JP2015112951A - Lower end structure of vehicle rear part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively develop air-flow separation at the rear end of a rear bumper and smoothly flow an air flow toward the rear of a vehicle while suppressing the occurence of a turbulent flow to reduce air resistance during travelling.SOLUTION: A rear bumper 3 is provide with a first plane part 31 arranged at a vehicle lower end and a second plane part 32 arranged continuously in the rear end of the first plane part 31 and having an angle b different from of an angle a of the first plane part 31. The first plane part 31 has a length of 80 mm or more from the vehicle rear end in vehicle longitudinal directions. The first plane part 31 is arranged longer than the second plane part 32 in the vehicle longitudinal directions. A shape of the lower end part of the rear bumper 3 in the vehicle longitudinal directions is formed under the setting condition that the first plane part 31 and the second plane part 32 have different angles to a road surface G: the angle a of the first plane part 31 to the road face G is in a range of 0°-10°, and the angle b of the second plane part 32 to the road face G is in a range of 45°-170° and is larger than the angle a of the first plane part 31, and that an angular variation between the first plane part 31 and the second plane part 32 is large in a range of 35°-170°.

Description

  The present invention relates to a lower end structure of a rear portion of a vehicle for reducing air resistance by suppressing generation of a turbulent flow at the rear of the vehicle during traveling.

  Various members such as a fuel tank, a muffler, a rear suspension, a spare tire house, etc. are provided on the lower surface of the rear part of the vehicle, and these members generate turbulence as air resistance when the vehicle is running, There is a possibility that the air flow to the rear of the vehicle is deteriorated. When the flow of air to the rear of the vehicle becomes worse, the negative pressure acting on the rear surface of the vehicle increases, increasing the air resistance of the entire vehicle and reducing the fuel consumption of the vehicle.

  Therefore, some conventional vehicles are provided with an inclined surface on the lower surface of the rear part of the vehicle so that the ground height gradually increases toward the rear end of the vehicle body. Is generated, and the air resistance at the rear end of the vehicle is promoted to reduce air resistance (see, for example, Patent Document 1).

JP 2001-10543 A

  However, in the conventional vehicle rear structure described above, the angle of the inclined surface provided on the lower surface of the vehicle rear portion is not set in consideration of the shape of the rear end portion of the rear bumper located at the lower end of the vehicle rear portion. When the rear end portion of the rear bumper is formed with a small angle change with respect to the inclined surface, the airflow on the lower surface of the rear portion of the vehicle becomes a flow along the inclined surface at the lower portion of the rear end of the vehicle, and is wound up above the vehicle. There was a fear. When the air flow is wound upward, a turbulent flow (vortex) is generated immediately after passing through the rear part of the vehicle, and it is difficult to reduce air resistance due to negative pressure.

  The present invention has been made in view of such a situation, and an object of the present invention is to positively cause separation of the airflow at the rear end portion of the rear bumper, and to suppress the generation of a turbulent flow so that the airflow is directed to the rear of the vehicle. An object of the present invention is to provide a lower end structure of a rear portion of a vehicle that can flow smoothly and reduce air resistance during traveling of the vehicle.

  In order to solve the above-described problems of the prior art, the present invention includes a rear bumper disposed at a rear portion of a vehicle, and the rear bumper includes a first planar portion disposed at a lower end of the vehicle, and the first planar portion. A second flat surface portion that is arranged continuously at the rear end and has an angle different from the angle of the first flat surface portion, and the first flat surface portion has a length of 80 mm or more from the vehicle rear end in the vehicle front-rear direction. In the lower end structure of the rear part of the vehicle in which the first plane part is longer than the second plane part and arranged in the vehicle front-rear direction, between the first plane part and the second plane part. The angle with respect to the road surface is a small angle in the range of 0 ° to 10 °, and the angle with respect to the road surface of the second plane portion is 45 ° to 170 °. From the angle with respect to the road surface of the first plane portion Under the setting condition that the angle is large and the angle change between the first plane part and the second plane part is large and is in the range of 35 ° to 170 °, the lower end of the rear bumper across the vehicle width direction is set. A shape is formed.

