JPH0679028B2 - Wind speed measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flow velocity measuring device for measuring a flow velocity of a fluid,
For example, it is effective when used as a wind speed sensor that is attached to a vehicle antenna or roof to measure the wind speed.

[Conventional technology]

A conventional flow velocity measuring device is, for example, Japanese Patent Publication No. 54-16233.
As shown in Japanese Patent Publication No. JP-A-2004-242, etc., it is provided with four sensing chambers divided in orthogonal directions along the longitudinal axis, and a probe provided with a pressure sensing port that communicates each chamber with the outside,
There is one that measures the wind speed in a specific direction by the air pressure difference in the room.

[Problems to be solved by the invention]

However, the conventional one has a problem that it is difficult to measure the flow velocity in all directions, although it is possible to individually measure the wind velocity in a specific one direction determined by the arrangement of the sensing ports. Also, depending on the relationship between the position where the pressure sensing port is opened and the flow velocity direction, there is a problem that raindrops, dust, etc. may enter or adhere to the port with respect to wind in a specific direction, which may affect the flow velocity measurement value. Had.

It is an object of the present invention to provide a flow velocity measuring device that solves the above problems. That is, the present invention has an object to provide a flow velocity measuring device that is excellent in weather resistance, particularly raindrop resistance, and is small in size and capable of measuring flow velocity in all directions when provided outside a vehicle such as a vehicle. .

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has a flow path through which a gas to be measured flows, and a cylindrical shape provided so as to project into the flow path and having an open end at one end, and the open end To
A tubular member having an outer periphery facing downward and arranged in parallel to the flow of gas, a pressure detecting means for generating a pressure signal according to the pressure inside the tubular member generated by the fluid, and the pressure And a wind speed calculating means for calculating a flow velocity in the flow path from the pressure signal when receiving the pressure signal from the detecting means.

[Action]

According to the present invention, with the above configuration, when the fluid flows around the open end of the tubular member, a negative pressure is generated from the open end of the tubular member to the inside thereof. Since this negative pressure changes according to the flow velocity, this negative pressure can be detected by the pressure detecting means and the flow velocity can be calculated from this pressure signal.

〔The invention's effect〕

The present invention, a tubular member having an open end at one end, so as to project into the flow path, the open end is disposed downward, and so as to be parallel to the flow of the gas, Raindrops flying with the fluid are less likely to enter the tubular member. In the state where the fluid is flowing, since the tubular member projects into the flow path, the flow velocity of the fluid below the tubular member increases,
Since the inside of the tubular member is in a negative pressure state, even if raindrops or the like adhere to the inside of the pressure conduit, they will be opened by the negative pressure generated in the tubular member. It has the effect of being pulled out toward the end side. Further, according to the present invention, by providing the tubular member, a negative pressure corresponding to the flow velocity is generated and detected inside the tubular member, so that the structure is simple,
In addition, there is an excellent effect that the size can be reduced.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described using a wind velocity measuring device attached to the tip of an antenna rod.

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG.
FIG. 3 is a sectional view taken along the lines AA and BB in FIG. 1, and FIG. 4 is a partial sectional view of the wind speed sensor.

10 is an antenna rod, the lower end 10a of which is supported by a support case 11 which is fixed to a part of the vehicle body, and the rod 10
Is fastened with bolts 12 so that it can be laid sideways in the front-rear direction of the vehicle in an emergency. A case 13 for detecting and measuring the wind speed and the wind direction is fixed to the upper end 10b of the rod 10.

