JPH0725369A - Rear body structure for vehicle - Google Patents

Abstract

PURPOSE:To effectively exhaust turbulence generated within a rear tire house while making a reduction in vehicle air resistance compatible with an improvement in vehicle stability against cross wind by areodynamically treating the rear body structure of a vehicle. CONSTITUTION:Air resistance is reduced by squeezing at least a part of the rear side face of a vehicle 1 so as to be formed into a squeezed surface 3, and stability against cross wind is improved by providing a cross wind receiving section 5 having an outside face 4 roughly parallel with the longitudinal direction of the vehicle at a place parted from the squeezed surface 3 outwardly in the vehicle width direction. Moreover, a rear tire house inside aire exhaust means composed of a first oneing section 8a opening within a rear tire house, a second opening section 9 opening to a space faced to the aforesaid cross wind receiving section of the squeezed surface 3, and of a passage section 11 communicating both the opening sections 8a and 9 with each other, is provided, so that turbulence within the rear tire house 7 can thereby be effectively exhausted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear vehicle body structure of a vehicle, and more particularly, to an aerodynamic treatment at a rear portion of the vehicle body.

[0002]

2. Description of the Related Art Air resistance in the front-rear direction of a vehicle (hereinafter simply referred to as "air resistance") that a vehicle receives when it goes straight has a great influence on the power performance and fuel consumption of the vehicle. It is important to reduce the.

The air resistance in a practical vehicle is a turbulent turbulent flow (hereinafter referred to as a turbulent flow) formed downstream of the boundary layer of the air flow formed on the vehicle body surface when the vehicle goes straight and separated from the vehicle body surface at the rear end of the vehicle body. It is known that the size of the wake is greatly affected (the larger the size of the wake, the more the air resistance of the vehicle increases). Therefore, in order to reduce the air resistance of the vehicle, it is important to have a vehicle body structure that can reduce the size of such a wake.

Conventionally, there is known a vehicle in which the rear side surface of the vehicle body is gradually narrowed in the vehicle width direction as it extends rearward of the vehicle body in order to reduce air resistance. It is known that when the rear side surface of the vehicle body is narrowed down, the size of the wake can be reduced and the air resistance of the vehicle can be effectively reduced as compared with the case where the narrowing is not performed.

[0005]

By the way, when a vehicle receives a lateral wind when going straight, a pressure difference is generated on both side surfaces of the vehicle body and a lateral force acts on the vehicle, and the aerodynamic center of this lateral force is the center of the vehicle. When the vehicle is located in front of the center of gravity, a yawing moment M _Y in the direction of rotating the front of the vehicle to the leeward side acts on the vehicle. The generation of such a yawing moment M _Y adversely affects the steering stability when the vehicle receives a crosswind (hereinafter, referred to as “crosswind stability”). Therefore, in the vehicle, it is the same as reducing the air resistance. In addition, it is required that the yaw moment M _Y generated when a cross wind is received is small and the cross body stability is high.

However, in the case of the vehicle in which the rear side surface of the vehicle body is narrowed down, the air resistance of the vehicle becomes smaller as the degree of narrowing is strengthened, whereas the aerodynamic center of lateral force is more forward than the center of gravity as the strength is narrowed down. There is a problem in that the yaw moment M _Y generated when a crosswind is received becomes large, and it is generally difficult to achieve both reduction of air resistance and improvement of crosswind stability in the vehicle. .

In order to improve the crosswind stability, the area of the portion of the vehicle body that receives the dynamic pressure of the airflow obliquely from the front when the vehicle receives a crosswind is increased in the rear portion of the vehicle body, and the rear portion of the vehicle body is rotated to the leeward side. It is considered effective to increase the moment component, and as such a method, as shown in, for example, Japanese Unexamined Patent Publication (Kokai) No. 4-8681, there has been a method of extending along the boundary between the side surface and the upper surface of the rear part of the vehicle body. It is known to erect fins extending vertically. However, if such fins are provided, there is a problem that the fins may obstruct the field of view obliquely behind the vehicle.

