JP6747089B2 - Wind tunnel test method for automobile and method for manufacturing tire model for wind tunnel test - Google Patents

Description

The present invention relates to a wind tunnel test method for an automobile and a method for producing a tire model used therefor, and more specifically, a wind tunnel test method for an automobile and a wind tunnel test tire capable of reproducing various tire shapes at low cost. Regarding the method of making a model.

Generally, the force (air resistance or lift) received from the air by a moving vehicle increases in proportion to the square of the speed. Therefore, for example, most of the engine output is used to overcome the air resistance during high-speed traveling, which leads to deterioration of fuel efficiency. Such air resistance and lift change according to the vehicle body shape and tire shape of the automobile. Therefore, it is important to evaluate air resistance and lift that change according to the vehicle body shape and tire shape of an automobile prior to commercialization of the automobile (see, for example, Patent Documents 1 and 2).

When measuring the air resistance and lift of an automobile, a wind tunnel test using a model scaled down to 1/2 to 1/5 of that of an actual automobile is being conducted. In such a wind tunnel test, an automobile body model and a tire model are placed on an annular belt in a combined state so as to have a predetermined arrangement relationship, and the annular belt is driven to roll the tire model onto the annular belt. While moving, air is made to flow from the front side to the rear side of the automobile in the space on the annular belt, and the forces acting on the vehicle body model and the tire model are measured as the air flows.

Here, in order to confirm the aerodynamic effect based on the tire shape, it is necessary to manufacture many types of tire models having different tire shapes. Therefore, when trying to confirm the aerodynamic effect for various tire shapes, there is a problem that the manufacturing cost of the tire model increases.

Japanese Patent No. 3147589 Japanese Patent No. 3716158

An object of the present invention is to provide a wind tunnel test method for an automobile and a method for manufacturing a tire model for a wind tunnel test, capable of reproducing various tire shapes at low cost.

The automobile wind tunnel test method of the present invention for achieving the above object is to arrange the vehicle body model and the tire model of the automobile on an annular belt, and drive the annular belt to drive the tire model to the annular belt. While rolling, air is made to flow from the front side to the rear side of the automobile in the space on the annular belt, and acts on each of the vehicle body model and the tire model as the air flows. In the wind tunnel test method of the car that measures the force,
The tire model is composed of a plurality of divided parts divided in the tire width direction, a plurality of types of replaceable parts having different shapes are prepared as at least one divided part, and any replaceable part selected from them is included. The tire model is manufactured by combining the plurality of divided parts with each other, and the force is measured using the tire model.

Further, a method for producing a wind tunnel test tire model of the present invention for achieving the above object is a method for producing a tire model used for a wind tunnel test of an automobile, wherein the tire model is divided in the tire width direction. A plurality of types of replaceable parts each having a different shape as at least one separate part, and the plurality of separate parts including any replaceable part selected therefrom are combined with each other to form a tire. It is characterized by making a model.

In the present invention, when performing a wind tunnel test of an automobile, a tire model is composed of a plurality of divided parts divided in the tire width direction, and a plurality of types of replaceable parts having different shapes are prepared as at least one divided part. A tire model is manufactured by combining a plurality of split parts including any replaceable parts selected from the above, and the force acting on each of the car body model and the tire model is measured by using the tire model with the flow of air. Therefore, it is possible to appropriately change the tire shape based on the combination of the divided parts while suppressing the manufacturing cost of the tire model. Therefore, various tire shapes can be reproduced at low cost.

In the present invention, it is preferable that the plurality of divided parts have concave portions and convex portions that are in meshing relation with each other, and that the plurality of divided components be combined with each other while the concave portions and the convex portions are engaged with each other. As a result, the accuracy with which the divided parts are joined together is improved, so that the accuracy with which the shape is reproduced when the joining and disassembly of these divided parts are repeated is improved, and as a result, the measurement accuracy in the wind tunnel test of the automobile can be increased.

Further, it is preferable that the tire model has a hollow portion formed inside thereof in a state where a plurality of divided parts are joined. In this case, the material cost can be reduced. Moreover, by reducing the weight of the tire model, the impact due to the vibration of the tire model during the wind tunnel test can be reduced, and as a result, the durability of the tire model and the wind tunnel test equipment can be improved.

1 is a perspective view showing a wind tunnel test apparatus for an automobile according to the present invention. It is a perspective view which shows the manufacturing method of the tire model for a wind tunnel test which concerns on this invention. It is a perspective view which shows the modification of the tire model obtained by this invention. It is a perspective view showing the division parts of the tire model obtained by the present invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an automobile wind tunnel test apparatus according to the present invention. In FIG. 1, a vehicle body model 1 and a tire model 2 of an automobile are arranged on an annular belt 3 in such a state that they are not connected to each other but are combined so as to have a normal positional relationship in the automobile. The vehicle body model 1 and the tire model 2 have the shapes of the vehicle body and the tire to be tested, and are scaled down to, for example, 1/2 to 1/5 of the actual size. The annular belt 3 has an endless structure wound around a pair of pulleys, and as shown in the figure, a portion exposed on the road surface is configured to continuously move from the front side to the rear side of the vehicle body model 1. There is.