The overall outer shape of the case 13 has a cylindrical shape so that the wind speed value is not affected by the wind directions in all directions. This case
Reference numeral 13 has a three-stage structure including a lower case portion 13a fixed to the rod 10, an intermediate case portion 13b above the upper case portion 13c, and an upper case portion 13c.
Each case portion 13a, 13b, 13c, by a net-like member centered on a plurality of thin support columns 14 provided along the outer peripheral edge thereof,
The flow path plates 15 and 16, 17 and 18 are supported in parallel,
Two flow paths 20 and 21 are formed by the flow path plates 15 to 18. As shown in FIG. 2, a wind speed detecting cylinder 22 is vertically attached to the central portion of the upper flow path plate 18 of the flow path 20. The cylinder 22 is
It has a diameter of about 8 mm to 10 mm, is cut in a plane orthogonal to its central axis, and has an end face of an aperture end 22a that is parallel to the flow path plates 17 and 18. The hole end 22a is the flow path plate 18
There is a downward opening. This makes the wind a cylinder
At the same time as being guided so as to be parallel to the end face of the hole end 22a of the hole 22, raindrops and the like do not enter the cylinder 22. Further, a void 37 is provided in the upper portion of the cylinder 22, a pressure port 22b for leading the pressure inside the cylinder 22 to the outside is formed on the side of the void 37, and a pressure outlet tube 23 is provided in the pressure port 22b. ing. This void 37 is provided for the purpose of preventing raindrops, dust, dust, etc. from blocking the pressure port 22b, and for alleviating a rapid pressure fluctuation and extracting a stable negative pressure to the pressure port 22b. . The pressure in the cylinder 22 is
It is led to the semiconductor pressure detector 24 provided in the support case 11 via the pressure lead-out tube 23. Tube 23
The upper case portion 13c, the intermediate case portion 13b, the pipe 25 penetrating the upper case portion 13a, and the support case 11 are arranged through the inside of the antenna rod 10. The pipe 25 is a wind speed detection cylinder.
In order to reduce the influence on 22, it is provided on the downstream side with respect to the main wind direction to be detected, for example, in the case of a vehicle, on the rear side in the traveling direction.

Further, as shown in FIG. 3, wind direction measuring columns 30, 31, 32 are attached to the upper flow path plate 16 of the flow path 21. Each cylinder 30,3
1, 32 are pressure detection holes 30a, 31a, which are opened toward the downstream side.
32a is provided, and the pressure in the holes 30a, 31a, 32a is
It is guided to the semiconductor pressure detectors 33 and 34 through the ports and pressure derivation tubes formed in the upper portions of 30, 31 and 32. Column 3
Between 0 and 31 or between the cylinders 30 and 32, there is a phenomenon that a negative pressure corresponding to the wind direction is generated on the downstream side of the cylinder 30 at a constant wind speed, and this negative pressure causes the pressure detector 33 to detect the wind direction. it can. Further, the pressure detector 34 for the negative pressure generated on the downstream side of the cylinders 31, 32 provided at the symmetrical positions is used to determine which of the left and right directions the wind is coming from.

Next, the operation of measuring the wind speed based on the above configuration will be described.

FIG. 4 shows a partially enlarged sectional view of FIG.
Negative pressure is generated in the wind velocity detection cylinder 22 because it flows in the flow path 20 formed by 17, 18 substantially parallel to the plates 17, 18 and flows fastest near the open end 22 of the cylinder 22. . This negative pressure (PV) has the characteristic that it increases as the wind speed (U) increases, as shown in FIG. Therefore, the pressure generated in the cylinder 22 can be guided to the semiconductor pressure sensor 24 by the pressure port 22b and the pressure derivation tube 23 and measured, and the wind speed can be measured from this pressure signal.

Further, in a windy state, negative pressure is generated in the cylinder 22 and the opening end 22a is opened downward, so raindrops, dust, No dust will enter. Further, even if raindrops or the like adhere to the pressure port 22b when there is no wind, the pressure port 22b is pulled out by the negative pressure in the cylinder 22 generated by the blowing out of the wind.

FIG. 5 also shows the results of measuring the pressure in rain with raindrops. The rainfall at this time is 4.2 mm / min. As shown in FIG. 5, when comparing rainfall and non-rainfall, the negative pressure in the cylinder 22 has a slight difference, but it does not affect the actual measurement of the wind speed. Therefore, in the above-mentioned embodiment, raindrops and the like do not enter the pressure port 22b, and since it is possible to detect and measure a substantially accurate wind speed even during rainfall and non-rainfall, it is excellent in weather resistance, particularly raindrop resistance. It can be said that

Further, the pressure detection cylinder 22 has the end face of the open end 22a of the flow path plate 1
Since it is parallel to 7,18, the end surface of the open end 22a of the cylinder 22 is always parallel to the air flow, so this cylinder
The negative pressure in 22 does not depend on the wind direction but only on the wind speed. Therefore, it is possible to easily and accurately detect the wind speed in all directions without separately detecting each wind speed component of a specific wind direction and detecting the wind speed by combining the measured values as in the conventional case.

