JP2005009973A - Anemometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the measurement accuracy in an anemometer using an optical revolution detector. <P>SOLUTION: In the anemometer, wind speed is measured by noncontactly detecting the revolutions of a propeller with the optical revolution detector. The optical revolution detector is provided with a disk connected to the propeller and having groove parts formed on a peripheral face at predetermined intervals, a light irradiation receiving means applying detecting light with the detecting light condensed to one side of the peripheral face or the groove parts through an objective lens and receiving reflected light obtained from the disk through the objective lens, and an output means outputting light receiving output of the light irradiation receiving means to the outside as a wind speed signal showing the wind speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anemometer using an optical rotation detector.
[0002]
[Prior art]
Some anemometers measure the wind speed by detecting the rotation of the prober in a non-contact manner using a rotation detector using light (optical rotation detector). This optical rotation detector emits light from an optical fiber toward a slit plate connected to a prober, and receives the reflected light to generate a pulse signal based on the intensity of the reflected light. An anemometer using such an optical rotation detector measures the wind speed by counting the pulse signals. Such optical rotation detectors are disclosed in, for example, Japanese Utility Model Publication No. 63-10527, Japanese Utility Model Publication No. 63-11657, Japanese Patent Application Laid-Open No. 8-160063, and the like.
[0003]
[Patent Document 1]
Japanese Utility Model Publication No. 63-10527 [Patent Document 2]
Japanese Utility Model Publication No. 63-11657 [Patent Document 3]
JP-A-8-160063 [0004]
[Problems to be solved by the invention]
By the way, in the above prior art, since the reflected light is obtained by irradiating the slit plate with the emitted light of the optical fiber having a relatively large spot diameter, the number of slits of the slit plate is limited and high-precision rotation detection cannot be performed. That is, when the spot diameter of light is large, it is necessary to use a slit plate in which slits are formed at a wide interval. Therefore, the number of slits is inevitably reduced, and the reflected light obtained by rotating the slit plate once. The number of pulses decreases. The fact that the number of pulses is small means that the rotation detection accuracy is low, and therefore the wind speed measurement accuracy is low.
[0005]
Further, in the conventional optical rotation detector, the optical system is composed of a plurality of individual parts such as light emitting elements such as LEDs, light receiving elements such as optical fibers and photodiodes, etc. There is also a problem that the cost is high.
[0006]
The object of the present invention is to improve the measurement accuracy of the wind speed and reduce the manufacturing cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, in an anemometer that measures the wind speed by non-contact detection of the rotation of the propeller by the optical rotation detector, the optical rotation detector is connected to the propeller and is mounted on the circumferential surface. A circular body having grooves formed at predetermined intervals and the objective lens are used to irradiate the detection light in a condensed state on either the peripheral surface or the groove part, and the reflected light obtained from the circular body is reflected on the objective lens. The light irradiation light receiving means that receives light via the light, and the output means that outputs the light reception output of the light irradiation light receiving means as a wind speed signal indicating the wind speed to the outside are employed.
[0008]
That is, according to such means, since the detection light is irradiated in a state of being condensed on either the circumferential surface or the groove of the circular body, the reflected light obtained from the portion where the detection light is condensed has an intensity. The intensity of the reflected light which is strong and is obtained from a portion where the detection light is not condensed is weak. For example, when the detection light is collected on the peripheral surface, the intensity of the reflected light from the peripheral surface is increased, and the intensity of the reflected light from the groove portion is reduced compared to this. On the other hand, when the detection light is condensed on the groove, the intensity of the reflected light from the groove is increased, and the intensity of the reflected light from the peripheral surface is lower than this. Since the detection light is alternately irradiated onto the peripheral surface and the groove as the circular body rotates, the intensity of the reflected light repeatedly increases and decreases.
[0009]
Further, since the detection light is condensed and irradiated on the peripheral surface or the groove portion, the light spot on the peripheral surface or the groove portion is extremely small. The spot diameter of this light spot depends on the performance of the objective lens and the nature of the detection light, but is a diameter that is significantly smaller than at least the light emitted from the end face of the optical fiber as in the prior art.
[0010]
In the present invention, in the above-mentioned means, means for arranging an external light shielding means for shielding external light between the circular body and the light irradiation / light receiving means is adopted. By adopting such means, it is possible to prevent external light from acting as a disturbance.