  Further, in the present invention, a ridge line is provided at a bent portion between the first plane part and the second plane part, and the ridge line is formed in a curved shape having a curvature of 10 mm or less or a chamfer shape having a chamfer of 10 mm or less. ing.

  Furthermore, in this invention, the angle of the ridgeline formed between the said 1st plane part and the said 2nd plane part is an acute angle.

  In the present invention, the rear end portion of the rear bumper has a circular arc shape symmetrical with respect to the vehicle center line in the vehicle width direction so that the center portion in the vehicle width direction is located at the most rear side of the vehicle. It has a part.

  In the present invention, the first flat surface portion of the rear bumper and the lower surface of the spare tire house provided at the rear portion of the vehicle are continuously arranged at substantially the same height.

As described above, the lower end structure of the rear portion of the vehicle according to the present invention includes a rear bumper disposed at the rear portion of the vehicle, and the rear bumper includes a first flat portion disposed at the lower end of the vehicle and the first flat portion. A second flat surface portion that is continuously arranged at the rear end and has an angle different from the angle of the first flat surface portion is provided, and the first flat surface portion has a length of 80 mm or more from the vehicle rear end in the vehicle front-rear direction. The first plane portion is longer than the second plane portion and is disposed in the vehicle front-rear direction, and is between the first plane portion and the second plane portion with respect to the road surface. The angle is different, the angle with respect to the road surface of the first plane portion is a small angle in the range of 0 ° to 10 °, and the angle with respect to the road surface of the second plane portion is in the range of 45 ° to 170 °. There is an angle greater than the angle of the first plane portion with respect to the road surface, In addition, the shape of the lower end portion of the rear bumper extending in the vehicle width direction is formed under a setting condition that the angle change between the first plane portion and the second plane portion is large and is in a range of 35 ° to 170 °. Therefore, the airflow during vehicle travel toward the rear of the vehicle easily peels off from the surfaces of the first plane part and the second plane part at the folded part formed at the boundary between the first plane part and the second plane part.
Therefore, according to the lower end structure of the rear portion of the vehicle of the present invention, the airflow on the lower surface of the rear portion of the vehicle does not wind up upward along the lower surface of the rear portion of the vehicle immediately after passing through the rear end of the vehicle. It is possible to prevent a turbulent flow (vortex) from occurring at the rear of the vehicle. By preventing the flow from being disturbed, an increase in negative pressure can be suppressed, and air resistance during vehicle travel can be reduced.

  Further, in the present invention, a ridge line is provided at a bent portion between the first plane part and the second plane part, and the ridge line is formed in a curved shape having a curvature of 10 mm or less or a chamfer shape having a chamfer of 10 mm or less. Therefore, the shape of the ridgeline can be made small and clear, and the airflow toward the rear of the vehicle can be more easily separated from the surface of the plane portion, and the generation of negative pressure can be efficiently performed. Can be suppressed.

  Furthermore, in the present invention, since the angle of the ridge line formed between the first plane portion and the second plane portion is an acute angle, the airflow can be reliably peeled off at the rear end portion of the vehicle.

  In the present invention, the rear end portion of the rear bumper has an arc shape symmetrical with respect to the vehicle center line in the vehicle width direction so that the center portion in the vehicle width direction is located at the most rear side of the vehicle. Since it has the part which has, it becomes possible to change partially the timing which an airflow peels, and can control an airflow. In other words, at the rear end of the rear bumper, the air flow can be made smoother by accelerating the separation at the left and right side portions in the vehicle width direction and slowing the separation at the center portion in the vehicle width direction. Thus, the generation of turbulence can be effectively suppressed.

  Furthermore, in the present invention, the first flat portion of the rear bumper and the lower surface of the spare tire house provided at the rear portion of the vehicle are continuously arranged at substantially the same height, so that they are long in the vehicle front-rear direction. A flat surface at the bottom of the vehicle can be secured, and the airflow separated at the rear end of the rear bumper is less likely to be disturbed, so that the generation of negative pressure can be reliably suppressed. The reason for this is that the occurrence of a turbulent flow can be effectively suppressed when the vehicle longitudinal direction length of the plane on the lower side of the vehicle is made as long as possible.

