JPH09104368A - Air resistance reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish an air resistance reducing performance equal to or higher than that of a conventinal air resistance reducing device at a low cost, in a small size, and in a lightweight and simple structure. SOLUTION: An air resistance reducing device concerned is used in a car having a cab 2 protruding a head in a position apart toward the center from the edge 3d of the rear body front face 3b and therein reduces the air resistance which the rear body front face 3b receives. At this front face 3b, the first wind guide plate 5 is furnished which is extended forward in a position apart toward the center a certain distance from the mentioned edge 3d, and a bend 5c bent toward the center at a prescribed angle is formed at the front extremity of this wind guide plate 5, while the second wind guide plate 6 to lead air to the bend 5c is furnished in a position on the cab 2 nearer the edge 3d and ahead of the bend 5c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air resistance reducing device, and more particularly to an air resistance reducing device which is applied to a vehicle such as a truck and reduces the resistance of air received on the front surface of the cargo bed.

[0002]

2. Description of the Related Art The flow of air during traveling in an ordinary truck that does not have the above device will be described below with reference to FIG. The truck illustrated here is of a type that is provided with a box (van) type loading platform behind the cab and the loading platform projects to a position higher than the cab roof.

The air flow f ₁ hitting the front surface of the cab a and being repelled on the roof b generates a vortex r ₁ on the roof b. On the other hand, the flow f ₁ above the vortex r ₁ collides with the front surface part d of the loading platform c. And this collided flow f ₁ is
The flow velocity becomes zero due to being dammed at the collision portion e, and high pressure is generated in the vicinity of the collision portion e by converting velocity energy into pressure energy by the flow velocity. This high pressure is
A drag force is generated in a direction opposite to the traveling direction of, and this drag force is a major factor of air resistance.

The flow f ₁ stopped at the collision part e,
Furthermore, the flow f ₂ above it separates at the upper edge h of the front surface part d of the cargo bed to generate a separation vortex r ₂ on the cargo bed c. The slow flow in the separation region due to the separation vortex r ₂ is observed as a deficiency in the momentum of the fluid in the wake, and as a result, acts on the track g as a resistance. That is, according to the law of conservation of momentum, the change in momentum of the fluid per unit time is equal to the force that the fluid receives, and the track g reduces the momentum of the fluid, that is, the air flows f ₁ and f _{2 by} the amount of the air flow. A force is applied to f ₁ and f ₂ , and a resistance force is received as a reaction of the applied force.

A conventional device for reducing the air resistance received by such a truck bed is shown below.

FIG. 11 shows what is called an air deflector (hereinafter referred to as an air differential) i, which is a roof b.
It has an inclined surface j connecting the front edge and the upper edge h of the front surface of the luggage carrier, and has a substantially triangular box shape provided on the cab roof b. The air diff i has an outer shape that is substantially streamlined to rectify the flow and becomes a stagnation point of the flow.
Of high pressure and resistance due to momentum loss in the wake due to separation on the bed c are prevented.

Further, what is shown in FIG. 12 is called a fence k, in which the flat plates l ₁ and l ₂ are assembled horizontally and vertically in the shape of a cross girder and are mounted on the front surface portion d of the cargo bed. In this, as shown in FIG. 15, a part of the flow f ₃ coming from the front of the loading platform separates at the front edge of the horizontal flat plate l ₁ to generate a vortex r ₃ with the loading platform front face portion d. Let And this vortex r
₃ generates a negative pressure, that is, a pressure directed in the traveling direction of the truck g to prevent the high pressure at the collision portion e. On the other hand, the flow f ₃ passing over the vortex r ₃ becomes a flow along the upper surface part m of the loading platform, thereby reducing the occurrence of the above-mentioned separation and reducing the resistance. Such a rectifying effect is
The same occurs on the side of the loading platform c due to the vertically extending flat plate l ₂ . In addition, as the conventional reports related to this fence, there are SAE paper 931893, Japanese Utility Model Laid-Open No. 62-184092 and Japanese Patent Laid-Open No. 60-110575.

[0008]

However, the above-mentioned conventional device has the following drawbacks.

(1) Air differential: large, heavy, and expensive.

A rectifying effect cannot be expected on the side of the cargo bed.

