JP4591124B2 - Lift reduction device - Google Patents

Description

  The present invention relates to a lift reducing device for reducing lift acting on an automobile.

  Conventionally, a structure in which a main floor cover 12 is provided as shown in FIG. As a result, the floor becomes flat and the air resistance decreases, so that the air flow near the center of the lower part of the vehicle body flows straight to the rear of the vehicle body.

  However, in this structure, since there is an airflow entering the floor from the lower side of the vehicle body as indicated by the broken line C, the airflow that collides with the rear wheel 13 and the rear suspension 14 increases. As described above, when the airflow colliding with the underfloor parts increases, the underfloor pressure rises and the force to lift the vehicle body (lift) increases, and the grounding force of the vehicle body decreases and the steering stability performance deteriorates.

  For this reason, there is known a lift reducing device that is provided with a V-shaped protrusion 22 that opens rearward on the lower surface of the front under cover 11 and generates a downward force (down force) due to the negative pressure of the vertical vortex generated thereby. . An example of such a lift reduction device is disclosed in Patent Literature 1 and Patent Literature 2 below.

No. 1-15577 Japanese Patent Laid-Open No. 8-142928

  However, in the vehicle body lower structure disclosed in Patent Document 1 and Patent Document 2 described above, since the airflow flowing from the lower surface of the vehicle body to the floor cannot be eliminated, this airflow helps the pressure recovery of the airflow under the floor, When the pressure rises, lift is generated, and the ground contact force of the vehicle body is lowered, and the steering stability performance is lowered.

  Accordingly, it is an object of the present invention to provide a lift reduction device that suppresses airflow flowing under the floor from the lower side surface of the vehicle body and actively discharges the airflow under the floor to the lower side surface of the vehicle body.

A lift reducing apparatus according to a first aspect of the present invention (corresponding to claim 1) that solves the above-described problem is that air flowing into the lower surface of the vehicle body from the lower front surface of the vehicle body is discharged to the lower side surface of the vehicle body and flows into the lower surface of the vehicle body An air guide to suppress
The position of the air guide front end in the vehicle width direction is set to the inside of the front wheel and to the outside of the position of 25% of the vehicle width from the vehicle body side end,
The shape of the air guide is an eight-letter shape that opens from the front to the rear ,
A plurality of the air guides are provided, and the position of the front end portion of the air guide at the rear is set inside the position of the front end portion of the air guide at the front,
The air guide is disposed between a front wheel and a rear wheel;
The air guide is characterized Rukoto a plurality placed in the longitudinal direction.

The above second invention for solving the problems lift reducing device according to (corresponding to claim 2), in the lift reducing device according to a first inventions, the air guide is deformed by an external force, and when the external force is eliminated It is to be restored.

In third aspect the lift reducing device according to (corresponding to claim 3), lift reducing device according to any of the first invention or second invention for solving the above problems, the rubber the material of the air guide It is characterized by.

In lift reducing device according to any of the above fourth to solve the problem of the invention lift reducing device according to (corresponding to claim 4), the first invention to the third invention, after the air guide shape The end portion is substantially parallel to the vehicle width direction. That is, the shape of the air guide is substantially L-shaped (substantially inverted L-shaped).

Lift reduction device according to a fifth aspect of the present invention (corresponding to claim 5) to solve the above problem, the lift reducing device according to any of the first invention to the fourth invention, the front end shape of the air guide The curve direction is changed on the way from the part to the rear end part. That is, the shape of the air guide is substantially S-shaped (substantially inverted S-shaped).

In lift reducing device according to any of the above sixth invention for solving the problems lift reducing device according to (corresponding to claim 6), the first invention to the fifth invention, the air guide and the vehicle body lower surface of The cover is integrated.