It is the top view which looked at the vehicle rear part to which the lower end structure concerning the embodiment of the present invention is applied from the lower part. It is sectional drawing which looked at the vehicle rear part to which the lower end structure of embodiment of this invention is applied from the vehicle side. It is sectional drawing which looked at the rear bumper of the vehicle rear part to which the lower end structure concerning other embodiment of this invention is applied from the vehicle side.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
1 and 2 show a lower end structure of a rear part of a vehicle according to an embodiment of the present invention. In the figure, the direction of arrow F indicates the front of the vehicle.

As shown in FIGS. 1 and 2, the vehicle rear portion 1 to which the lower end structure according to the embodiment of the present invention is applied is provided with a spare tire house 2 for storing a spare tire (not shown). A rear bumper 3 extending in the vehicle width direction is provided on the vehicle rear side of the spare tire house 2.
The spare tire house 2 is formed in a concave shape by drawing to project an intermediate portion of the rear floor panel to the lower side of the vehicle with the peripheral portion of the rear floor panel remaining, and a bottom surface portion 21 having a flat basic surface; And a vertical wall surface portion 22 surrounding the bottom surface portion 21. As shown in FIG. 1, a muffler disposed on the rear side of the fuel tank 11 for storing fuel and the exhaust pipe 12 is provided on the lower surface of the vehicle rear portion 1 located on the vehicle front side or both left and right sides of the spare tire house 2. 13, a rear suspension 14, a rear wheel 15, and the like are provided.

  As shown in FIG. 2, the lower end portion of the rear bumper 3 according to the present embodiment is arranged at the lower end of the vehicle, and is gently inclined along the vehicle front-rear direction. A second flat surface portion 32 that is arranged continuously at the rear end and is bent to be inclined obliquely upward toward the rear of the vehicle and has an angle b different from the angle a of the first flat surface portion 31 is provided. The first planar portion 31 has a longitudinal length L1 of 80 mm or more from the rear end of the vehicle in the longitudinal direction of the vehicle, and the longitudinal length L1 of the first planar portion 31 is the longitudinal length of the second planar portion 32. It is longer than L2 (L1> L2) and is arranged in the vehicle longitudinal direction.

In the lower end structure of the vehicle rear portion 1 of the present embodiment, the shape of the lower end portion of the rear bumper 3 in the vehicle width direction is formed under the following setting conditions. That is, the angle with respect to the road surface G is different between the first plane part 31 and the second plane part 32, and the angle a with respect to the road surface G of the first plane part 31 is a small angle in the range of 0 ° to 10 °. The angle b with respect to the road surface G of the second plane part 32 is in the range of 45 ° to 170 °, and is larger than the angle a with respect to the road surface G of the first plane part 31 (a <b). Therefore, the angle change between the first plane part 31 and the second plane part 32 is large and is in the range of 35 ° to 170 °. When the lower end portion of the rear bumper 3 extending in the vehicle width direction is formed in a shape in which the angle change between the first planar portion 31 and the second planar portion 32 is 35 ° or more, the first planar portion 31 and the second planar portion are formed. In the folding part c located at the boundary with the part 32, the airflow at the time of vehicle traveling toward the rear of the vehicle is easily separated from the surfaces of the first flat part 31 and the second flat part 32.
On the other hand, if the lower end portion of the rear bumper 3 in the vehicle width direction is formed in a shape in which the angle change between the first plane portion 31 and the second plane portion 32 is 35 ° or less, the first plane portion 31 and the second plane portion 31 In the folding part c located at the boundary between the two plane parts 32, the airflow toward the rear of the vehicle when the vehicle travels is difficult to peel off from the surfaces of the first plane part 31 and the second plane part 32, and the rear end of the vehicle is Immediately after passing, it is wound up along the lower surface of the lower end portion of the rear bumper 3, and a turbulent flow (vortex) occurs behind the vehicle.