In view of the above circumstances, it is desired to realize a vehicle body structure for the rear part of a vehicle, which can favorably achieve both reduction of air resistance of the vehicle and improvement of crosswind stability.

On the other hand, a turbulent air flow (hereinafter referred to as "turbulent flow") is generated in the rear tire house when the vehicle is running. Has been released to the department. The released turbulence disturbs the air flow along the side surface of the vehicle and causes the boundary layer of the air flow to be separated from the vehicle body surface, so that the air resistance of the vehicle increases. As described above, the turbulent flow generated in the rear tire house also contributes to increasing the air resistance of the vehicle. If the turbulence generated in such a rear tire house can be discharged from the inside of the rear tire house without disturbing the flow of the air flow along the side surface of the vehicle, it is considered possible to further reduce the air resistance of the vehicle. To be In that case, it is desirable to discharge the turbulent flow generated in the rear tire house as efficiently as possible. Furthermore, by reducing the size of the wake generated behind the vehicle, it is possible to reduce the air resistance of the vehicle and to stabilize the crosswind of the vehicle at the same time, while efficiently reducing the turbulence generated in the rear tire house. It would be even more convenient if it could be discharged.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to favorably achieve both reduction of air resistance of a vehicle and stability of crosswind while efficiently producing turbulence in a rear tire house. It is an object of the present invention to provide a rear body structure of a vehicle that can be discharged well.

[0011]

According to a first aspect of the present invention, there is provided a rear vehicle body structure according to the present invention, wherein at least a part of a rear side surface of the vehicle is narrowed inward in the vehicle width direction as it extends rearward of the vehicle body. And a cross wind receiving portion provided outside the narrowing surface in the vehicle width direction and having an outer surface that is substantially parallel to the vehicle body front-rear direction, and further includes a first opening opening in the rear tire house. An opening portion, a second opening portion that opens in a portion of the narrowed surface that faces the lateral wind receiving portion, or a portion that is located rearward of the facing portion of the narrow wind surface, the second opening portion, and the second opening portion. 1 is provided with a rear tire house in-air discharging means including a passage portion connecting the first opening portion.

The above-mentioned "rear side surface of the vehicle" means a surface extending in the vehicle front-rear direction and the up-down direction in the rear portion of the vehicle, and also includes the side surface of the rear bumper and the like.

According to a second aspect of the present invention, there is provided a rear vehicle body structure according to the first aspect of the present invention.
The passage portion is formed by a bumper outer and a bumper inner which form a rear bumper.

[0014]

As described above, in the vehicle rear body structure according to the present invention, since at least a part of the rear side surface of the vehicle is the narrowing surface, the wake that occurs behind the vehicle when the vehicle goes straight ahead. Since the size of the vehicle can be reduced, the air resistance of the vehicle can be reduced.

Further, since the vehicle is provided with a lateral wind receiving portion having an outer side surface substantially parallel to the longitudinal direction of the vehicle body, when the vehicle receives a lateral wind while traveling, the dynamic pressure of the air flow obliquely from the front of the vehicle is cross winded. The outer side surface of the receiving portion is efficiently received, which effectively increases the rotational moment component that tends to direct the rear portion of the vehicle body to the leeward side. Therefore, the yawing moment M _Y
Can be reduced, and cross-wind stability can be improved.

Unlike the conventional fins described above,
Since the crosswind receiving portion is arranged at a position outside the narrowing surface forming the rear side surface of the vehicle in the vehicle width direction, the crosswind receiving portion does not hinder the rear view of the vehicle.

