JP3304698B2 - Air resistance reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing air resistance, and more particularly to an apparatus applied to a truck for reducing the resistance of air received on the front of a carrier or bodywork .

[0002]

2. Description of the Related Art The flow of air during traveling in a normal truck without the above-mentioned device will be described below with reference to FIG. The truck exemplified here is of a type having a box (van) type carrier behind the cab, and the carrier protrudes to a position higher than the cab roof.

[0003] Cab a air flow f ₁ that is splashed onto the roof b hits the front generates a vortex r ₁ at its roof b. On the other hand, the flow f ₁ above the vortex r ₁ collides with the front part d of the bed c. And this collision flow f ₁ is
The flow velocity is reduced to zero by the damping at the collision portion e, and a high pressure is generated near the collision portion e by converting velocity energy into pressure energy by the flow velocity. This high pressure
Generates a drag in the direction opposite to the traveling direction of the vehicle, and this drag is a major factor in air resistance.

[0004] The flow f ₁ blocked at the collision portion e,
Furthermore and above the flow f _2, causing separation vortex r ₂ on loading platform c is peeled at the upper edge h of the loading platform front part d. The slow flow in the separation area based on the separation vortex r ₂ is observed as a lack of momentum of the fluid in the wake, and as a result acts as a resistance to the track g. That is, the law of conservation of momentum from the momentum change per unit of fluid time is equal to the force that the fluid is subjected, truck g is correspondingly obtained by reducing small momentum of fluid or air flow f _1, f _2, the air flow A force is applied to f ₁ and f ₂ , and a resistance is received as a reaction of the applied force.

[0005] A conventional apparatus for reducing the air resistance applied to the bed of such a truck will be described below.

FIG. 13 shows what is called an air deflector (hereinafter, referred to as an air differential) i, which is a roof b.
It is a substantially triangular box-shaped member provided on the cab roof b and having an inclined surface j connecting the front edge and the upper edge h of the front surface of the carrier. The air differential i has a substantially streamlined outer shape, straightens the flow, and forms the stagnation point of the flow.
, And the generation of resistance due to momentum loss in the wake due to separation on the carrier c.

FIG. 14 shows a fence k, which is formed by assembling flat plates l ₁ and l ₂ horizontally and vertically in a cross-girder manner and mounting the same on the front face d of the cargo bed. In this, as shown in FIG. 19, a portion of the flow f ₃ coming opposite the loading platform front, resulting a vortex r ₃ between the loading platform front part d was peeled at the front edge of the horizontal flat plate l ₁ Let it. And this vortex r
Numeral ₃ generates a negative pressure, that is, a pressure in the traveling direction of the track g to prevent the generation of a high pressure at the collision portion e. On the other hand, the flow f ₃ passing over the vortex r ₃ is a flow along the upper surface m of the loading platform, thereby preventing the occurrence of the separation and reducing the resistance. Such rectification effect also occurs in the same manner by a vertical flat plate l ₂ which extends vertically in the bed c side. Conventional reports related to the fence include SAE paper 931893, Japanese Utility Model Application Laid-Open No. Sho 62-184092, and Japanese Patent Application Laid-Open No. Sho 60-110575.

[0008] Then, a different track from the above-mentioned track,
That is, the following device is provided in a truck (tractor) of a type for towing a trailer.

FIG. 15 shows a nose cone n which has a substantially semi-cylindrical cross-section or a box-like shape attached to the front portion d of a trailer as a carrier c. FIG. 16 shows an air vane o, which is a blade-like member provided inwardly curved along the upper end edge and both side edges of the front surface portion d of the carrier. In each case, the flow is rectified in the same manner as described above, and the generation of high pressure at the front surface of the carrier and the generation of vortices at the upper surface of the carrier are prevented. In the air vane o, the blades on both side edges also prevent vortices from being generated on the side surfaces of the loading platform.

[0010]

However, the above-described conventional apparatus has the following disadvantages.

(1) Air differential Large, heavy, and expensive.

A rectifying effect on the side of the loading platform cannot be expected.

As shown in FIG. 17, in a normal small / medium-sized truck, the roof b of the cab a is narrower than the floor side, and the width w _{1 of the} air differential i is smaller than the width w ₂ of the roof. Exceeding the law is not allowed by law. Since the width w ₂ of the roof is much smaller than the width w ₃ of the bed, there is a relatively large space on the side of Eadefu i, this space collision or vortex of air flow to create a state where there is no Eadefu i Cause an outbreak.

If the height of the bed is high, it is virtually impossible to mount the air differential.