The vehicle body model 1 is supported by wires 4 extending from the front and is also supported by three wires 5 extending from above, and a load detection device (not shown) connected to each of these wires 4 and 5 is a vehicle body model. The force acting on 1 is measured. On the other hand, each tire model 2 is supported by a support rod 6 extending from the side, and a load detection device (not shown) connected to this support rod 6 measures the force acting on each tire model 2. There is. An air supply device (not shown) is arranged on the front side of the vehicle body model 1.

When performing a wind tunnel test using the wind tunnel test apparatus for an automobile configured as described above, while driving the annular belt 3 to roll the tire model 2 with respect to the annular belt 3, the automobile in the space above the annular belt 3 Air is made to flow from the front side to the rear side to reproduce the running state of the automobile, and in that state, the force acting on each of the vehicle body model 1 and the tire model 2 is measured as the air flows. Thereby, the aerodynamic effect based on the specific vehicle body shape and the aerodynamic effect based on the specific tire shape can be confirmed.

In such a wind tunnel test, in order to confirm the aerodynamic effect based on the tire shape in detail, it is necessary to manufacture many types of tire models 2 having different tire shapes. However, when a large number of types of tire models 2 are individually manufactured, the manufacturing cost increases. Therefore, the tire model 2 is manufactured based on the following method.

FIG. 2 shows a method of manufacturing a wind tunnel test tire model according to the present invention. As shown in FIG. 2, when manufacturing a tire model 2 used for a wind tunnel test of an automobile, the tire model 2 is composed of a plurality of divided parts 21, 22, 23 divided in the tire width direction. In the example of FIG. 2, the tire model 2 includes a disc-shaped divided component 21 arranged inside the vehicle, a disc-shaped divided component 22 arranged at the center in the tire width direction, and a disc-shaped divided component arranged outside the vehicle. It is composed of divided parts 23. Here, a plurality of types of replaceable parts 23A and 23B having different shapes are prepared as the split parts 23 arranged outside the vehicle. For example, the replaceable component 23A includes a plurality of fins 31A extending in the tire radial direction at the sidewall portion and protruding from the surface of the sidewall portion. On the other hand, the replaceable part 23B includes a plurality of fins 31B extending in the sidewall portion while inclining with respect to the tire circumferential direction and projecting from the surface of the sidewall portion. Then, the tire model 2 is manufactured by combining the plurality of divided parts 21 to 23 so as to include any one selected from the plurality of types of replaceable parts 23A and 23B. A plurality of bolt holes 32 are formed at corresponding positions in each of the divided parts 21 to 23, and the bolt holes 32 are used to fix the bolts to each other.

When performing a wind tunnel test of an automobile as described above, the tire model 2 is composed of a plurality of divided parts 21 to 23 divided in the tire width direction, and a plurality of types of replaceable parts having different shapes as at least one divided part 23 23A, 23B are prepared, a plurality of split parts 21 to 23 including arbitrary replaceable parts 23A or 23B selected from them are combined with each other to manufacture a tire model 2, and the tire model 2 is used to flow air. The force acting on each of the vehicle body model 1 and the tire model 2 is measured accordingly, so that the tire shape can be appropriately changed based on the combination of the divided parts 21 to 23 while suppressing the manufacturing cost of the tire model 2. You can As a result, various tire shapes can be reproduced at low cost.

In the above-described embodiment, a plurality of types of replaceable parts 23A and 23B having different shapes are prepared as the split parts 23 arranged on the outside of the vehicle, but, for example, a disc-shaped split part arranged in the center in the tire width direction. It is also possible to prepare a plurality of types of replaceable parts having different shapes as 22. More specifically, when a plurality of types of replaceable parts having different widths are prepared as the split parts 22 arranged at the center in the tire width direction, the profile of the tire model 2 can be easily changed.

FIG. 3 shows a modified example of the tire model obtained by the present invention. In FIG. 3, the tire model 2 includes a disc-shaped divided component 21 arranged inside the vehicle, a disc-shaped divided component 22 arranged at the center in the tire width direction, and a disc-shaped divided component arranged outside the vehicle. 23, and a split component 24 that constitutes a portion corresponding to the sidewall portion outside the vehicle. Thus, the tire model 2 can be divided into any number along the tire width direction. As the divided part 24, a plurality of types of replaceable parts having different surface shapes can be prepared. In this case, in the tire model 2, the wind tunnel test can be effectively carried out in a form in which only the protrusions such as fins and letters formed on the surface of the sidewall portion are different.