As shown in FIG. 13, in a normal small or medium-sized truck, the roof b of the cab a is narrower than that on the floor side, and the width w _{1 of the} air diff i is equal to the width w ₂ of the roof. It is not allowed to exceed it due to legal regulations. Since the width w ₂ of the roof is considerably smaller than the width w ₃ of the loading platform, there is a relatively large space on the side of the air diff i, and this space creates a state without the air diff i to prevent collision of air flow and vortexes. Cause an outbreak.

When the height of the cargo bed is high, it is practically impossible to mount the air differential.

This is a problem that occurs when the height position of the upper surface of the loading platform is considerably higher than the height position of the cab roof.
If an air diff is to be formed so as to connect the front end of the cab roof to the upper end of the front surface of the luggage carrier, the air diff will have to be a huge vertically long size, which may increase the above-mentioned drawbacks.
On the other hand, as shown in FIG. 14A, if the size of the air differential i is set so that it does not reach the upper end h of the front surface h of the luggage carrier, the portion not covered by the air diff i on the front surface d of the luggage carrier i. You can't expect that effect. Further, as shown in FIG. 14B, even if the air diff i is huge, the inclined surface j is bent sharply in the vicinity of the upper end of the air diff i, and a separation region (separation vortex r ₂ ) is easily formed on the upper surface of the loading platform. A problem arises.

It is practically difficult to prepare a plurality of variations in which the dimensions are optimized according to the vehicle type. Note that there are some types in which the angle of the inclined surface can be adjusted according to the height of the platform, but the structure is complicated and expensive.

(2) Fence The fence is intended to alleviate the above-mentioned drawbacks of the air diff to some extent, that is, it is compact, lightweight and inexpensive because it is composed of only a flat plate, and a vertical flat plate exerts a rectifying effect on the side of the cargo bed. The advantage is that it can be installed regardless of the height of the loading platform, and it can be applied to a wide range of vehicle types simply by adjusting the length of the flat plate. Further, since the fence changes the local flow direction, it can exert a flow regulating effect regardless of the height of the bed.

However, there are the following drawbacks.

As shown in FIG. 15, a collision part s as a stagnation point is formed on the lower side of the horizontal flat plate l ₁ , and a high pressure is generated.

A peeling area t is slightly left on the upper surface m of the loading platform.

The flow f ₃ coming to the upper side of the horizontal flat plate l ₁ is
The mean horizontal tilt of the flow changes unsteadily, ie f ₄ and f ₅
Since the state is alternately set to the unsteady state, the flow cannot be given to the horizontal flat plate l ₁ at a constant angle, and the effect is reduced. (The above is also applicable to the vertical flat plate.) For these reasons, in the case of a fence, the air resistance reduction effect is 20 to 30% inferior to that of an optimally shaped air differential. It is confirmed from the results of the actual running test.

[0020]

SUMMARY OF THE INVENTION The present invention is a device for reducing the resistance of the air received on the front surface of a luggage carrier in a vehicle having a cab projecting forward from the edge of the front surface of the luggage carrier at a position separated from the edge on the center side. In the above, on the front surface of the cargo bed, a first air guide plate extending forward at a position separated from the edge by a predetermined distance to the center side is provided, and at the front end of the first air guide plate,
A refraction portion is formed that is refracted toward the center by a predetermined angle, and a second air guide plate that guides air to the refraction portion is provided at a position on the edge side of the cab and in front of the refraction portion. It is a thing.

When the above-mentioned device is applied to a truck, the first baffle plate is provided in the front part of the loading platform, especially near the upper end part thereof, and the second baffle plate is provided in the cab roof, the second baffle plate is provided. The airflow that hits the plate is guided to the bending portion of the first baffle plate, and is guided to the front of the upper edge of the front surface of the luggage carrier in accordance with the inclination thereof. Then, it is pushed downward by the upper air flow,
The flow is changed so as to follow the upper surface of the loading platform, so that the flow smoothly flows along the upper surface of the loading platform.