[0015] 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 the air differential is formed so as to connect the front end of the cab roof and the upper end of the front surface of the loading platform, the air differential must be made to be a vertically long and huge one, which may increase the above-mentioned drawbacks.
On the other hand, if the size of the air differential is set to a size that does not reach the upper end of the front surface of the loading platform, a portion not covered by the air differential is formed on the front surface of the loading platform, and the effect cannot be expected much. Also, even if the air differential is huge, there is a problem that the inclined surface is sharply bent in the vicinity of the upper end portion and a peeling area is easily formed on the upper surface of the loading platform.

It cannot be mounted on a specially equipped vehicle.

In a specially equipped vehicle p as shown in FIG. 18, a body q is arranged on a cab roof b, and there is no space for mounting an air differential.

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

(2) Fence The fence reduces the above-mentioned drawbacks of the air differential to a certain extent, that is, it is small, light and inexpensive because it is composed only of a flat plate. It has the advantage that it can be mounted on a specially equipped vehicle regardless of the height of the bed (attached to the front of the body), and can be adapted to any vehicle type by simply adjusting the length of the flat plate. And since a fence changes the direction of a local flow, the rectification effect which does not depend on the height of a carrier can be exhibited.

However, there are the following disadvantages.

As shown in FIG. 19, it will be able to collision portion s of the stagnation point on the lower horizontal plate-l _1, high pressure is generated.

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

[0023] replaced by the upper side coming flow f ₄ and comes to the lower flow f ₅ and are alternately and unsteady horizontal flat l _1, because not given the flow at an angle to the horizontal flat l _1, the effect is also reduced . (These are also true of vertical flat plates.) For these reasons, in the case of a fence, the effect of reducing air resistance is 20 to 30% lower than that of an optimally-shaped air differential. It has been confirmed from the results of actual running tests.

(3) Nose cones and air vanes have the same disadvantages as air differentials.

[0025]

According to the present invention, the upper surface is provided with a cap.
Equipped with a carrier or bodywork located higher than the roof of the
In a device for reducing the resistance of air received on the front surface of the cargo bed or bodywork on the truck obtained ,
On the front of the loading platform or bodywork located above the roof ,
A flat plate-shaped air guide plate extending forward at a position separated from the end edge by a predetermined distance toward the center is provided, and a flat plate bent toward the center by a predetermined angle at the front end of the air guide plate . This is one in which a bending portion is formed.

When the above-mentioned device is provided at the front of the truck bed, particularly at the upper end thereof, the bending portion is inclined obliquely downward. The airflow hitting the bent portion is guided forward of the upper edge of the front surface of the carrier according to the inclination. Then, the air is further pushed downward by the upper air flow, and the flow is changed along the upper surface of the carrier, so that the air flows smoothly along the upper surface of the carrier.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 truck equipped with an air resistance reducing device according to the present invention.

As shown in the figure, the truck 1 has a cab 2
Behind the box (van) type carrier 3 (object),
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. Bed height position H ₃ of the upper surface portion 3a of 3 is set at a position higher than the height position of H ₂ of the cab 2 roof (roof) 2a. As a result, the carrier 3 protrudes to a position higher than the cab roof 2a.

An air resistance reducing device 4 according to the present invention is arranged in a space above the roof 2a of the cab 2 and in front of the front surface 3b of the carrier 3. The air resistance reduction device 4
It mainly comprises a horizontal viscous flap 5 (wind guide plate) and a pair of vertical viscous flaps 6 (wind guide plate) extending forward from the loading platform front portion 3b.

Horizontal Visco Flaps
The us Flap (hereinafter referred to as HVF) 5 is integrally formed by bending a flat plate made of metal, resin, plastic, or the like. The HVF 5 is attached to the upper end of the loading platform front portion 3b and extends over the entire length thereof along the width direction of the loading platform 3, and its rear end is attached to the loading platform front portion 3b to form an attachment portion 5a. I do. As shown in FIG. 2, from the mounting portion 5a, it is bent forward at a substantially right angle,
As a result, a horizontal portion 5b continuous with the mounting portion 5a is integrally formed. The portion in front of the horizontal portion 5b is bent obliquely downward at a predetermined angle, whereby the bending portion 5c continuous with the horizontal portion 5b is formed integrally. The front-rear length or front-rear width of the mounting portion 5a, the horizontal portion 5b, and the bending portion 5c is constant along the width direction of the carrier.

Here, a method for determining the dimensions of the horizontal portion 5b and the refraction portion 5c will be described. Referring to FIG. 2, h is defined by the following equation, where H is the height of the loading platform 3, and h is the distance from the upper edge 3 d of the loading platform front surface 3 b to the rear end position of the horizontal portion 5 b.

[0033] from 0.05H <h <0.15H ... (1 ) (1) h which is determined by the formula, define the longitudinal length L ₁ of the horizontal portion 5b by the following equation.

