JP3147589B2 - Wind tunnel test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind tunnel test apparatus for measuring wind force and the like by applying wind to a vehicle.

[0002]

2. Description of the Related Art In general, the force that a moving vehicle receives from the air (hereinafter referred to as aerodynamic force) increases in proportion to the square of the speed. Therefore, during high-speed running, most of the output of the engine is used to overcome air resistance, and a large amount of fuel is consumed. The biggest factor that affects the aerodynamic force is the shape of the vehicle body, and the unevenness of the vehicle body changes the speed and direction of the air flow, and the aerodynamic force changes accordingly. Therefore,
In order to improve the performance and economy of vehicles, it is increasingly important to evaluate the aerodynamic force based on the shape of the vehicle before commercialization.

[0003] As a method of evaluating aerodynamic force, a wind tunnel experimental device has been conventionally used. Normally, when a certain amount of wind acts on the vehicle to be measured in the wind tunnel experimental device, a positive pressure portion 28 and a negative pressure portion 29 are formed on the surface of the vehicle to be measured as shown in FIG. The measured vehicle 11 is displaced in the vertical direction. Further, when the measured vehicle 11 is displaced in the vertical direction (the vehicle attitude is changed), the distribution of the positive pressure portion 28 and the negative pressure portion 29 is changed, the aerodynamic force is changed, and the measured vehicle 11 is displaced.
Thereafter, this phenomenon is repeated at a constant cycle, and appears on the measured vehicle 11 as minute vertical vibration. Note that the phenomenon of the minute vertical vibration may occur depending on the shape of the vehicle during actual traveling. Therefore, it is necessary to simulate this phenomenon with a wind tunnel experimental device before commercializing the product, preferably at the design stage.

FIG. 5 shows an example of a conventional wind tunnel experimental apparatus. The vehicle 11 to be measured is put on a movable belt-like floor surface 33, and is evaluated while being fixedly supported by a wind tunnel experimental device with a tire support rod 30, a back support rod 31, a suspension line 32, and the like. During operation of the wind tunnel test apparatus, the belt-like floor surface 33 is moved and the tires of the measured vehicle 11 are rotated in order to reproduce the actual running state. When a wind (arrow W) acts on the measured vehicle 11, an aerodynamic force is generated in the measured vehicle, and the measured vehicle 11 is vertically displaced. The aerodynamic force is measured by detecting, with the load measuring device 34, a distortion when the aerodynamic force is generated in the measured vehicle 11 and the cable 32 is pulled by the measured vehicle 11 .

[0005]

The "aerodynamic force-time" when a wind is applied to the vehicle 11 to be measured by the wind tunnel test apparatus described above.
FIG. 6 shows an example of the characteristic and the “displacement-time” characteristic. According to this, the wind to the measured vehicle 11 is changed from no wind to a certain amount (t).
= T), the aerodynamic force rises from the non-operating reference value S. Thereafter, when the air volume is made constant, the aerodynamic force becomes a constant magnitude and does not change. Since the displacement amount supports the measured vehicle 11 fixedly, the reference value S
Does not change from.

[0006] However, during actual running, although the phenomenon that the aerodynamic force changes every time the vehicle attitude changes as described above, the vehicle 1 to be measured may not work.
Since 1 is fixedly supported by the tire support rod 30, the suspension line 32, and the like, its movement is confined, the measured vehicle 11 is not displaced, and the aerodynamic force does not change from a certain level. Therefore, there is a problem that the above-mentioned phenomenon cannot be discovered by the conventional wind tunnel experiment apparatus, and the aerodynamic force, the displacement amount, and the like of the measured vehicle 11 cannot be evaluated in a form close to the actual running state.

Accordingly, the present invention is to allow a measured vehicle to be freely movable so that the amount of displacement in the vertical direction or the like acting on the measured vehicle can be measured in a form close to the actual running state. With the goal.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a wind tunnel test apparatus according to the present invention is designed so that a tire of a vehicle to be measured comes into contact with the tire.
The floor surface is movable , and the tire rotates with the floor surface.
Causes the rotation, in the pre-Symbol wind tunnel testing apparatus for measuring the air properties by the action of the wind to be measured vehicle, measuring said object end
Connected to a fixed vehicle, and the displacement of this measured vehicle
A support member having elasticity to expand and contract, and the other end of the support member
And expands and contracts due to the displacement of the measured vehicle.
The measured vehicle receives the amount of tension of the support member
A load measuring device for converting the aerodynamic force into
A displacement measuring device for measuring a displacement amount of the measuring vehicle .