Further, the present invention is a vehicle having a cab projecting forward at a position separated from the edge of the front surface of the loading platform toward the center side, and a mounting body projecting forward is provided on the front surface of the loading platform. In the device for reducing the resistance of air received on the front surface of the carrier and the front surface of the body, a concave portion is formed at a corner portion of the front surface of the body on the edge side, and the concave portion is formed.
A front surface forming portion that extends toward the center side by a predetermined distance from the end surface on the edge side of the body, an extending portion that extends forward from an extending end of the front surface forming portion, and a front end of the extending portion. And a baffle plate for guiding air to the refraction part at a position on the edge side of the cab and in front of the refraction part. Is.

This configuration is particularly applied to a vehicle in which a bodywork is provided on the front surface of the cargo bed. The extending portion and the bending portion are the first
This is equivalent to the air guide plate of No. 1 and, like the above, effectively reduces the air resistance together with the air guide plate provided in the cab.
In particular, since the concave portion composed of the extending portion and the bending portion is formed integrally with the body, the first baffle plate is not necessary, and the mounting and the like can be omitted.

[0024]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a van type truck equipped with the air resistance reducing device according to the present invention (the same applies to a trailer tractor).

As shown, the truck 1 has a cab 2
Has a box (van) type loading platform 3 behind it, and the loading platform 3 has a rectangular parallelepiped shape that is long in the longitudinal direction of the truck, that is, the vehicle. Bed 3 has a predetermined width W _3, a width W ₃ being greater than the width W ₂ of the cab roof (roof) 2a. Upper surface portion 3a of the loading platform 3
The height position H ₃ of the cab 2 is set higher than the height position H ₂ of the roof 2a of the cab 2. As a result, the loading platform 3 is projected to a position higher than the cab roof 2a, and the cab 2 is attached to the upper edge 3 of the loading platform front surface portion 3b.
It comes to project to the front at a position separated from the lower side to the height center side from d.

The air resistance reducing device 4 according to the present invention is provided in the space above the roof 2a of the cab 2 and in front of the front surface 3b of the luggage carrier.
Is arranged. The air resistance reduction device 4 is mainly composed of a first baffle plate 5 extending forward from the front face part 3b of the luggage carrier and a second baffle plate 6 standing obliquely rearward from the cab roof 2a. It

The first air guide plate 5 is integrally formed by bending a rectangular flat plate made of metal, resin, plastic or the like. The first baffle plate 5 is attached near the upper end of the luggage carrier front portion 3b and extends along the width direction of the luggage carrier 3 over the entire length thereof, and its rear end portion is attached to the luggage carrier front surface portion 3b so as to overlap. The mounting portion 5a is formed. As shown in FIG. 2, the mounting portion 5a is bent forward at a substantially right angle, and as a result, a substantially horizontal portion 5b continuous with the mounting portion 5a is formed.
Are integrally formed. A portion in front of the substantially horizontal portion 5b is bent obliquely downward at a predetermined angle, whereby a bending portion 5c continuous with the substantially horizontal portion 5b is integrally formed. The mounting portion 5a, the substantially horizontal portion 5b, and the bending portion 5
The front-rear length or front-rear width of c is constant along the bed width direction.

The second baffle plate 6 is also integrally formed by a rectangular flat plate made of metal, resin, plastic, or the like, similarly to the above. The second baffle plate 6 is connected along the front end edge 2b of the cab roof 2a and extends over the entire width thereof, and its front-rear length or front-rear width is constant along the width direction of the cab roof 2a. is there.

Here, a method for determining the dimensions of the first baffle plate 5 and the second baffle plate 6 will be described. Here, please refer to the side view of the truck 1 shown in FIG.

Consider an imaginary line Ls that is in contact with the front edge 2b of the cab roof 2a and the upper edge 3d of the cargo bed front surface portion 3b (that is, in contact with each corner).

The front-rear length L ₁ of the substantially horizontal portion 5b of the first baffle plate 5 is determined by the following equation, where L is the distance between the front end edge 2b of the cab roof 2a and the luggage carrier front surface portion 3b.

0.15L ≦ L ₁ ≦ 0.25L (1) Assuming a horizontal imaginary line L _H having one end P ₁ on the imaginary line Ls and the other end P ₂ on the front face part 3b of the cargo bed, This L _H
So that the length of P is equal to the length of L ₁ according to equation (1), P
Determine the position of ₂ . The position of P _{2 is} the position of the rear end of the substantially horizontal portion 5b. At this time, the distance between P ₂ and the upper edge 3d of the front surface portion 3b of the luggage carrier is h.