FIG. 4 shows the divided parts of the tire model obtained by the present invention. As shown in FIG. 4, a recess 33 (through hole) is formed at the center of the mating surface of the split component 21, and an annular projection 34 is formed at the peripheral edge of the mating surface of the split component 21. On the other hand, at the center position of the mating surface of the split component 22, a convex portion 35 that is in mesh with the recess 33 of the split component 21 is formed, and at the peripheral portion of the mating surface of the split component 22, the convex portion of the split component 21 is formed. A concave portion 36 is formed so as to mesh with the concave portion 34. When a plurality of divided parts 21, 22 are combined with each other while the concave parts 33, 36 and the convex parts 34, 35 are engaged with each other, the joining accuracy of the divided parts 21, 22 is improved. The shape reproduction accuracy is improved when bonding and disassembling are repeated. As a result, the measurement accuracy in the wind tunnel test of the automobile can be improved.

Although FIG. 4 illustrates the connecting structure of the divided parts 21 and 22, such a connecting structure can be appropriately formed in a pair of adjacent divided parts. It is also possible to form a convex portion having a male screw portion on one of the divided parts and form a concave portion having a female screw portion on the other and screw them together.

As shown in FIG. 4, a plurality of hollow portions 37 are formed between the central portion and the peripheral portion of the split component 22. Although these cavities 37 are not exposed to the outside in the state where the tire model 2 is completed by combining the plurality of divided parts 21 to 23, the cavity part 37 is formed on the tire model 2 in the state where the plurality of divided parts 21 to 23 are connected. It is inherent. When the tire model 2 has the hollow portion 37 formed therein, the material cost can be reduced. Further, by reducing the weight of the tire model 2, it is possible to reduce the impact due to the vibration of the tire model 2 during the wind tunnel test, and as a result, it is possible to improve the durability of the tire model 2 and the wind tunnel test equipment. When the tire model 2 is integrated, it is difficult to form the cavity 37 as described above. However, by forming the tire model 2 into an assembly composed of a plurality of divided parts 21 to 23, as described above. The hollow portion 37 can be easily formed.

The material of the tire model 2 described above is not particularly limited, but examples thereof include resins such as polycarbonate resin and Delrin resin, as well as gypsum, laminated paper, and metal. In particular, it is preferable to use a resin from the viewpoint of workability, durability and lightness.

Further, the method of processing the divided parts constituting the tire model 2 is not particularly limited, but examples thereof include shaving with a machine tool (MC) and molding with a 3D printer using resin or metal as a raw material. You can As a method of connecting the divided parts to each other, besides the above-described bolt fixing, adhesion with an adhesive tape or the like can be mentioned. The bolt fixing is most preferable as a connecting method because the divided parts can be repeatedly connected and disassembled and the divided parts can be firmly connected.

1 Body Model 2 Tire Model 3 Annular Belt 4,5 Wire 6 Support Rods 21, 22, 23, 24 Split Parts 23A, 23B Replaceable Parts 31A, 31B Fins 32 Bolt Holes 33, 36 Recesses 34, 35 Convex Section 37 Cavity Section

Claims (6)

The vehicle model and the tire model of the automobile are arranged on the annular belt in a combined state, and while driving the annular belt to roll the tire model with respect to the annular belt, the automobile in the space above the annular belt In a wind tunnel test method for an automobile, in which air is caused to flow from the front side toward the rear side, and the force acting on each of the vehicle body model and the tire model is measured with the flow of the air,
The tire model is composed of a plurality of divided parts divided in the tire width direction, a plurality of types of replaceable parts having different shapes are prepared as at least one divided part, and any replaceable part selected from them is included. A wind tunnel test method for an automobile, comprising manufacturing a tire model by combining the plurality of divided parts with each other, and measuring the force using the tire model. 2. The automobile according to claim 1, wherein the plurality of divided parts have recesses and protrusions that are in mesh with each other, and the plurality of divided parts are combined with each other in a state where the recesses and the protrusions are engaged with each other. Wind tunnel test method. The wind tunnel test method for an automobile according to claim 1 or 2, wherein the tire model has a hollow portion formed inside thereof in a state in which the plurality of divided parts are combined. A method of manufacturing a tire model used for a wind tunnel test of an automobile, comprising the tire model composed of a plurality of divided parts divided in a tire width direction, and a plurality of types of exchange having different shapes as at least one divided part. A method for producing a tire model for a wind tunnel, comprising preparing a feasible part, and combining the plurality of divided parts including arbitrary replaceable parts selected from the feasible part with each other to manufacture a tire model. 5. The wind tunnel according to claim 4, wherein the plurality of divided parts have a concave portion and a convex portion that mesh with each other, and the plurality of divided components are combined with each other in a state where the concave portions and the convex portions are meshed with each other. How to make a test tire model. The method for manufacturing a tire model for a wind tunnel according to claim 4 or 5, wherein the tire model has a cavity formed inside thereof in a state where the plurality of divided parts are combined.

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