1.1h ≦ L ₁ ≦ 1.8h (2) Here, the angle between the upper surface of the horizontal portion 5b and the front surface 3b of the loading platform is α (°), the front-rear length of the refraction portion 5c is L ₂ , The angle of inclination of the refraction portion 5c with respect to the horizontal portion 5b is β (°). 8 to 10 are graphs based on experimental results showing Cd reduction rates (ratio to Cd values of trucks without the device) ΔCd for each of L ₂ / L ₁ , α and β.

[0035] Figure 8 shows the relationship between L ₂ / L ₁ and? Cd, to stabilize over the next L ₂ / L ₁ is about 10% of Cd reduction effect as long as it is within the range of 0.7 to 1.1 I understand.
Thus, defined as follows the scope of the L ₂ / L _1.

0.7 ≦ L ₂ / L ₁ ≦ 1.1 (3) From this, the value of L ₂ is as follows.

0.7L ₁ ≦ L ₂ ≦ 1.1L ₁ (3 ′) However, it is not always necessary to set the range to this range, and there is a case where a good Cd reduction effect can be obtained outside this range. However, when a value outside this range is adopted, care must be taken because the value of ΔCd for various parameters changes rapidly.

Next, FIG. 9 shows the relationship between α and ΔCd. According to this, L ₂ / L ₁ is 0.7
It can be seen that the Cd reduction effect is stabilized at about 10% when α is in the range of 90 to 110 (°) within the range of 1.1. Therefore, the range of α is determined as follows.

90 ≦ α ≦ 110 (°) (4) Here, according to the graph, even when α is within the above range, ΔCd tends to slightly deteriorate near the upper limit and the lower limit. Therefore, based on the experimental result of α = 93 (°), the applicable range of β was determined in the graph shown in FIG. According to this graph, if β is in the range of 45 to 55 (°), sufficient C
It can be seen that the d reduction effect is obtained. Therefore, the range of β is determined as follows.

45 ≦ β ≦ 55 (°) (5) The above results were obtained by a wind tunnel experiment.
By determining the dimensions of the horizontal portion 5b and the refraction portion 5c based on the expressions (5), it is possible to obtain a stable and constant effect which is not so affected by the fluctuation of each parameter.

Next, FIG. 3 is a diagram showing a method of mounting the HVF 5 to the front surface portion 3b of the carrier. Stud bolts 11 are attached to the mounting portion 5a of the HVF 5 at predetermined intervals along the width direction of the carrier. I have. In addition, a bolt insertion hole 7 is provided in the front part 3b of the loading platform corresponding to the position of the stud bolt 11. The stud bolt 11 is inserted into the bolt insertion hole 7 via the outer packing 8 from the outside of the carrier 3, and the nut 10 is tightened from the inside of the carrier 3 via the inner packing 9, thereby fixing the HVF 5.

The configuration and dimensions of the above HVF 5 are described in the vertical viscous flap (Vertical Viscous Flap,
The same applies to (VVF) 6. That is, the VVF 6 is arranged so as to extend in the height direction by rotating the HVF 5 by 90 °, and has substantially the same configuration as that of the VVF 6 attached to both side ends of the front surface 3b of the loading platform. And VV
F6 is provided symmetrically on both sides of the loading platform front part 3b,
That is, the HVFs 5 are arranged such that the rotation directions of the HVFs 5 are opposite to each other. Therefore, VVF 6 is the mounting part 5 of HVF 5.
a, mounting portions 6a corresponding to the horizontal portion 5b and the bending portion 5c,
It has a vertical portion 6b and a refraction portion 6c.
Each VVF 6 is bent obliquely toward the center of the width of the bed 3. Since the bending portion 5c of the HVF 5 is bent toward the center of the height of the bed 3, each bending portion 5c, 6c
Will be refracted toward the center of the front surface 3b of the carrier, respectively. The distance v between the vertical part 6b and the side edge 3e of the loading platform front part 3b takes the same value as the above-mentioned h. The relationship between the length and angle of the vertical portion 6b and the refraction portion 6c is the same as in the case of the HVF 5.

In the present embodiment, the HVF 5 and the VVF 6 are combined in a cross-girder shape. Therefore, even if one of them is divided and made linear at the time of assembly, or both are integrally formed in a cross-girder shape. Good.

Next, the flow of air by the HVF 5 in the device 4 will be described.

As shown in FIG. 4, the air flow F ₁ flowing into the lower side of the horizontal flat plate in the conventional fence is HV
Since there is the refracting portion 5c of F5, the refracting portion 5c is blocked by the refracting portion 5c and is flipped up to flow obliquely upward. Then, a part thereof is separated at the connection point of the horizontal portion 5b and the bending portion 5c, and the horizontal portion 5b
A vortex S is generated in a space above the front side b and in front of the loading platform front part 3b. This vortex S generates a negative pressure and reduces the air resistance as in the case of the fence. On the other hand, the airflow F ₁ that is lift-up at the bent portion 5c is guided to the front than in conventional fence flat (f indicated by ₃₎ the angle setting of the refraction portion 5c, the upper air flow F than _At the position near the upper end edge 3d of the loading platform front surface 3b, the flow is changed in the horizontal direction, that is, along the loading platform upper surface 3a. Thus, generation of the peeling zone at bed upper surface 3a of the air flow F ₁ is prevented. The unsteady flow, which has been generated alternately between the upper side and the lower side of the horizontal flat plate in the related art, does not occur in the device 4 because all the air flow is guided to the refraction portion 5c.

