art, the amount of air flowing into the wheel house 2 is reduced. Thereby, the air which flows out to the vehicle body side part from the wheel house 2 can be reduced, and the Cd value of the whole vehicle can be improved. This is a remarkable effect due to the configuration in which the front under cover 10a has the bottom portion 111 and the front inclined portion 113.

  On the other hand, as described above, the lower the position of the under cover, the more easily the under cover interferes with the road surface. Therefore, it is important to avoid damage to the under cover due to the interference.

  On the other hand, the front under cover 10a of the present embodiment has a first rising portion 112 that is bent rearward and upward and continues to the rear edge portion behind the bottom portion 111, and is continuous with the first rising portion 112. Thus, a first flange portion 112a formed at the rear of the vehicle body is formed. The first flange portion 112 a is fastened and fixed to the lower surface portion of the first cross member 62 with a bolt 102. When the front under cover 10a is struck against the road surface when the front wheel 1 is stepped down, the first rising portion 112 is bent, and the shock is absorbed by the bending. Thereby, the front under cover 10a can be protected from damage.

  Further, in the present embodiment, the rear under cover 10c extending below the engine 60 also has a second rising portion 114 that bends upward and rises and continues to the front edge portion, similarly to the front under cover 10a. The second rising portion 114 has a second flange portion 114a formed in front of the vehicle body. The second flange portion 114 a is fastened together with the bolt 102 together with the first flange portion 112 a to the lower surface portion of the first cross member 62. The second rising portion 114 can provide the same effect as that of the first rising portion 112 of the front under cover 10a to the rear under cover 10c. That is, when the rear under cover 10c is struck against the road surface when the front wheel 1 is stepped down, the second rising portion 114 is bent, and the shock is absorbed by this bending. As a result, the rear under cover 10c can be protected from damage.

  Further, due to the presence of the rising portion 114, the front under cover 10a and the rear under cover 10c can form a vehicle body lower surface portion that is continuous at the front and rear at substantially the same height. In this case, the rear under cover can also be arranged at a position lower than the cross member continuously from the front under cover, and the Cd value of the entire vehicle can be improved without disturbing the airflow below the lower surface of the vehicle body.

  Further, as described above, the front edge portion of the rear under cover 10c is also fixed to the lower surface portion of the first cross member 62. At this time, the rear edge of the front under cover 10a is secured with a bolt 102 as shown in the figure. The front edge part of the front part and the rear under cover 10 c are fastened and fixed to the lower surface part of the first cross member 62. By doing so, it is possible to prevent the rear edge portion of the front under cover 10a or the front edge portion of the rear under cover 10c from being twisted, and both can be fixed only by the bolt 102, so that the number of assembly steps can be reduced. And low cost.

1 is a front side view of a vehicle including a vehicle body lower part structure according to an embodiment. It is a bottom view (partial sectional view) of the front of the vehicle according to the embodiment. 1 is an exploded perspective view (details omitted) of a vehicle body lower structure in front of a vehicle according to an embodiment. It is a figure which shows an example of the state which attached the perimeter frame, the front bumper reinforcement, and the shroud to the front side frame. It is the principal part external appearance perspective view which looked at the bottom face of the vehicle which concerns on embodiment from the diagonally forward left lower part. It is BB sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Wheel house 3 Brake device 4 Knuckle arm 5 Front bumper fascia 6 Perimeter frame 10a Front under cover 10b Side under cover 10c Rear under cover 20 Shroud 21 Front side frame 22 Radiator

Claims (4)

Bumper Faisha,
A subframe having a cross member extending in the vehicle width direction immediately after the radiator;
A front under cover that covers a space between a lower end of the bumper fascia and a lower surface of the cross member;
A vehicle body lower structure comprising:
The front undercover is
A bottom portion extending substantially horizontally at a position below the cross member;
A rising portion that is bent upward and rearward at the rear of the bottom and is continuous with the rear edge;
The vehicle body lower structure characterized by having.   2. The vehicle body lower structure according to claim 1, wherein the front under cover includes a front inclined portion that is inclined rearward and downward from a front edge portion and continues to the bottom portion. The front edge is fixed to the cross member, and further comprises a rear under cover extending below the engine,
The rear under cover has a rising portion that bends upward and rises and continues to the front edge portion,
The vehicle body lower part structure according to claim 1, wherein the front under cover and the rear under cover form a vehicle body lower surface portion that is substantially the same height and that is continuous in the front and rear direction.   The vehicle body lower part structure according to claim 3, wherein a rear edge portion of the front under cover and a front edge portion of the rear under cover are fastened and fixed to a lower surface portion of the cross member. .

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