Further, the air flow along the narrowing surface when the vehicle is traveling is restricted by the crosswind receiving portion between the narrowing surface and the crosswind receiving portion toward the inner side in the vehicle width direction. The flow velocity becomes higher than that of the case where no portion is provided, and a large negative pressure is generated in the portion of the narrowing surface facing the lateral wind receiving portion and the portion positioned rearward of the vehicle body with respect to the facing portion. Therefore, the turbulent flow generated in the rear tire house is
The gas is efficiently guided to the outside of the vehicle from the first opening portion to the passage portion, and further from the second opening portion opened in the portion where the negative pressure is large. As described above, in the present invention, by providing the second opening in the portion having a large negative pressure, the turbulent flow in the rear tire house can be discharged more efficiently than in the case where the second opening is provided in the other portion. Therefore, it is possible to prevent the turbulent flow generated in the rear tire house from being released to the side surface of the vehicle, and to prevent separation of the boundary layer of the air flow along the side surface of the vehicle. It is possible to further reduce the resistance.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a vehicle body structure for a rear portion of a vehicle according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a vehicle rear part to which a vehicle rear body structure according to an embodiment of the present invention is applied, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is a rear bumper shown in FIG. It is a perspective view of a vehicle body right side portion.

In the vehicle 1 shown in FIG. 1, a side surface 2a of a portion of the rear bumper 2 extending in the vehicle front-rear direction is narrowed inward in the vehicle width direction as it extends rearward of the vehicle body to form a narrowing surface 3. As shown in FIG. 2, a lateral wind receiving member formed integrally with the rear bumper 2 has an outer side surface 4 that is substantially parallel to the front-rear direction of the vehicle body at a position spaced a predetermined distance outward from the narrowing surface 3 in the vehicle width direction. A section 5 is provided.

As shown in FIG. 1, the boundary layer of the air flow A formed on the side surface 2a of the rear bumper 2 when the vehicle 1 goes straight ahead is separated from the surface of the rear bumper 2 at the rear part of the vehicle body, and a wake B with a swirl downstream. To release. At this time, since the side surface 2a of the rear bumper 2 forms the narrowing surface 3, the size of the wake B generated is smaller than that in the case where the narrowing surface 3 is not provided. Therefore, the air resistance of the vehicle 1 is effectively reduced by providing the rear bumper 2 with the narrowing surface.

On the other hand, when the vehicle 1 receives a cross wind from the right side of the vehicle body when traveling straight ahead, the vehicle 1 travels while receiving an air flow from the diagonally right front. At this time, the outer side surface 4 of the side wind receiving portion 5 efficiently receives the dynamic pressure of the air flow from the front right diagonal direction, which causes a rotational moment that tends to direct the rear portion of the vehicle body to the leeward side. The yawing moment M _Y that tends to turn the front part of the vehicle body to the leeward side, which is expected to be excessive when the crosswind receiving part 5 is not provided.
Is canceled out and cross wind stability is improved.

As shown in FIG. 2, a rear tire house 7 for storing the rear tire 6 is formed at a front position of the rear bumper 2 on the vehicle body, and a front end of the rear bumper 2 is extended to a position facing the rear tire 6. There is. As shown in FIG. 3, a mud-preventing panel 8 is provided at the front end of the rear bumper 2.
Is attached, and a plurality of slits 8a are formed in the mud-preventing panel 8. For details, see IV-I in Figure 2.
As shown in FIG. 4, which is a cross-sectional view taken along line V, on the rear tire house 7 side of each slit 8a, mud and the like splashed up by the rear tire house 6 when the vehicle 1 is running enters the rear bumper 2 through the slit 8a. Defect 8b to prevent coming
Is provided. In this embodiment, each slit 8a constitutes the first opening of the present invention.

On the other hand, as shown in FIG. 2 and the like, a second opening is formed in a portion of the narrowing surface 3 formed on the side surface 2a of the rear bumper 2 slightly rearward of the vehicle body with respect to the portion facing the lateral wind receiving portion 5. An exhaust port 9 as a part is formed. The exhaust port 9 and each slit 8a are connected by a passage portion 11 formed by the rear bumper 2 and the quarter panel 10. As described above, in the present embodiment, the slits 8a, the exhaust port 9 and the passage portion 11 constitute the air discharging means in the rear tire house according to the present invention.