Inclination angle α of the substantially horizontal portion 5 b with respect to L _H
Is determined from the relationship with L ₁ shown in FIG.

Next, the front-rear length L ₂ of the refraction portion 5c is given by the following equation.

L ₂ = 0.2L (2) The inclination angle β of the refracting portion 5 c with respect to the substantially horizontal portion 5 b is represented by the following equation.

40 ≦ β ≦ 50 (°) (3) Further, the front-rear length L ₃ of the second baffle plate 6 is determined by the following equation. Here, H is the cab roof 2a and the luggage carrier upper surface portion 3
It is the distance in the height direction from a.

S = √ (L ² + H ² ) 0.25S ≦ L ₃ ≦ 0.3S (4) The inclination angle δ of the second baffle plate 6 with respect to Ls is as follows.

5 ≦ δ ≦ 9 (°) (5) The above results are obtained by wind tunnel experiments and the like, and based on these, the respective dimensions of the first baffle plate 5 and the second baffle plate 6 By determining, it is possible to obtain a stable and constant effect that is not significantly affected by the fluctuation of each parameter.

Thus, in the first baffle plate 5, the substantially horizontal portion 5b extends forward at a position separated from the upper end edge 3d of the luggage carrier front surface portion 3b by the height h toward the center of the height, and the bending portion 5c is refracted toward the center of height by a predetermined angle β at the front end of the substantially horizontal portion 5b. And the second baffle plate 6
At the front edge 2b of the cab roof 2a, it stands up diagonally below and forward of the bending portion 5c.

Next, FIG. 4 is a view showing a method of mounting the first baffle plate 5 on the front surface portion 3b of the cargo bed. The mounting portion 5a of the first baffle plate 5 extends along the width direction of the cargo bed. Stud bolts 11 are attached at predetermined intervals. Also stud bolt 11
Corresponding to the position of the bolt insertion hole 7
Is provided. The stud bolt 11 has an outer packing 8
Is inserted into the bolt insertion hole 7 from the outside of the loading platform 3 via
The first baffle plate 5 is fixed by tightening the nut 10 from the inside of the cargo bed 3 via the inside packing 9.

FIG. 5 is a view showing a method of attaching the second air guide plate 6, wherein the second air guide plate 6 is attached to the cab roof 2a via the attaching member 12.
The mounting member 12 has, at its base end, a holding portion 12a extending in the vehicle longitudinal direction. The sandwiching portion 12a has a bifurcated cross section, and its inner surface has a side edge portion 2c of the cab roof 2a.
The shape is suitable for. The sandwiching portion 12a sandwiches the side edge portion 2c of the cab roof 2a, that is, the rain gutter from the outside, and is fixed from above and below by a plurality of bolts 13. An extending portion 12b that extends to the center of the width on the cab roof 2a and extends upward is connected to the holding portion 12a.
Further, a mounting portion 12c for substantially mounting the second baffle plate 6 is formed at the tip or the upper end of the extending portion 12b. The mounting portion 12c is inclined so as to incline the second baffle plate 6 at the aforementioned angle. Then, the bolt 14 is inserted from below into the hole 12d of the mounting portion 12c, and the bolt 14 is provided with the threaded hole 6 formed in the thick portion 6a on the back surface of the second baffle plate 6.
The second baffle plate 6 is fixed by being fastened to b. Note that the door 15 is shown by a virtual line.

Next, the flow of air by the device 4 will be described.

As shown in FIG. 6, the air flow F ₁ that has hit the front surface of the cab 2 and has been repelled is the second air guide plate 6 as it is.
Be guided by and flow along. Then, the air flow F ₁ separates from the upper edge 6c of the second air guide plate 6, moves rearward, and reaches the refraction portion 5c of the first air guide plate 5. At this time, since the air flow F ₁ obliquely collides with the refraction portion 5c, the collision does not cause the flow velocity to be zero and no high pressure is generated. Therefore, the increase in air resistance is also very small. In addition, a part of the air flow F ₁ is separated along with the separation from the upper edge 6c of the second air guide plate 6, and a vortex S ₁ is generated behind the second air guide plate 6.

