JP2000233767A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce drag without reducing space efficiency by arranging an almost quadrangular step at least in three edge parts of the whole car body surface of an almost quadrangular column shape such as an automobile and an electric railcar. SOLUTION: An almost quadrangular swelling of a similar shape to the front face shape is arranged in front and in rear of a car body 11 formed in a box shape of an almost quadrangular column shape (a rectangular solid shape for setting the longitudinal direction in the lengthwise direction) so that the front face shape of the car body 11 is formed in a stepped shape having a step 12 in four edge parts of the upper/lower edges and left/right both side edges. In this case, the front outside edge of the car body 11 and the step 12 is set to a sharp edge angle, that is, an unchamfered right angle. Thus, the step is arranged on a car body front face of a quadrangular column shape such as an electric railcar and a bus and a cargo box front face of a quadrangular column shape mounted on a truck to reduce drag without reducing space efficiency. The drag reducing effect is almost the same even when a wind speed changes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a box-shaped vehicle such as a truck, a bus or a train, and more particularly to a device for reducing air resistance (drag).

[0002]

2. Description of the Related Art In general, it has been found that in order to reduce the air resistance of a vehicle body when the vehicle is running, it is desirable to reduce the resistance coefficient thereof. I have. However, if you make it streamlined,
Space efficiency is reduced due to restrictions on the body shape.
For this reason, for example, in the case of a truck in which a cargo box is mounted so as to protrude upward from the roof of the driver's cab, an air deflector (baffle plate) is attached to the roof of the driver's cab, and the cargo box section is mounted without lowering space efficiency. The air resistance is reduced. Further, in the case of a bus, although the air resistance is reduced by making the outer edge of the vehicle body a curved surface in order to give priority to space efficiency, a box type is generally used. Furthermore, in the case of a train, the front shape of the Shinkansen is streamlined, but many other trains such as subways have a box shape that gives priority to space efficiency.

[0003]

For example, in the case of an existing roof deflector used for a truck, the shape is a curved shape for preventing the "separation" of the air flow, which is complicated and cumbersome to manufacture. . In addition, there is a problem that the structure must be such as to secure sufficient mounting strength. On the other hand, in the case of general vehicles such as buses and subways, space efficiency is prioritized and air resistance is large. In addition, on engineering, as a result of conducting a wind tunnel experiment on the flow of air around the axial flow cylinder when providing a step-shaped step around the front of the axial flow cylinder, the axial drag was reduced with respect to the cylinder without step, Despite the report, this is only a report on basic experiments on fluid dynamics using a cylinder, and there is no concrete report on the possibility of application to an actual vehicle.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to apply the above-described principle to a vehicle such as an automobile or a train without reducing space efficiency. It is an object of the present invention to provide a shape in front of a vehicle such as an automobile or a train that can reduce drag.

[0005]

To achieve the above object, the following means are taken. In the following description, the height of the step means the distance from the outer surface of the vehicle body or the outer surface of the carton to the outer surface of the step, and the length of the step means the distance from the front surface of the vehicle body or the front of the carton to the front surface of the step (step protrusion amount). ). According to a first aspect of the present invention, there is provided a vehicle having a substantially quadrangular prism-shaped vehicle body, wherein a substantially square step is provided on at least three edges of the front surface of the vehicle body. According to the invention of claim 1 having such a configuration, it has been found from the experimental results that the drag can be reduced as compared with a flat-headed quadrangular prism-shaped vehicle body without steps. The drag reduction effect is almost the same even when the wind speed changes.

According to a second aspect of the present invention, there is provided a truck having a substantially quadrangular prism-shaped packing box having a protruding portion higher than the upper surface of a driver's seat, wherein at least three edges of a front surface of the protruding portion have a substantially rectangular shape. A step is provided. According to the second aspect of the invention having such a configuration, it has been found from the experimental results that the effect of reducing the drag is substantially proportional to the ratio of the amount of protrusion of the packing box from above the driver's seat (the roof upper surface). And
Drag can be reduced compared to a flat head without steps. In addition, it is possible to obtain a slightly better drag reduction effect than in the case of a vehicle with a roof deflector.