According to the first invention, by providing an air guide on the lower surface of the vehicle body for discharging air flowing from the lower front surface of the vehicle body to the lower side surface of the vehicle body and suppressing air flowing from the lower side surface of the vehicle body, the rear wheel, the rear suspension, etc. The turbulent airflow that collides with the vehicle can be more actively discharged to the lower side surface of the vehicle body. Thereby, since the increase of the airflow which collides with underfloor parts can be prevented, the raise of the atmospheric pressure under the floor can be prevented and lift can be suppressed.
Further, the position of the front end of the air guide in the vehicle width direction is set to the inside of the front wheel and outside of the position of 25% of the vehicle width from the vehicle body side end, so that the rear wheel, the rear suspension, etc. are disturbed. The airflow can be discharged more actively to the lower side of the vehicle body. Thereby, since the increase of the airflow which collides with underfloor parts can be prevented, the raise of the atmospheric pressure under the floor can be prevented and lift can be suppressed.
Further, by making the shape of the air guide into an eight-letter shape that opens from the front to the rear, the turbulent airflow that collides with the rear wheels and the rear suspension can be positively discharged to the lower side surface of the vehicle body. Thereby, since the increase of the airflow which collides with underfloor parts can be prevented, the raise of the atmospheric pressure under the floor can be prevented and lift can be suppressed.
Also, by providing a plurality of air guides and setting the position of the front end of the air guide at the rear to the inside of the position of the front end of the air guide at the front, turbulent air currents that collide with the rear wheel, rear suspension, etc. It can be more actively discharged to the lower side of the vehicle body. Thereby, since the increase of the airflow which collides with underfloor parts can be prevented, the raise of the atmospheric pressure under the floor can be prevented and lift can be suppressed.

According to the second and third aspects of the invention, the air guide is deformed by an external force and is restored when the external force disappears, thereby preventing the air guide from being damaged when it comes into contact with the ground. The height of the guide can be increased to the limit.

According to the fourth invention, the shape of the air guide is an eight-letter shape that opens from the front to the rear, and the rear end is made substantially parallel to the vehicle width direction, so that it collides with the rear wheel, the rear suspension, and the like. Disturbed airflow can be discharged more actively to the lower side of the vehicle body, and lift can be reduced. Since this effect is proportional to the square of the vehicle speed, the higher the speed range, the more effective.

According to the fifth aspect of the present invention, the shape of the air guide is an eight-letter shape that opens from the front to the rear, and the curve direction is changed in the middle from the front end to the rear end. The turbulent airflow that collides with the vehicle can be positively discharged to the lower surface of the vehicle body. Further, the shape of the rear end portion of the air guide is a shape along the airflow so as not to disturb the air flow. For this reason, C _D (air resistance coefficient) of the air guide can be reduced.

  Further, the rear end portion of the air guide is a vertical wall extending in the front-rear direction. For this reason, like the conventional vehicle body lower structure, it can be prevented by the air flow and the vertical wall that discharge the air flow entering from the vehicle body lower side surface. Thereby, even when the vehicle is traveling at a low speed, it is possible to prevent an increase in the airflow that collides with the underfloor parts, so that it is possible to suppress lift even in the low speed region.

According to the sixth invention, by integrating the air guide and the cover on the lower surface of the vehicle body, the strength of the air guide is increased and the number of parts is reduced, thereby reducing the labor for installation and reducing the cost. be able to.

A lift reducing apparatus according to the present invention will be described with reference to FIGS. 1 is a perspective view of a vehicle equipped with a lift reducing device according to the present invention, FIG. 2 is a side view of the vehicle equipped with a lift reducing device according to the present invention, and FIG. 3 is a plan view of the lift reducing device according to the first embodiment. 4 is a plan view of the lift reducing device according to the second embodiment, FIG. 5 is a plan view of the lift reducing device according to the third embodiment, FIG. 6 is a sectional view taken along the line AA shown in FIG. 3, and FIG. is a graph showing the characteristics of the C _D in the air guide front end installation position. In the figure, Fr indicates the vehicle body front direction, In indicates the vehicle body inner side direction, and Up indicates the vehicle body upward direction.