The air flow F ₁ that has collided with the refracting portion 5c is repelled upward as it is along the refracting portion 5c. Then, a part thereof is separated at the connection point of the refraction portion 5c and the substantially horizontal portion 5b, and a vortex S ₂ is generated in the space on the substantially horizontal portion 5b and in front of the luggage carrier front surface portion 3b. The vortex S ₂ generates a negative pressure and reduces the air resistance as in the case of the fence. Further, the air flow F ₁ rebounded by the refracting portion 5c.
Is guided to the front than in conventional fence flat (f indicated by ₃₎ the angle setting of the refraction section 5c, it pushed down by the upper air flow F ₂ than the upper edge of the loading platform front portion 3b At a position near 3d, the flow direction is changed to the flow in the horizontal direction, that is, along the upper surface 3a of the loading platform. This prevents the separation of the air flow F _{1 from} occurring on the upper surface 3a of the carrier.

In this device 4, the second baffle plate 6 causes the air flow F to flow.
₁ is always at a stable angle and the bending portion 5c (or the substantially horizontal portion 5
Since it is guided to b), the flow direction is stable, and it is possible to prevent the flow that would have flowed to the lower side of the fence flat plate in the past and the unsteady flow that alternately turns to the upper side and the lower side of the horizontal flat plate. The vortex S ₁ behind the second baffle plate 6 can promote the guidance of the air flow F _{1 to} the refraction portion 5c.

Further, as shown in FIG. 7, since the first baffle plate 5 is extended over the entire width of the luggage carrier 3 on the side of the luggage carrier 3, the air flow F ₃ guided to the first air guide plate 5 is applied to the side portion of the luggage carrier. It was also confirmed by the experimental results that the flow was changed to the flow along the surface of 3c and the flow was smooth without separation. Therefore, this device 4
Is also effective in reducing air resistance on the side of the cargo bed 3.

FIG. 8 shows a graph comparing the performances of the conventional device and the present device 4, and the vertical axis shows the Cd reduction rate ΔCd for a normal track without the device. As can be seen, in the case of the fence, the ΔCd value is considerably lower than that of the air differential, whereas in the case of the present device 4, a higher ΔCd value than that of the air differential is obtained and good performance is obtained.

As described above, according to the device 4, it is possible to eliminate the above-mentioned drawbacks (1) to (3) which have occurred in the conventional fence, and also to eliminate the drawbacks of the air differential due to the simple construction similar to that of the fence. The device is small, lightweight and inexpensive, and is not restricted by the height of the loading platform, and can be applied to a wide variety of vehicle types by only adjusting the length. In other words, this device 4
Is one that eliminates the disadvantages of the fence without sacrificing its advantages, and at the same time obtains the same or better performance as the air differential.

Next, FIG. 9 shows a modification. In this, the first baffle plate 5 and the second baffle plate 6 give a streamlined and three-dimensional shape so as to match (fit) the appearance style of the truck 1. Has been. What should be noted here is that the first baffle plate 5 and the second baffle plate 6 are formed with the side wall portions 5d and 6d. As shown in FIG. 7, according to the experimental results of the above-mentioned device (without the side wall portion), the streamline pattern of the flow F ₃ becomes a flow along the side surface 3c of the cargo bed already on the side of the first baffle plate 5. Therefore, even in the case of the present device having the side wall portions 5d and 6d, the streamline does not change so much, so that it is expected that the air resistance reducing effect does not change so much. On the other hand, the side walls 5d and 6d can improve the appearance and the mounting strength, and this device is advantageous in this respect. The first baffle plate 5 by this device
The second baffle plate 6 and the second baffle plate 6 are hollow integrally molded products made of resin or plastic.

Further, there are the following examples of application of the present apparatus.

Generally, in a truck used as a refrigerating vehicle or a refrigerating vehicle, an evaporator (evaporator, refrigerator inside cooler) is provided in front of a loading platform (refrigerating / freezing container) forming a refrigerating / freezing compartment. There are many.

FIG. 16 shows such a truck g, and an evaporator (not shown) is provided in an evaporator cover (hereinafter referred to as “evaporator cover”) n provided on a front surface portion d of the truck.
Is housed. The evaporator cover n protects the evaporator and at the same time reduces air resistance and improves appearance. However, this also unavoidably hinders the air flow.