Further, the invention according to claim 3 is a structure used for a truck having a substantially quadrangular prism-shaped packing box having a protruding height higher than the upper surface of a driver's seat, which can be mounted on the front face of the packing box. And a substantially square base provided on at least three edges of the front surface of the base. Since the truck structure having such a configuration can be attached to the front surface of the substantially rectangular pillar-shaped packing box in a retrofitted form, it can be applied to a packing box mounted on an existing truck. In this case, in general, the outer edge of the front surface of the packing box is often a chamfered structure with a curved surface. However, by providing a structure with a base that can be retrofitted, the desired drag reduction effect can be obtained.

When a step is provided on the front surface of the projecting portion of the truck packing box and the ratio of the length of the step to the height of the step is set to a range of more than 0 and less than 2, an effective drag reduction effect is obtained from experimental results. It was found that when the ratio of the length to the height of the step was set in the range of 1 to 1.4, an optimal drag reduction effect could be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. The first embodiment corresponds to the first aspect of the present invention. As shown in FIG. 1, this is a case where the present invention is applied to a train and a bus, and a front surface of a substantially rectangular prism-shaped (a rectangular parallelepiped shape whose longitudinal direction is the front-rear direction) box-shaped body 11 is similar to the front shape. By providing a substantially quadrangular bulge, the front surface shape of the vehicle body 11 is formed into a shape having steps 12 (stepped) at four edges, that is, upper and lower edges and left and right side edges. In this case, the outer edges of the front surfaces of the vehicle body 11 and the step 12 are pin angles,
That is, it is set at a right angle without chamfering.

FIG. 2 shows a vehicle body 11 and a step 12.
Are shown, and the description of the symbols is as described in the drawings. The dimensional relationship of the step portion is set as follows. In the present embodiment, step 12
(The distance from the outer surface of the vehicle body to the outer surface of the step) h is set as follows: h = 0.1r0 = 0.1d0 / 2, (r = 0.9r0, d = 0.9d0) The length (distance from the front of the vehicle body to the front of the step) Sx is set to Sx = 1.33h and (step ratio SR = Sx / h = 1.33). As described above, in the present embodiment, the substantially square step 12 is provided on the front surface of the vehicle body 11, and the dimensional relationship of the step portion is set as described above, so that the space efficiency is not reduced. ,
Experimental results show that drag can be reduced.

Hereinafter, a wind tunnel experiment performed using the model will be described. In the wind tunnel experiment, a model was prepared by attaching a step (flat plate) having a square shape of 182 mm in length and width with different step lengths Sx to the front of a square prism of 200 mm in length and 500 mm in length and 500 mm in length, and a flat square prism with no step. , And the wind speed U was changed in units of 5 m / s in the range of 10 m / s to 35 m / s. FIG. 3 is a table showing the drag coefficient with respect to the step ratio, FIG. 4 is the same graph, and FIG. 5 is a graph showing the relationship between the wind speed U and the drag coefficient CD.

Here, D is defined as the axial flow square column drag (kg ·
f), where CD is the drag coefficient, q is the main flow dynamic pressure, ρ is the air density (kg / m3), U is the main flow velocity (m / s), and A is the surface area, and D = CD · q · A. , Q = ρ · U2 / 2. According to the experimental data, as shown in FIGS. 3 and 4, in the case of the stepped model, the drag coefficient CD is reduced in the range of the step ratio from 0 to less than 2 with respect to the flat head. The degree is small. Further, a high reduction effect is recognized in the range of the step ratio SR = 1 to 1.4, and particularly when the step ratio SR is 1.33, the drag coefficient C is large.
D is the minimum (0.42 at wind speeds of 15 m / s, 20 m / s, and 35 m / s, respectively). Therefore, the drag D at the optimum step ratio SR = 1.33 is about 1/2 of the flat head.
It can be reduced to. Further, as shown in FIG. 5, substantially the same stable reduction effect is recognized even when the wind speed U changes.