  As shown in FIG. 1, a large front under cover 11 is installed between the left and right front wheels 10 below the engine room 20 (see FIG. 2) and the front bumper 21 (see FIG. 2) at the lower part of the vehicle body. A main floor cover 12 is installed on the lower surface of the vehicle body behind the large front under cover 11.

  In the case of a four-wheel drive vehicle and a rear wheel drive vehicle, a propeller shaft 18 (see FIG. 3) for transmitting power from the engine room 20 to the rear wheels is disposed. A rear differential 19 (see FIG. 3) is installed at the rear end of the propeller shaft 18. Rear wheels 13 are installed on the left and right of the rear differential 19. A rear suspension 14 is installed inside the rear wheel 13.

  An exhaust pipe 15 is installed so as to extend rearward from the engine room 20. A main muffler 16 is installed at the rear end of the exhaust pipe 15. An exhaust pipe 17 is installed on the main muffler 16.

  As shown in FIG. 3, the lift reducing apparatus according to this embodiment is provided on the lower surface of the vehicle body. When viewed from below, the air guides 1 and 2 have an approximately eight-letter shape that opens from the front to the rear. The air guides 1 and 2 are bilaterally symmetric, and two pairs are installed in the front and rear. Here, the front air guide 1 is a first air guide 1 and the rear air guide 2 is a second air guide 2. In this embodiment, two pairs of air guides 1 and 2 are installed as an example, but the number of installed air guides 1 and 2 may be increased or decreased as necessary.

The installation positions of the air guide front end portions 1a and 2a are set within the range indicated by α in the drawing, which is on the inner side of the front wheels and within approximately 25% of the vehicle width from the vehicle body side end. As shown in FIG. 7, when the installation position of the air guide front end portions 1a, 2a exceeds approximately 25% of the vehicle width from the outside in the vehicle width direction, C _D (air resistance coefficient) suddenly increases. It is because it ends.

When the installation position of the air guide front end portions 1a, 2a is around 25% of the vehicle width from the outside in the vehicle width direction, _CD is about 0.01. Further, when the air guide front end portions 1a and 2a are installed outside the front wheels, that is, behind the front wheels, the effect of exhausting the airflow to the lower surface of the vehicle body cannot be sufficiently obtained.

  The installation positions of the air guide rear end portions 1b and 2b are the end portions on the vehicle body side so as not to protrude from the vehicle body. The installation position of the second air guide front end 2a in the vehicle width direction is set to the inside of the installation position of the first air guide front end 1a.

  The air guides 1 and 2 are coupled to the lower surface of the main floor cover 12 by bolts or clips. In this embodiment, it is installed on the lower surface of the main floor cover 12 as an example. However, in the case of a vehicle body to which the main floor cover 12 is not attached, it may be directly coupled to the lower surface of the vehicle body with bolts or clips.

  The height h (FIG. 6) of the air guides 1 and 2 is preferably as high as possible. However, if the height is too high, the air guides 1 and 2 may come into contact with the ground. Since the ground height of the lower surface of the vehicle body varies depending on the type of the vehicle body, the optimum height h of the air guides 1 and 2 varies depending on the ground height of the lower surface of the vehicle body. As an example, the height h of the air guides 1 and 2 is about 50 mm. is there.

  Considering the case where the air guides 1 and 2 are in contact with the ground and curbstones, the air guides 1 and 2 are deformed by external force when they are in contact with the ground and curbstones, and are restored when the external force is lost. To. In order to realize such a function, the air guides 1 and 2 are manufactured using a resin material such as rubber.

  According to the lift reducing apparatus according to the present embodiment, as shown by the broken line D (FIG. 3), the turbulent airflow that collides with the rear wheel 13 and the rear suspension 14 can be positively discharged to the lower side surface of the vehicle body. . For this reason, it is possible to prevent the air flow indicated by the broken line C (FIG. 8) entering from the side surface of the lower part of the vehicle body as in the conventional lower body structure.