That is, the flow of air during traveling is as shown in the figure. The airflow f ₆ that hits the front surface of the cab a and is repelled hits the front surface of the evaporation cover n to form a stagnation point p. Since the pressure near the stagnation point p becomes high, this becomes a major factor of air resistance. Further, in the illustrated example, the upper end of the front surface of the evaporation cover n is angled, and the flow f ₆ flows at this corner.
Is separated, a separation area t is generated on the upper surface of the loading platform c, which becomes momentum loss in the wake and increases air resistance.

On the other hand, another air flow f ₇ passing over the cab roof b is prevented from coming out upward due to the presence of the evaporation cover n, enters the gap between the cab a and the cargo bed c, and goes downward, It will be jetted from the bottom end to the vehicle floor q.

However, the jet flow f ₈ greatly disturbs the flow under the vehicle floor q, resulting in another situation of deterioration of running stability. That is, while traveling, the airflow preferably passes under the vehicle floor q smoothly and at a high speed to reduce the pressure under the vehicle floor q, prevent lift from being generated, and increase the ground contact pressure of the tire.
₈ collides with the frame, suspension, tires, etc. of the underfloor q of the vehicle and greatly disturbs the flow of the underfloor q of the vehicle. When this happens, the airflow does not become high speed, causing an increase in pressure under the floor,
This acts as a lift, lowering the ground contact pressure of the tire and deteriorating the running stability (straight running stability). Since the jet flow f ₈ itself is jetted downward, lift force is also generated by this alone.

Further, as shown in FIG. 17, the evaporation cover n
In the case where the whole is made into a curved surface configuration and the front end has a rounded shape, the separation of the flow f ₆ is alleviated at that portion, and although the above-mentioned separation area is reduced and the resistance is reduced, it is still small. Since there is a peeling area and a stagnation point p, a considerable amount of resistance remains. Further, the flow f ₇ that enters the gap and jets out below the vehicle floor q still remains.

On the other hand, as a solution to these problems, FIG.
There is a method of mounting the air diff i as shown in FIG. However, it is practically difficult to completely cover the evaporation cover n with the air diff i.
When the upper surface portion of the above is located below the upper surface portion of the loading platform c, a vortex r ₄ due to separation is generated in the space surrounded by the air differential i, the evaporation cover n, and the loading platform front surface portion d, which causes resistance. In addition, the large size, heavy weight and high cost of the air differential i still remain.

As described above, even in the case where a body typified by an evaporator cover (evaporator) is provided on the front surface of the loading platform, there are certain demands for reduction of air resistance and prevention of deterioration of running stability. ing.

Therefore, the present invention can meet such a demand, and by using the device of the present invention, the air resistance can be surely reduced, and the jet flow under the floor of the vehicle can be prevented to improve the running stability. Can be improved.

As shown in FIG. 19, the evaporation cover 20 provided on the front surface portion 3b of the luggage carrier is formed in a substantially rectangular parallelepiped box shape over the entire width of the luggage carrier 3. The upper surface portion 20a of the evaporation cover 20 is positioned at the same height as the luggage carrier upper surface portion 3a and forms the same plane. The front surface portion 20b of the evaporation cover 20 is a surface perpendicular to the upper surface portion 20a.
0b and the upper surface portion 20a are continuous in an angular shape, and are not rounded. This corner forms the upper edge 20d of the evaporative cover front surface portion 20b. On the other hand, the lower surface portion 20e of the evaporation cover 20 extends obliquely downward from the front surface portion 20b and is continuous in an angular shape.

On the front surface portion 20b of the evaporation cover 20,
The first baffle plate 5 of the device 4 is attached. Further, the second baffle plate 6 of the present device 4 is attached to the front end edge 2b of the cab roof 2a. The first baffle plate 5 and the second baffle plate 6 are configured in the same manner as described above, and their respective dimensions and mounting positions are such that the upper end edge 3d of the cargo bed front surface portion 3b is the upper end edge 20d of the evaporation cover front surface portion 20b. Substitution is determined by the above method.