As shown in FIG. 2, when the vehicle 1 is running, a turbulent flow C is generated in the rear tire house 7. On the other hand, the air flow A along the narrowing surface 3 of the rear bumper 2 has a higher flow velocity between the narrowing surface 3 and the crosswind receiving portion 5, and a large negative impact is exerted on the narrowing surface 3 at the position where the exhaust port 9 is formed. Pressure is generated. Therefore, the turbulent flow C generated in the rear tire house 7 is guided through the slits 8a into the passage portion 11 and is efficiently discharged from the exhaust port 9 to the outside of the vehicle. Therefore, it is possible to effectively prevent a situation in which the turbulent flow C is discharged from the inside of the rear tire house 7 to the side surface of the vehicle 1, and the released turbulent flow disturbs the air flow A to cause separation of the boundary layer of the air flow A. Therefore, the air resistance of the vehicle 1 can be further reduced.

Next, another embodiment of the rear body structure of the vehicle according to the present invention will be described. FIG. 5 shows a main part of a rear body structure of a vehicle according to another embodiment of the present invention, II-I in FIG.
It is a figure equivalent to the I line sectional view. It should be noted that, of the constituent elements of the present embodiment shown in FIG. 5, the same constituent elements as those of the first embodiment are designated by the same reference numerals as those in the respective drawings, and detailed description thereof will be given. Is omitted.

The present embodiment is different from the above embodiment in that in the above embodiment, each slit 8a as the first opening and the second slit 8a
The passage portion 11 that connects the exhaust port 9 as the opening of the rear bumper 2 is formed by the rear bumper 2 and the quarter panel 10, while in the present embodiment, as shown in FIG.
The portion extending in the front-rear direction of the vehicle body is composed of a bumper outer 2A and a bumper inner 2B.
The point is that the passage portion 11 is formed by A and the bumper inner 2B. By doing so, it becomes possible to further enhance the function of the passage portion 11. The rest of the configuration is the same as that of the above-mentioned embodiment, so the explanation is omitted.

Although the embodiment of the vehicle rear body structure according to the present invention has been described above, the vehicle rear body structure according to the present invention is not limited to the specific mode of the embodiment, and various modifications may be made. Of course it is possible.

[Brief description of drawings]

FIG. 1 is a perspective view of a rear portion of a vehicle to which a rear body structure of a vehicle according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a perspective view of a right side portion of the rear bumper shown in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a view corresponding to a sectional view taken along line II-II in FIG. 1, showing a main part of a rear body structure of a vehicle according to another embodiment of the present invention.

[Explanation of symbols]

 1 Vehicle 2 Rear Bumper 2A Bumper Outer 2B Bumper Inner 3 Narrowing Surface 4 Outer Side of Crosswind Receiver 5 Crosswind Receiver 7 Rear Tire House 8a Slit (First Opening) 9 Exhaust (Second Opening) 11 Passage A Air Flow B Wake C Turbulence

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Kamimoto 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (2)

[Claims] 1. A narrowing surface in which at least a part of a rear side surface of the vehicle is narrowed inward in the vehicle width direction as it extends rearward of the vehicle body, and a front surface and a rear surface of the vehicle body which are provided apart from the narrowing surface outward in the vehicle width direction. A lateral wind receiving portion having an outer side surface substantially parallel to the direction, and a first opening opening into the rear tire house and a portion of the narrowing surface facing the lateral wind receiving portion or the facing side. A rear tire house in-air exhausting means including a second opening opening at a portion located on the rear side of the vehicle body with respect to the opening portion and a passage connecting the second opening and the first opening is provided. The rear body structure of the vehicle, which is characterized in that 2. The rear vehicle body structure according to claim 1, wherein the passage portion is formed by a bumper outer and a bumper inner forming a rear bumper.