Next, FIG. 6 shows the measurement circuit of this embodiment. Pressure detector
A semiconductor pressure sensor is used for 22. The electronic control unit (ECU) 40 has an analog power supply 41 and a digital power supply 4
2, an amplifier / filter unit 43-1, an A / D converter 43-2, an amplifier / filter unit 43, a D / A converter 44, and a microcomputer 45. The power supplied from the power supply terminals 40-1, 40-2 of the electronic control unit 40 is
The analog power supply 41 supplies a constant voltage current to the semiconductor pressure sensor 24 through the output terminals 40-3 and 40-4. The analog power supply 41 also supplies a constant voltage current to the amplifier / filter unit 43 and the digital power supply 42. The digital power supply 42 supplies the operating power of the microcomputer. A negative pressure indicating the wind speed detected by the wind direction detection cylinder 22 is electrically converted by the semiconductor pressure sensor 24.
The output voltage of the semiconductor pressure sensor 24 is the electronic control unit 40
It is input to the amplifier / filter unit 43 through the input terminal 46 of. The signal amplified and digitized by the amplifier / filter unit 43 is output by the microcomputer 45 as a wind speed output from the output terminal 47 through the D / A converter 44 as a result.

Next, a method of calculating the wind speed in this embodiment will be described. First, the relationship between the wind speed and the output of the semiconductor pressure sensor 24 is obtained in advance by verification, and a one-dimensional map such as the seventh one is stored in the memory. FIG. 8 is a calculation flowchart of wind speed measurement. The calculation is started from step 50. Step 51
Then, the output is read by the semiconductor pressure sensor 24 based on the negative pressure in the wind speed detection cylinder 22. Step 52, Step
The wind speed is calculated by tracing the map as shown in FIG. 7 based on the data read in 51. In addition, since the map created by the verification has the map points dispersed, interpolation is performed between the map points. In step 53, the calculated wind speed is output, and the process returns to step 51 to perform the next measurement.

Although the semiconductor pressure sensor is used to measure the negative pressure in the cylinder due to the wind speed in the above embodiment, any other sensor may be used as long as it can detect the gas pressure.

Further, in the above-described embodiment, the pressure in the wind speed detection cylinder 22 is guided to the semiconductor pressure sensor 24 in the support case 11 via the antenna rod 10 by the pressure derivation tube 23, but the semiconductor pressure sensor 24 is used as the upper case. The pressure signal from this sensor may be derived via a lead wire as a structure to be housed in the portion 13c.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which the flow velocity measuring device of the present invention is applied to a wind speed sensor provided on an antenna rod, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. First
4 is a sectional view taken along the line BB in FIG. 4, FIG. 4 is an enlarged sectional view of an essential part of the wind speed sensor shown in FIG. 1, and FIG. 5 is wind speed (U).
And FIG. 6 is an experimental characteristic diagram showing the relationship between negative pressure in the wind speed detection cylinder (22), FIG. 6 is a configuration diagram showing a measurement circuit, and FIG. 7 is a map stored in a memory in the microcomputer (45).
FIG. 8 is a map characteristic diagram showing the relationship between the measured pressure and the calculated wind speed, and FIG. 8 is a flow chart showing the calculation in the microcomputer (45). 17, 18 ...... Flow plate, 22 ...... Wind speed detection cylinder, 22a ...... Open end of wind speed detection cylinder, 22b ...... Pressure port, 23 ...... Pressure derivation tube, 24 ...... Semiconductor pressure sensor.

Claims (2)

[Claims] 1. A flow path through which a gas to be measured flows, and a cylindrical shape which is provided so as to project into the flow path and has an open end at one end, and the open end has an outer periphery facing downward,
And a tubular member arranged in parallel to the flow of the gas, a pressure detection unit for generating a pressure signal according to the pressure inside the tubular member generated by the gas, and from the pressure detection unit A wind velocity measuring device comprising: a flow velocity calculating means for receiving a pressure signal and calculating a flow velocity in the flow path from the pressure signal. 2. The tubular member is such that, of the two parallel flow path plates forming the flow path, the outer periphery of the opening end is parallel to the upper flow path plate and is parallel to the flow path. The wind velocity measuring device according to claim 1, wherein the wind velocity measuring device is provided so as to project.