In this case, the flow of air is the same as the flow described above, as shown in the figure. That is, the airflow F ₃ that has hit the front surface of the cab 2 and is splashed up is the second air guide plate 6 as it is.
And obliquely collide with the bending portion 5c of the first baffle plate 5. Due to this oblique collision, the generation of high voltage is prevented and the resistance is greatly reduced. After that, the air flow F ₃ is slanted upward, and a part of the air flow F ₃ is separated at the connection point of the refraction portion 5c and the substantially horizontal portion 5b to generate a vortex S ₃ . This vortex S ₃ generates a negative pressure to reduce the air resistance. Further, most of the remaining air flow F ₃ becomes a horizontal flow in the vicinity of the upper edge 20d of the evaporation cover front surface portion 20b in the same manner as described above, and does not cause separation at the upper edge 20d, and the upper surface 20a of the evaporation cover and the upper surface of the cargo bed are separated. Part 3
It will flow smoothly along a. As a result, all the factors that have increased the air resistance are eliminated, and the air resistance can be greatly reduced.

On the other hand, a part of the air flow F ₃ along the second air guide plate 6 is separated from the upper edge 6c of the second air guide plate 6 and swirls S.
Give rise to ₄ . This vortex S ₄ causes cabroff 2a
The upward flow is drastically reduced, which reduces the flow under the vehicle floor and improves running stability. Or the second
The air guide plate 6 of the above functions as a warp plate that blocks the flow on the cab roof 2a, and further exhibits the function of generating an air curtain by the upward flow above the second air guide plate 6, so that the cab It can be said that the flow on the roof 2a is blocked and the jet flow under the vehicle floor is reduced.

FIG. 20 shows another evaporation cover 21 having rounded corners (R), in which the evaporation cover 2 is used.
In No. 1, the upper surface portion 21a and the lower surface portion 21e are continuous in a curved shape with respect to the front surface portion 21b. At this time as well, the flow is the same as that described above, and a great reduction in air resistance and improvement in running stability can be simultaneously achieved. That is, since the peeling area slightly left on the upper surface portion 21a of the evaporation cover disappears, the resistance due to the momentum deficiency which the peeling area causes in the wake decreases. Also, the front part 2 of the evaporation cover
Since the stagnation point generated in 1b disappears, the resistance due to the high pressure at the stagnation point decreases.

FIG. 21 shows an example in which a structure corresponding to the first baffle plate 5 is integrally added to the evaporation cover 22. Specifically, at the corners of the front end and the upper end of the evaporation cover 22, the recess 2 extending over the entire width of the cargo bed 3 is formed.
3 is formed, and the outer surface shape of the recess 23 is partially the same as the first baffle plate 5. More specifically,
The concave portion 23 has a substantially horizontal portion 23b (extension portion) corresponding to the substantially horizontal portion 5b of the first air guide plate 5, a refraction portion 23c corresponding to the refraction portion 5c of the first air guide plate 5, and an upper surface. The vertical surface portion 22b (front surface forming portion) is extended from the portion 22a to the rear end edge of the substantially horizontal portion 23b. Here, the vertical surface portion 22b is a portion corresponding to the front surface portion of the luggage carrier or the front surface portion of the evaporation cover according to the previous example. The front lower portion 22d is continuous obliquely downward and rearward from the bent portion 23c, whereby the evaporation cover 22 has a pointed front portion 22c. The second air guide plate 6 (air guide plate) is left as it is at the front end edge of the upper surface of the cab 2.

Also in this example, the flow of the air flow is the same as that shown in FIG. 19 or FIG. 20, as shown in the figure. Therefore, the air resistance is surely reduced, and at the same time, the traveling stability can be secured. Particularly in this example, since the first baffle plate 5 is integrally formed by using the evaporation cover 22 which is a body, the effect that the manufacturing cost and the labor of the mounting work can be greatly reduced by this. is there.

Other various modifications are conceivable, and the present invention is not limited to the above-mentioned embodiment. Further, such a device is applicable not only to a truck but also to other objects such as a superstructure of a ship, a building, or a railway vehicle, particularly an object having a protruding portion on the front surface that receives wind. And the device above 90
It can also be rotated and applied to the side of the object. The truck is not limited to the one provided with the above-mentioned box-shaped carrier, and a truck provided with a cylindrical or elliptic cylinder-shaped carrier such as a liquid storage tank (a tank truck or the like) can be considered.