[0009]

According to the wind tunnel test apparatus of the present invention, the floor on which the vehicle to be measured is installed is movable, and the tire of the vehicle to be measured is rotated. And when the wind acts from the front of the vehicle to be measured,
A positive pressure portion and a negative pressure portion are formed on the surface of the vehicle to be measured, and a pressure difference is generated, so that aerodynamic force is generated in the vehicle to be measured. Time of its, the
The support member expands and contracts due to the displacement of the measuring vehicle,
The amount of tension to be used depends on the aerodynamic force
Is converted to Also, the aerodynamic force acts on the measured vehicle
And the vehicle to be measured moves up and down
Or displaced horizontally. This displacement is measured by the displacement measuring instrument.
Measured .

[0010]

1 to 4 show an embodiment of the present invention.
It will be described based on. The size of the wind tunnel experimental device and the vehicle under measurement 11 (hereinafter referred to as vehicle 11) in the present embodiment,
The type (model, actual vehicle) and the like are not particularly limited.

FIG. 3 shows an overall view of the wind tunnel experimental apparatus of this embodiment. The wind tunnel experimental device is roughly divided into a wind generator 40 having a blower, a circuit 41 which is a wind path, and a vehicle 11.
It comprises a measuring unit 10 for measuring the aerodynamic force or the like.
The wind is generated by the wind generation unit 40, passes through the circulation channel 41, and acts on the vehicle 11 installed in the measurement unit 10 from the air outlet 19. Then, it is sucked through the suction port 20.

Next, the structure of the measuring section 10 of the wind tunnel experimental apparatus will be described with reference to FIG. FIG. 1 is a side view of the measuring unit 10. In the measuring section 10, the floor on which the vehicle 11 is installed is formed by a moving belt 12 having an endless track shape. The moving belt 12 includes an actuator 18
Rotates in the direction of arrow G, so that it rotates in the direction of arrow F (so that the vehicle 11 simulates in the traveling direction).

When the moving belt 12 is rotated, the tires 27 of the vehicle 11 are rotated, thereby creating a state in which the vehicle 11 is running in a simulated manner. Further, in this state, the vehicle 1
When the wind acts on 1 in the direction of arrow 13, the flow of the wind on the surface of the vehicle 11 and under the floor of the vehicle can be reproduced in a form close to the actual running state. In order to prevent the vehicle 11 from moving toward the suction port 20 due to the rotation of the moving belt 12, a cable 25 is connected between a part 26 of the fixed floor surface 24 of the measurement unit 10 and the vehicle 11. .

A load measuring device 14 and a displacement measuring device 15 as aerodynamic measuring devices are installed on a ceiling 21 of the measuring section 10 of the wind tunnel experimental device. The load measuring device 14 and the vehicle 11
They are connected via a spring 16 as a support member and a suspension line 17. The suspension line 17 has one end fixed to the roof 11 a of the vehicle 11, the other end connected to a spring 16, and the spring 16 connected to a load measuring device 14. In addition, the suspension line 17 accurately measures the load of the vehicle with the load measuring device 14.
, Is always stretched between the vehicle 11 and the load measuring device 14 by expansion and contraction of a spring 16. Also, spring 1
6 is connected to the suspension line 17 in a state where the suspension line 17 is stretched to some extent from the normal state (extension when no force is applied to the spring 16) when the suspension line 17 is stretched on the vehicle 11.

The displacement measuring device 15 is installed on the ceiling 21 of the measuring section 10 which is a fixed reference plane, and uses a laser beam to measure the amount of vertical displacement of the vehicle 11. The laser beam is emitted from the laser irradiation port 15a.
It is installed in the vehicle 11 and reciprocates on an optical path to a reflector (not shown). The values of the aerodynamic force and the displacement amount of the vehicle 11 are based on the values when the vehicle 11 is stopped (when the wind tunnel experimental device is not operating). In the present embodiment, the point S in the characteristic diagram of FIG. It is a reference value.

Next, a method for measuring the aerodynamic force of the vehicle 11 and the amount of displacement of the vehicle 11 in the vertical direction by the measuring unit 10 of the wind tunnel experimental apparatus according to the present embodiment will be described with reference to FIGS. As shown in FIG. 1, the vehicle 11 is set on the moving belt 12 of the measuring unit 10,
At 5, it is movably supported. Then, when the wind tunnel experimental device is not operating, the reference values of the displacement measuring device 15 and the load measuring device 14 are set. Thereafter, using this as a reference value, the time change of the aerodynamic force and displacement amount when the wind 13 is applied is measured. The reference value may be reset each time the vehicle 11 is changed or each time the wind tunnel experimental device is operated.

After the setting of the reference value is completed, the wind tunnel experiment apparatus is operated, and the moving belt 12 is rotated.
One tire 27 is rotated. Then, a certain amount of wind is blown from the blow port 19 in the direction of the arrow 13 and acts from the front of the vehicle 11. At that time, on the body surface of the vehicle 11,
For example, as shown in FIG. 2, a positive pressure portion 28 and a negative pressure portion 29 which are higher than the reference pressure are formed, and a pressure difference is generated between the two, so that pneumatic force is generated in the vehicle 11. The aerodynamic force is composed of a lift 22 that pushes the body of the vehicle 11 upward and a reverse lift 23 that pushes the body downward, as shown in FIG. , Its size and direction change. Therefore, the body of the vehicle 11 is displaced in the up-down direction by the generation of the aerodynamic force.