Next, a second embodiment of the present invention will be described with reference to FIG. This second embodiment is described in claim 2
The present invention is applied to a box-shaped packing box 21 mounted on a truck.
In this case, the cargo box 21 is one that protrudes above the upper surface (roof) of the cab 23. Therefore, in this embodiment, the upper portion of the front surface of the packing box 21 formed in a substantially quadrangular prism shape (a rectangular parallelepiped shape whose longitudinal direction is the front-rear direction), that is, the front surface protruding upward from the upper surface height of the cab 23 is provided. By providing a substantially square bulge similar to the front shape, the front shape of the packing box 21 is formed into a shape having substantially square steps 22 at three edges of the upper edge and the left and right side edges.

In this case, the dimensional relationships of the steps are basically the same as those of the train of the first embodiment, and are set as follows. The step height h is
h = 0.1r0 = 0.1d0 / 2, and the step length Sx is Sx = 1.33h, (SR = Sx / h
= 1.33). However, d0 takes the full width of the packing box.
In addition, regarding the length below the step 22, the cab 23
(The protrusion amount i of the packing box 21) up to the upper end of the roof.
From the experimental results, it was found that the drag can be reduced without lowering the space efficiency even when using the truck according to the second embodiment having the above-described configuration.

Hereinafter, a wind tunnel experiment according to the second embodiment will be described. In the experiment, two models with different protrusion amounts i0 from the upper surface of the driver's seat of the truck are mounted while being separated from the rear surface of the driver's seat, and are compared with "flat head" without steps and "deflector mounting" on the cab roof. It was carried out in the form.

"Experiment 1" Using a model in which the amount of protrusion i0 of the packing box 21 from the upper surface of the driver's seat 23 as shown in FIG. 7 is 80 mm, the optimum step ratio SR = 1.33, and changing the packing box condition. Carried out. Here, the form shown in (A) in which the step 22 is provided on the entire front surface of the packing box 21 is the basic type, and the packing box condition is that the step 22 is provided only on the protruding surface of the packing box front surface from the upper surface of the driver's seat. (B), and the condition of the packing box section is the form as shown in (C), in which the gap between the rear surface of the cab and the front surface of the packing box is closed.

According to the above experimental data, the step ratio SR
As is clear from FIG. 8 showing the drag coefficient CD with respect to the table and FIG. 9 showing the graph, the drag coefficient CD is reduced by about 20% with respect to the flat head with the step. In other words, in the case with a step, about 1
There is a drag reduction effect of a little over / 5. In the case of the condition with the packing box portion, the drag coefficient CD is almost the same as that of the basic type. That is, step 22 is applied only to the projecting surface on the front of the packing box.
It can be confirmed that the drag reduction effect can be obtained by providing. Also, the effect of reducing the drag is greater for the deflector mounting.

[Experiment 2] A model in which the amount of protrusion i0 of the packing box 21 from the upper surface of the driver's seat 23 as shown in FIG. 10 was 135 mm was used at an optimum step ratio SR = 1.33. In the case of Experiment 2, the drag coefficient CD with respect to the optimal step ratio SR was shown in a table of FIG. 11 and a graph of FIG.
As can be seen from the figure, a drag reduction effect of about 1/3 was observed for the flat head, and about 15% for the deflector mounting.
The effect of reducing the drag was observed.

As described above, when the step 22 is provided on the front surface of the packing box 21 of the truck, a large drag reduction effect can be obtained as compared with a flat head without a step, and a little more than when a deflector is attached. An excellent drag reduction effect can be obtained. Based on a comparison between Experiment 1 and Experiment 2, the drag reduction effect is considered to be substantially proportional to the protrusion amount i0 of the packing box 21 from above the driver's seat (the roof upper surface).

Next, a third embodiment will be described with reference to FIGS. This embodiment corresponds to the invention described in claim 3 and comprises a step structure 31 with a base which can be retrofitted on the front surface of a packing box 35 (shown by a virtual line) of a truck. It is. The step structure 31 includes a square base 32 corresponding to the front shape of the packing box 35 projecting from the upper surface of the driver's seat, and a square step 33 formed to project from the front surface of the base 32, By mounting this on the front surface of the packing box 35, the front shape of the packing box 35 can be formed into a shape having square steps 32 at three edges, that is, the upper edge and the left and right side edges. This step structure 31
It is formed by styrofoam, resin or metal pressed product.