The above air flow can also occur at the side of the loading platform 3. That is, as shown in FIG.
Refracting portion 6c of F 6 is an air flow F ₃ which has been opposed as with the refractive portion 5c of the HVF 5, smoothly guided without causing peeling along the surface of the cargo bed side portion 3c.

FIG. 11 shows a graph comparing the performance of the conventional device and the present device 4. As can be seen from the graph, in the case of the fence, the ΔCd value is considerably lower than that of the air differential (about 30%). In the case of the present device 4, the same performance as the air differential can be obtained.

As described above, according to the device 4, it is possible to eliminate the above-mentioned disadvantages 1 to 5 which have occurred in the conventional fence, and also to eliminate the disadvantage of the air differential because of the same structure as the fence. It is lightweight and inexpensive, is not restricted by the height of the carrier, and can be applied to all types of vehicles only by adjusting the length. In other words, the present device 4 can eliminate the disadvantages without impairing the advantages of the fence, and at the same time, can obtain performance equal to or higher than that of an air differential.

FIG. 6 shows a modified embodiment, in which one HVF 5 and two VVFs 6 are combined in a U-shape as a whole. Thus, HVF 5 and VVF
6 can be arbitrarily selected.

As shown in FIG. 7, when the present apparatus 4 is mounted on a specially mounted vehicle, it may be mounted on the front surface of the mounted body 12 in the same manner as described above. In this case,
Foregoing h is smaller than the height H ₁ of KaSobutsu 12.

Various other modified embodiments are conceivable, and the present invention is not limited to the above embodiments. Truck load
The table is not limited to a box-shaped table , but may be a column or a column, such as a liquid storage tank.

[0052]

The present invention exhibits the following excellent effects.

(1) Compared to a conventional air resistance reduction device, it is simple, small, light, inexpensive, and can achieve the same or better performance.

[Brief description of the drawings]

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

FIG. 2 is a side view showing the configuration of H.V.F.

FIG. 3 is an exploded longitudinal side view showing a method of mounting the HVF.

FIG. 4 is a side view showing the flow of air by H.V.F.

FIG. 5 is a plan view showing the flow of air by V.V.F.

FIG. 6 is a perspective view showing a modified embodiment.

FIG. 7 is a perspective view showing an application example of the present device to a specially equipped vehicle.

FIG. 8 is a graph based on an experimental result showing a relationship between L ₂ / L ₁ and a Cd reduction rate.

FIG. 9 is a graph based on experimental results showing the relationship between α and the Cd reduction rate.

FIG. 10 is a graph based on experimental results showing the relationship between β and the Cd reduction rate.

FIG. 11 is a graph for comparing the performance of the conventional apparatus and the present apparatus.

FIG. 12 is a side view showing the flow of air in a normal truck.

FIG. 13 is a perspective view showing a truck equipped with a conventional air resistance reducing device (air deflector).

FIG. 14 is a perspective view showing a truck equipped with a conventional air resistance reduction device (fence).

FIG. 15 is a perspective view showing a truck equipped with a conventional air resistance reducing device (nose cone).

FIG. 16 is a perspective view showing a truck equipped with a conventional air resistance reduction device (air vane).

FIG. 17 is a plan view showing the flow of air by an air deflector.

FIG. 18 is a side view showing a specially equipped vehicle.

FIG. 19 is a side view showing a flow of air by a fence.

[Explanation of symbols]

 3 Carrier (object) 3b Front (front) 3d Upper edge (edge) 3e Side edge (edge) 4 Air drag reduction device 5 Horizontal viscous flap (wind guide plate) 5c, 6c Refractor 6 Vertical viscous flap Wind guide plate) h, v distance

Claims (1)

(57) [Claims] 1. The upper surface is positioned higher than the cab roof.
On a truck with a carrier or bodywork
A device for reducing the resistance of air received on the front of a carrier or bodywork , wherein the device is located above the roof of the cab.
On the front surface of the loading table or bodywork , a flat plate-shaped air guide plate is provided which extends forward at a position separated from the edge by a predetermined distance toward the center, and a predetermined angle is provided at the front end of the air guide plate. An air resistance reduction device characterized in that a plate-shaped refraction portion refracted only toward the center is formed.