  Further, as shown in FIG. 2, a ridge line 33 extending in the vehicle width direction is provided at the folding portion c located at the boundary between the first plane portion 31 and the second plane portion 32. The ridge line 33 is formed in a curved shape having a curvature of 10 mm (R10) or less or a chamfering shape having a chamfering of 10 mm (C10) or less. With such a curved shape or chamfered shape, the shape of the ridge line 33 becomes small and the presence of the ridge line 33 becomes clear. As a result, the airflow toward the rear of the vehicle when the vehicle is traveling is easily separated from the surfaces of the first flat surface portion 31 and the second flat surface portion 32, and the occurrence of the turbulent flow that is the cause of the negative pressure is suppressed. ing.

  Further, as shown in FIG. 1, the rear end portion of the rear bumper 3 of the present embodiment includes a central portion 34 disposed in a central region in the vehicle width direction, and left and right both sides disposed in left and right side regions in the vehicle width direction. And a central portion 34 in the vehicle width direction is formed so as to be located most rearward of the vehicle. Therefore, the central portion 34 in the vehicle width direction is a portion that draws a single arc shape that is symmetrical in the vehicle width direction with respect to the vehicle center line (CC line) so as to protrude toward the rear of the vehicle. It is configured. At the rear end portion of the rear bumper 3 having the central portion 34 having such a shape, the timing at which the airflow toward the rear of the vehicle during vehicle traveling is separated from the surfaces of the first flat portion 31 and the second flat portion 32 is partially set. By changing the speed at the left and right side portions 35 in the vehicle width direction faster and by lowering the separation at the center portion 34 in the vehicle width direction, the flow of the air flow becomes smooth and the generation of turbulent flow occurs. Can be suppressed.

  Furthermore, in the lower end structure of the vehicle rear portion 1 of the present embodiment, the first flat surface portion 31 of the rear bumper 3 and the lower surface of the bottom surface portion 21 of the spare tire house 2 are continuously arranged at substantially the same height. Yes. Therefore, the lower surface of the bottom surface portion 21 of the spare tire house 2 is formed so as to incline gently toward the vehicle rear toward the vehicle rear at the same angle as the first flat surface portion 31 of the rear bumper 3. Accordingly, the front and rear length of the plane at the bottom of the vehicle is a length obtained by combining the front and rear length of the bottom surface portion 21 of the spare tire house 2 and the front and rear length L1 of the first plane portion 31 of the rear bumper 3. Since a plane with a long longitudinal length in the vehicle front-rear direction that has the effect of suppressing the occurrence of turbulent flow is secured at the lower end of the vehicle, the air flow separated at the rear end of the rear bumper 3 is not disturbed and negative pressure is generated. Will be suppressed.

  Thus, in the lower end structure of the vehicle rear portion 1 according to the embodiment of the present invention, the rear bumper 3 disposed at the vehicle rear portion is disposed at the vehicle lower end and has a longitudinal length of 80 mm or more from the vehicle rear end in the vehicle longitudinal direction. A first flat surface portion 31 having L1 and a second flat surface portion 32 which is arranged continuously from the rear end of the first flat surface portion 31 and has an angle b different from the angle a of the first flat surface portion 31; The front-rear length L1 of the first plane portion 31 is longer than the front-rear length L2 of the second plane portion 32 and is disposed in the vehicle front-rear direction, and the road surface is between the first plane portion 31 and the second plane portion 32. The angle with respect to the road surface G of the first plane portion 31 is a small angle of 0 ° to 10 °, and the angle b of the second plane portion 32 with respect to the road surface G is 45 ° to 170 °, The angle b is larger than the angle a of the first plane part 31, and the first plane part Since the shape of the lower end portion of the rear bumper 3 in the vehicle width direction is formed under the setting condition that the angle change between the first flat surface portion 32 and the second flat surface portion 32 is 35 ° to 170 °, the first flat surface portion 31 and the second flat surface portion 32 At the folding part c between the two plane parts 32, an effect is obtained that the airflow during vehicle travel toward the rear of the vehicle is easily separated from the surfaces of the first plane part 31 and the second plane part 32. Accordingly, the airflow on the lower surface of the rear portion 1 of the vehicle did not wind up upward along the lower surface of the rear portion 1 of the vehicle immediately after passing through the rear bumper 3 at the rear end of the vehicle, and flowed smoothly to the rear of the vehicle. Generation of flow (vortex) can be suppressed. Since the turbulent flow does not occur, it is possible to suppress the generation of negative pressure, and it is possible to realize a reduction in air resistance during vehicle travel.