As shown in FIG. 14, the dimensional relationship in this case is determined according to the above-described second embodiment, and the dimensions of each part relating to the base 32 are determined by replacing the packing box 21. Therefore, when the step structure 31 is set in the same dimensional relationship as that of the second embodiment and is attached to the front surface of the truck packing box, the same operation and effect as those of the second embodiment can be achieved. Can be. For example, Step 3
If the ratio SR of the length SX to the height h of 2 is set to a range exceeding 0 and less than 2, an effective drag reduction effect can be obtained, and the length SX of the step SX to the height h of the step can be obtained. When the ratio SR is set in the range of 1 to 1.4,
The optimal drag reduction effect can be obtained. Generally, the outer edge of the front surface of the existing packing box is chamfered by a curved surface. Therefore, a step structure 31 including a base 32 and a step 33 as in the present embodiment is provided. By doing so, it is possible to effectively cope with the packing box having the chamfered structure as described above. When the front shape of the packing box is not completely flat, the shape of the mounting surface 32 a of the base 32 is set to correspond to the front shape of the packing box 35.

Although the embodiment has been described only with respect to the front shape of the vehicle body and the packing box, the invention can also be applied to the side surface.

[0023]

As described in detail above, according to the present invention,
By providing steps on the front surface of a rectangular pillar-shaped vehicle body such as a train or a bus or on the front surface of a rectangular pillar-shaped packing box mounted on a truck, drag can be reduced without lowering space efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a vehicle according to a first embodiment of the present invention.

FIGS. 2A and 2B are explanatory views of a vehicle body, steps, and dimensions of each part according to the first embodiment, wherein FIG. 2A is a front view and FIG.

FIG. 3 is a table showing a relationship between a step ratio and a drag coefficient based on an experimental example corresponding to the first embodiment.

FIG. 4 is a graph showing a relationship between a step ratio and a drag coefficient.

FIG. 5 is a graph showing the relationship between wind speed and drag.

FIG. 6 is an explanatory diagram showing a second embodiment.

FIGS. 7A and 7B are explanatory diagrams of a model form of Experimental Example 1 according to the second embodiment, in which FIG. 7A shows no packing box condition, and FIGS. 7B and 7C show packing box conditions, respectively.

FIG. 8 is a table showing a relationship between a step ratio and a drag coefficient based on Experimental Example 1.

FIG. 9 is a graph showing the relationship between wind speed and drag coefficient.

10A and 10B are explanatory diagrams of a model form of Experimental Example 2 according to the second embodiment, where FIG. 10A shows a case of a flat head and FIG.
Indicates the deflector mounting, and (C) indicates the optimal step.

11 is a table showing a relationship between a step ratio and an efficacy coefficient based on Experimental Example 2. FIG.

FIG. 12 is a graph showing the relationship between the wind speed and the drag coefficient.

FIG. 13 is a perspective view showing a third embodiment.

14A and 14B are explanatory diagrams of dimensions of each part of a step structure according to the third embodiment, where FIG. 14A is a front view and FIG. 14B is a plan view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Body 12 ... Step 21 ... Packing box 22 ... Step 31 ... Step structure 32 ... Base 33 ... Step

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[Procedure amendment]

[Submission date] December 21, 1999 (1999.12.
21)

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[Title of the Invention] vehicle

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[0005]

To achieve the above object, the following means are taken. In the following description, the height of the step means the distance from the outer surface of the vehicle body or the outer surface of the carton to the outer surface of the step, and the length of the step means the distance from the front surface of the vehicle body or the front of the carton to the front surface of the step (step protrusion amount). ). The invention according to claim 1 is a vehicle having a substantially quadrangular prism-shaped vehicle body , wherein a part of the front surface of the vehicle body is located at the front.
To at least three edges of the front of the vehicle body.
A step is formed . According to the invention of claim 1 having such a configuration, it has been found from the experimental results that the drag can be reduced as compared with a flat-headed quadrangular prism-shaped vehicle body without steps. The drag reduction effect is almost the same even when the wind speed changes.