  Thereby, since the increase of the airflow which collides with underfloor parts can be prevented, the raise of the atmospheric pressure under the floor can be prevented and lift can be suppressed. In addition, the air current in the vicinity of the center of the vehicle body indicated by the broken line B is not discharged to the lower side surface of the vehicle body.

  In this embodiment, the lift reducing device of the first embodiment is shaped so that the turbulent airflow that collides with the rear wheel 13 and the rear suspension 14 can be more actively discharged to the lower side surface of the vehicle body.

  As shown in FIG. 4, the lift reducing apparatus according to this embodiment is provided on the lower surface of the vehicle body. When viewed from below, the shape of the air guides 3 and 4 is an eight shape that opens from the front to the rear, and the air guide rear end portions 3b and 4b are substantially parallel to the vehicle width direction. That is, the shape is substantially L-shaped (substantially inverted L-shaped).

  The air guides 3 and 4 are symmetrical, and two pairs of the air guides are installed in the front and rear. Here, the front air guide 3 is a first air guide 3 and the rear air guide 4 is a second air guide 4. In this embodiment, two pairs of air guides 3 and 4 are installed as an example, but the number of installed air guides 3 and 4 may be increased or decreased as necessary.

  The installation positions of the air guide front end portions 3a and 4a are within the range indicated by α in the drawing, which is inside the front wheel and within approximately 25% of the vehicle width from the vehicle body side end. The installation positions of the air guide rear end portions 3b and 4b are the vehicle body side end portions. The installation position of the second air guide front end 4a in the vehicle width direction is set to the inner side of the installation position of the first air guide front end 3a.

  According to the lift reducing apparatus according to the present embodiment, as shown by a broken line E in FIG. 4, the turbulent airflow colliding with the rear wheel 13 and the rear suspension 14 can be more actively discharged to the lower side surface of the vehicle body. it can. The lift reduction effect obtained by further preventing the air flow indicated by the broken line C (FIG. 8) entering from the lower side surface of the vehicle body as in the conventional lower body structure becomes more significant as the speed increases.

  Thus, the increase of the airflow which collides with underfloor parts can be prevented, and lift can be suppressed, so that it becomes a high speed area. In addition, the air current in the vicinity of the center of the vehicle body indicated by the broken line B is not discharged to the lower side surface of the vehicle body.

The shape of the lift reduction device of Example 1 in the present embodiment, discharged to actively underbody side a turbulent air flow that impinges on the rear wheel 13 and the rear suspension 14 or the like, and the C _D of the air guide 5 and 6 The shape is lower.

  As shown in FIG. 5, the lift reducing apparatus according to the present embodiment is provided on the lower surface of the vehicle body. When viewed from below, the air guides 5 and 6 have an eight-letter shape that opens from the front to the rear, and change the bending direction in the middle from the front ends 5a and 6a to the rear ends 5b and 6b. is there. That is, it is substantially S-shaped (substantially inverted S-shaped) as a whole.

  The air guides 5 and 6 are symmetrical, and two pairs of the air guides are installed in the front and rear. Here, the front air guide 5 is the first air guide 5, and the rear air guide 6 is the second air guide 6. In this embodiment, two pairs of air guides 5 and 6 are installed as an example, but the number of air guides 5 and 6 may be increased or decreased as necessary.

  The installation positions of the air guide front end portions 5a and 6a are within the range indicated by α in the drawing, which is on the inner side of the front wheels and within approximately 25% of the vehicle width from the vehicle body side end. The installation positions of the air guide rear end portions 5b and 6b are the vehicle body side end portions. The installation position of the second air guide front end 6a in the vehicle width direction is set to the inner side of the installation position of the first air guide front end 5a.

According to the lift reducing apparatus according to the present embodiment, as shown by the broken line F in FIG. 5, the turbulent airflow that collides with the rear wheel 13 and the rear suspension 14 can be positively discharged to the lower side surface of the vehicle body. . In addition, the shape of the air guide rear end portions 5b and 6b is a shape along the air flow so as not to disturb the air flow. Therefore, it is possible to reduce the C _D of the air guide 5 and 6.