[0069]

The present invention exhibits the following excellent effects.

(1) Compared with the conventional air resistance reducing device, it is simpler, smaller in size, lighter in weight and cheaper in performance and equivalent or better in performance.

(2) Even if there is a bodywork on the front surface of the loading platform, the air resistance can be reduced, and at the same time, the jet flow under the floor of the vehicle can be prevented and the running stability can be improved.

(3) The structure corresponding to the first baffle plate is integrally added to the body, and the manufacturing cost and the labor of the mounting work can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a truck equipped with an air resistance reduction device according to the present invention.

FIG. 2 is a side view of a truck for showing respective dimensions of a first baffle plate and a second baffle plate.

FIG. 3 is a graph showing the relationship between α and L ₁ .

FIG. 4 is an exploded vertical side view showing a method of mounting the first baffle plate.

5A and 5B show a method for attaching a second baffle plate, FIG. 5A is a front view and FIG. 5B is a side view.

FIG. 6 is a side view showing the flow of air by the first baffle plate and the second baffle plate.

FIG. 7 is a plan view showing the flow of air on the side of the loading platform.

FIG. 8 is a graph for comparing a conventional device and the present device.

FIG. 9 is a perspective view showing a modified example.

FIG. 10 is a side view showing the flow of air in a normal truck.

FIG. 11 is a perspective view showing a truck equipped with a conventional air resistance reducing device (air deflector).

FIG. 12 is a perspective view showing a truck equipped with a conventional air resistance reduction device (fence).

FIG. 13 is a plan view showing the flow of air by the air deflector.

FIG. 14 is a side view showing an example of mounting the air deflector when the height of the loading platform is high.

FIG. 15 is a side view showing the flow of air through the fence.

FIG. 16 is a side view showing the flow of air in a truck equipped with a bodywork.

FIG. 17 is a side view showing the flow of air in a truck provided with a body of another shape.

FIG. 18 is a side view showing an air flow in a truck provided with a bodywork and an air deflector.

FIG. 19 is a side view showing an application example of the present device to a truck provided with a bodywork.

FIG. 20 is a side view showing an application example of the present device to a truck provided with a body of another shape.

FIG. 21 is a side view showing an example in which a structure corresponding to a first baffle plate is integrally added to a body structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 truck 2 cab 3 loading platform 3b front face part (front face) 3d upper edge (edge) 4 air resistance reducing device 5 first baffle plate 5b substantially horizontal part 5c bending part 6 second baffle plate (baffle plate) 20, 21, 22 Evaporator cover (bodywork) 22b Vertical surface portion (front surface forming portion) 23 Recessed portion 23b Substantially horizontal portion (extended portion) 23c Refraction portion h Distance β angle

Claims (3)

[Claims] 1. In a vehicle having a cab projecting forward at a position separated from the edge of the front surface of the loading platform toward the center side, in a device for reducing the resistance of air received on the front surface of the loading platform, the front surface of the loading platform includes: A first air guide plate extending forward is provided at a position separated from the edge by a predetermined distance toward the center,
At the front end of the first baffle plate, a refraction portion that is refracted toward the center by a predetermined angle is formed, and at the position on the edge side of the cab and in front of the refraction portion, the refraction portion is formed. An air resistance reducing device comprising a second air guide plate for guiding air. 2. The air resistance reducing device according to claim 1, wherein the luggage carrier has a body mounted on the front surface thereof and protruding forward, and the first baffle plate is provided on the front surface of the body mounted. 3. A vehicle having a cab projecting forward at a position separated from the edge of the front surface of the loading platform toward the center side, and a body projecting forwardly on the front loading surface of the loading platform. And a device for reducing air resistance received on the front surface of the body, wherein a recess is formed in a corner portion of the front surface of the body on the edge side, and the recess is formed from the end surface on the edge side of the body. A front surface forming portion that extends toward the center side by a predetermined distance, an extension portion that extends forward from the extension end of the front surface forming portion, and a refraction that is formed at the front end of the extension portion and is bent toward the center side by a predetermined angle. And an air guide plate for guiding air to the refraction section at a position on the edge side of the cab and in front of the refraction section.