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According to a second aspect of the present invention, there is provided a truck having a substantially rectangular column-shaped packing box having a protruding portion higher than the upper surface of a driver's seat, wherein a part of the front surface of the protruding portion is extended forward.
Steps on at least three edges of the front of the projection
It is characterized in that form. According to the second aspect of the invention having such a configuration, it has been found from the experimental results that the effect of reducing the drag is substantially proportional to the ratio of the amount of protrusion of the packing box from above the driver's seat (the roof upper surface). And the drag can be reduced as compared with the flat head without step. In addition, it is possible to obtain a slightly better drag reduction effect than in the case of a vehicle with a roof deflector.

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Hereinafter, a wind tunnel experiment performed using the model will be described. In the wind tunnel experiment, a step was formed on the front surface of a square prism of 200 mm in length and width and 500 mm in length .
For the sake of convenience, a model in which step shaped bodies (plates) of 182 mm in length and width and having different step lengths Sx are affixed as a model is used for convenience, and the wind speed U is determined for 12 types including a flat square prism having no step. 1 in 5m / s increments
The measurement was performed in a range of 0 m / s to 35 m / s. FIG. 3 is a table showing the drag coefficient with respect to the step ratio, FIG. 4 is the same graph, and FIG. 5 is a view showing the relationship between the wind speed U and the drag coefficient CD.

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Next, a third embodiment will be described with reference to FIGS. This embodiment is obtained by constituting the base with step structure 31 which can be retrofitted to the front of the track of the crates 35 (shown in phantom). The step structure 31 includes a square base 32 corresponding to the front shape of the cargo box 35 projecting from the driver's seat upper surface, and a square base 32 formed to project from the front surface of the base 32 .
And a packing 35
The front shape of the packing box 35 by attaching to the front of the
A shape having square steps at the upper edge and the left and right side edges may be used. This step structure 31
Is formed of styrofoam, resin, a metal pressed product, or the like.

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As shown in FIG. 14, the dimensional relationship in this case is determined according to the above-described second embodiment, and the dimensions of each part relating to the base 32 are determined by replacing the packing box 21. Therefore, when the step structure 31 is set in the same dimensional relationship as that of the second embodiment and is attached to the front surface of the truck packing box, the same operation and effect as those of the second embodiment can be achieved. Can be. For example, by setting the ratio S _R a range of less than 2 over a 0 length S _X for <br/> height h of steps, it will be able to obtain an effective drag reducing effect, also, step S _X for height h
When the ratio S _R is set in the range of ₁ to 1.4, an optimum drag reduction effect can be obtained. The outer edge of the front surface of the existing packing box is generally chamfered by a curved surface. Therefore, a step structure 31 composed of a base 32 and a step molded body 33 as in this embodiment is used. Is provided, it is possible to effectively cope with the packing box having the chamfered structure as described above. When the front shape of the packing box is not completely flat, the shape of the mounting surface 32 a of the base 32 is set to correspond to the front shape of the packing box 35.

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[Description of Signs] 11 ... Car body 12 ... Step 21 ... Packing box 22 ... Step 31 ... Step structure 32 ... Base 33 ... Step molded body

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 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nobuhiko Kamiya 4-213-501 Hirako Asadacho, Nisshin-shi, Aichi F-term (reference) 3D003 AA16 BB09 BB10 CA02 DA01

Claims (5)

[Claims] 1. A vehicle having a substantially quadrangular prism-shaped vehicle body, wherein at least three edges of a front surface of the vehicle body are provided with substantially square steps. 2. A truck having a substantially quadrangular prism-shaped packing box having a protruding portion higher than the upper surface of a driver's seat, wherein at least three edges of a front surface of the protruding portion are provided with substantially quadrangular steps. 3. A structure used for a truck having a substantially quadrangular prism-shaped packing box having a protruding portion higher than the upper surface of a driver's seat, comprising: a substantially square base mountable on a front surface of the protruding portion; A substantially rectangular step provided on at least three edges of the front surface of the base. 4. The truck of claim 2 wherein the ratio of length to step height is greater than zero and less than two. 5. The ratio of the length to the height of the step is 1 to 5.
3. The truck according to claim 2, wherein the ratio is 1.4.