  Further, the air guide rear end portions 5b and 6b are vertical walls extending in the front-rear direction. For this reason, the airflow shown with the broken line C (FIG. 8) which penetrate | invades from the vehicle body lower side surface like the conventional vehicle body lower part structure can be prevented by the discharged airflow and the vertical wall.

Thus, while preventing an increase in the air flow impinging on the floor parts, it is possible to suppress the disturbance of the flow of the vehicle side, it is possible to reduce the lift while suppressing small increase of C _D. In addition, the air current in the vicinity of the center of the vehicle body indicated by the broken line B is not discharged to the lower side surface of the vehicle body.

  The present invention is effective for reducing lift, which is a problem during high-speed driving, and improving mobility during sports driving and safety during normal high-speed driving.

1 is a perspective view of a vehicle equipped with a lift reducing device according to the present invention. 1 is a side view of a vehicle equipped with a lift reducing device according to the present invention. 1 is a plan view of a lift reducing apparatus according to Embodiment 1. FIG. 6 is a plan view of a lift reducing apparatus according to Embodiment 2. FIG. 10 is a plan view of a lift reducing device according to Embodiment 3. FIG. It is sectional drawing in the AA cross section shown in FIG. Is a graph showing the characteristics of the C _D in the air guide front end installation position. It is a top view of the conventional vehicle lower part structure.

Explanation of symbols

1, 2 Approximately eight-shaped air guides 1a, 2a Approximately eight-shaped air guide front ends 1b, 2b Approximately eight-shaped air guide rear ends 3, 4 Approximate L-shaped (substantially inverted L-shaped) air guides 3a, 4a Approx L Character-shaped (substantially inverted L-shaped) air guide front end portions 3b, 4b substantially L-shaped (substantially inverted L-shaped) air guide rear end portions 5, 6 substantially S-shaped (substantially inverted S-shaped) air guide 5a, 6a substantially S-shaped (substantially inverted S-shaped) air guide front end 5b, 6b substantially S-shaped (substantially inverted S-shaped) air guide rear end 10 front wheel 11 large front under cover 12 main floor cover 13 rear wheel 14 Rear suspension 15 Exhaust pipe 16 Main muffler 17 Exhaust pipe 18 Propeller shaft 19 Rear differential 20 Engine room 21 Front bumper 22 V-shaped projection

Claims (6)

Provided on the lower surface of the vehicle body is an air guide that discharges air flowing from the lower front surface of the vehicle body to the lower side surface of the vehicle body and suppresses air flowing from the lower surface of the vehicle body,
The position of the air guide front end in the vehicle width direction is set to the inside of the front wheel and to the outside of the position of 25% of the vehicle width from the vehicle body side end,
The shape of the air guide is an eight-letter shape that opens from the front to the rear ,
A plurality of the air guides are provided, and the position of the front end portion of the air guide at the rear is set inside the position of the front end portion of the air guide at the front,
The air guide is disposed between a front wheel and a rear wheel;
The air guide is lift-reducing device according to claim Rukoto a plurality placed in the longitudinal direction. The lift reducing apparatus according to claim 1 ,
A lift reducing device, wherein the air guide is deformed by an external force and is restored when the external force disappears. In the lift reducing apparatus according to claim 1 or 2 ,
A lift reducing device, wherein the air guide is made of rubber. In the lift reducing apparatus according to any one of claims 1 to 3 ,
A lift reducing device characterized in that the shape of the air guide is such that the rear end portion is substantially parallel to the vehicle width direction. In the lift reducing apparatus according to any one of claims 1 to 4 ,
A lift reducing device, wherein the shape of the air guide is changed in the curve direction in the middle from the front end portion to the rear end portion. In the lift reducing apparatus according to any one of claims 1 to 5 ,
A lift reducing apparatus, wherein the air guide and a cover on a lower surface of the vehicle body are integrated.

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