As described above, when the vehicle 11 is vertically displaced by air force, the suspension line 17 connected to the roof 11a is pulled in accordance with the movement of the vehicle 11. Suspension line 1
7 is converted into the magnitude of the aerodynamic force received by the vehicle 11 by the load measuring device 14. Further, the displacement amount of the vehicle 11 is measured by detecting the change in the reciprocating distance of the optical path of the laser beam irradiated to the vehicle 11 by the displacement measuring device 15.

According to the above-described measuring method, the temporal changes in the aerodynamic force and the displacement amount of the vehicle 11 are measured as an example of the "aerodynamic force-time" characteristic and the "displacement amount-time" characteristic in FIG.
FIG. 4 shows that a wind is applied to a measured vehicle 11 having a certain body shape from no wind (t = 0) to a certain amount (t = T).
Thereafter, the characteristic is obtained by applying a certain amount of wind.
According to this, the measured vehicle 11 has a shape that generates a small vertical vibration because the aerodynamic force and the displacement amount are pulsating when a certain amount of wind is applied (after t = T). I understand.

In the present embodiment, the spring 16 and the suspension line 17 are used as the supporting members. However, the present invention is not limited to this. Alternatively, the load measuring device 14 and the vehicle 11 may be connected by an elastic line member. . The suspension line 17 was connected between the roof 11a of the vehicle 11 and the load measuring device 14 vertically above the roof 11a, and the vertical aerodynamic force and displacement of the vehicle 11 were measured. A suspension line 17 is stretched in a horizontal direction from the side surface, the front or the rear of the vehicle 11 to the wind tunnel test apparatus, and how much air force is generated in the horizontal direction of the vehicle 11 and how much displacement is measured is measured. Good, hanging line 17
There are no limitations on the connection position, direction, stretching method, number, etc.

As another example of the structure of the support member, a vehicle is shown in which the cable 25 extended in the horizontal direction in FIG. 1 is used as a support member composed of a suspension line and a spring, and a part 26 of the fixed floor surface 24 is used as a load measuring device. It is also possible to measure the front-back aerodynamic force of 11. However, the supporting members such as the suspension lines 17
The load measuring device and the displacement measuring device are not limited to the configuration of the embodiment, on the premise that the load measuring device does not affect the measurement.

[0022]

According to the wind tunnel test apparatus of the present invention, since the vehicle to be measured is supported by the wind tunnel test apparatus so as to be freely movable, the movement of the vehicle to be measured by aerodynamic force can be reproduced in a form close to the actual running state. It is possible to measure the aerodynamic force and the amount of displacement that change every moment in that state.

Further, it is possible to predict and improve a minute vertical vibration due to the wind of the vehicle to be measured at the design stage by using the measured result.

[Brief description of the drawings]

FIG. 1 is a side view of a measurement unit of a wind tunnel experimental device according to an embodiment of the present invention.

FIG. 2 is a pressure distribution diagram when wind is applied to a vehicle to be measured.

FIG. 3 is an overall view of a wind tunnel experimental apparatus according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing an example of an “air force-time” characteristic and a “displacement-time” characteristic in the wind tunnel experimental apparatus according to the embodiment of the present invention.

FIG. 5 is a schematic diagram of a measurement unit of a conventional wind tunnel experimental device.

FIG. 6 “Aerodynamic force-time” in a conventional wind tunnel experimental device
FIG. 9 is a characteristic diagram showing an example of a characteristic, “displacement amount-time” characteristic.

[Explanation of symbols]

 Reference Signs List 10 Measurement part of wind tunnel experiment device 11 Measurement vehicle 12 Moving belt 13 Wind direction 14 Load measurement device 15 Displacement measurement device 16 Spring ( Supporting member) 17 Suspension line (supporting member)

Claims (1)

(57) [Claims] 1. A floor surface with which a tire of a vehicle to be measured contacts is movable , and when the tire is rotated by the floor surface,
Both pre SL in wind tunnel testing apparatus for measuring the air properties by the action of the wind to be measured vehicle, one end of which is connected to the measured vehicle, and the measured wheel
An elastic support member that expands and contracts due to both displacements,
Connected to the other end of the support member, and
The amount of tension of the support member that expands and contracts with
Load cell that converts the amount of aerodynamic force received by the measuring vehicle
Measuring instrument and a displacement measuring instrument for measuring a displacement amount of the measured vehicle
Wind Tunnel Experiment apparatus characterized by comprising and.