FIG. 3 shows a lower end structure of a vehicle rear portion according to another embodiment of the present invention. In the rear bumper 3 of this embodiment, unlike the ridge line 33 of the above embodiment, the ridge line 33a formed between the first plane part 31 and the second plane part 32a has an acute angle d smaller than a right angle. Have. Therefore, the second flat surface portion 32a is formed by folding the rear end side lower portion of the rear bumper 3 located at the rear end of the first flat surface portion 31 toward the first flat surface portion 31 in front of the vehicle, and toward the front of the vehicle. The first flat portion 31 is continuously arranged at the rear end while being inclined obliquely upward. In addition, the upper part of the second plane part 32a is formed in the same shape as the lower rear end face of the rear bumper 3 of the above-described embodiment through a bent part that is repeatedly bent. The other structure is the same as that of the said embodiment, and the same member is shown with the same code | symbol.
As described above, in the lower end structure of the vehicle rear portion 1 according to the present embodiment, the angle d of the ridge 33a formed between the first plane portion 31 and the second plane portion 32a is set to an acute angle. Occasionally, the air flow toward the rear of the vehicle can be reliably separated from the first plane portion 31 and the second plane portion 32a at the rear bumper 3 at the rear end of the vehicle, and the turbulent flow is generated by smoothly flowing the air flow toward the rear of the vehicle. Can be prevented.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle rear part 2 Spare tire house 3 Rear bumper 21 Bottom part 22 Vertical wall part
31 First plane part 32, 32a Second plane part 33, 33a Ridge line 34 Center part in the vehicle width direction 35 Side part in the vehicle width direction a Angle of the first plane part b Angle of the second plane part c Folded part d Edge of the ridge line Angle G Road surface L1 Front-rear length of the first plane part L2 Front-rear length of the second plane part

Claims (5)

A rear bumper disposed at a rear portion of the vehicle, the rear bumper being disposed continuously with a first flat portion disposed at a lower end of the vehicle and a rear end of the first flat portion; A second plane part having an angle different from the angle is provided, and the first plane part has a length of 80 mm or more from the rear end of the vehicle in the longitudinal direction of the vehicle, and the first plane part is the second plane part. In the lower end structure of the rear part of the vehicle that is arranged in the vehicle longitudinal direction longer than the plane part,
The angle with respect to the road surface is different between the first plane part and the second plane part, and the angle with respect to the road surface of the first plane part is a small angle in the range of 0 ° to 10 °,
An angle of the second plane portion with respect to the road surface is in a range of 45 ° to 170 °, and an angle greater than an angle of the first plane portion with respect to the road surface;
And in the setting condition that the angle change between the first plane part and the second plane part is large and is in the range of 35 ° to 170 °,
A lower end structure of a rear portion of the vehicle, wherein a shape of a lower end portion of the rear bumper in the vehicle width direction is formed.   The fold line between the first plane part and the second plane part is provided with a ridge line, and the ridge line has a curved shape with a curvature of 10 mm or less or a chamfer shape with a chamfer of 10 mm or less. The lower end structure of the vehicle rear part according to claim 1.   The lower end structure of the rear part of the vehicle according to claim 2, wherein an angle of a ridge line formed between the first plane part and the second plane part is an acute angle.   The rear end portion of the rear bumper has a portion that draws a single circular arc shape symmetrical in the vehicle width direction with respect to the vehicle center line so that the center portion in the vehicle width direction is located at the rearmost position of the vehicle. The lower end structure of the vehicle rear part according to any one of claims 1 to 3. The first flat portion of the rear bumper and a lower surface of a spare tire house provided at the rear portion of the vehicle are continuously arranged at substantially the same height. The lower end structure of the vehicle rear part as described in 2.

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