[0011]
Further, in the present invention, in each of the above means, the light irradiation / light receiving means is arranged on the base material adjacent to the LED, the base material having a flat surface, the objective lens, the LED arranged on the base material, and the LED. In this case, a unit is used which is formed as a single part including a photodiode and a lens holder which is fixed to a substrate and which has an LED and an objective lens fixedly disposed in front of the photodiode. Thus, the various parts which comprise an optical system are comprised as a single part, and the assembly in manufacture becomes easy.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a case where the present invention is applied to an anemometer having a wind direction measuring function in addition to a wind speed measuring function.
[0013]
FIG. 1 is a front view showing an appearance and a partial cross section of the anemometer, and FIG. As shown in this figure, in the anemometer, a propeller 3 is rotatably attached to a front end portion of a substantially hollow cylindrical body 1 via a propeller shaft 2 and a wing 4 is attached to a rear end portion of the body 1. And the center of the body 1 is attached to a hollow fixed stand 6 so as to be rotatable in a direction perpendicular to the propeller shaft 2 through the wind direction shaft 5.
[0014]
In the body 1, a disc-shaped encoder 7 (circular body) is attached to the rear end portion of the propeller shaft 2. The encoder 7 is a disk having a constant thickness as shown in the figure, and grooves 7b are formed on the peripheral surface 7a at regular intervals (see FIG. 2). That is, since the peripheral surface 7a of the encoder 7 is formed so that the groove portions 7b are spaced at regular intervals, the convex and concave portions in which the convex portions formed by the peripheral surface 7a and the concave portions formed by the groove portions 7b are regularly arranged. It has become.
[0015]
On the other hand, the wind direction shaft 5 is in a double cylinder state, and a fixed shaft 8 having a lower end fixed to the body 1 is provided therein. And the sensor part 9 is being fixed to the upper end of this fixed shaft 8 in the state which opposes the surrounding surface 7a of the said encoder 7. FIG. As shown in FIG. 2, the sensor unit 9 is fixed to a substantially cylindrical optical sensor 10 (light irradiation / receiving means) and the optical sensor 10 in a state of being separated from the encoder 7 by a certain distance D. The three holder members 11 to 13 are configured. The optical sensor 10 and the encoder 7 constitute an optical rotation detector in the present embodiment.
[0016]
Among these holder members 11 to 13, the holder member 11 is a substantially hollow cylindrical resin member having both end faces open, and is fitted and fixed in the substantially hollow cylindrical holder member 12. The optical sensor 10 is fixed in a state in which the position of the optical sensor 10 is restricted in the holder member 12 by being press-fitted into the holder member 11 so that the inner peripheral surface of the optical sensor 10 is pressed against the inner peripheral surface of the holder member 11. The holder member 12 is a metal member, and a window portion 14 (external light shielding means) is formed at the upper end.
[0017]
The window portion 14 is for passing the detection light emitted from the optical sensor 10 and its reflected light and shielding outside light, and has a trapezoidal cross section as shown. The optical sensor 10 faces the peripheral surface 7a and the groove 7b of the encoder 7 with the window 14 interposed therebetween. The holder member 12 having such a window portion 14 is inserted into the holder member 13 from the upper opening side of the holder member 13 formed in a substantially hollow cylindrical shape and fixed with screws.
[0018]
The insertion amount of the holder member 12 into the holder member 13 is adjusted so that the optical sensor 10 and the peripheral surface 7a of the encoder 7 have a constant distance D. Thus, the holder member 13 in which the optical sensor 10 is fixed inside through the holder members 11 and 12 has a lower end fixed to the upper end of the fixed shaft 8.
[0019]
In the fixed stand 6, a wind direction detection unit 15, a circuit board 16 and the like are provided. The wind direction detection unit 15 detects the wind direction based on the rotation state of the wind direction shaft 5. On the other hand, the circuit board 16 outputs the detection signal of the wind direction detection unit 15 to the outside as a measurement signal indicating the wind direction, and outputs the detection signal of the optical sensor 10 to the outside as a measurement signal indicating the wind speed. Is to do.
[0020]
Next, a detailed configuration of the optical sensor 10 will be described with reference to FIG.
In this optical sensor 10, an LED 10b and a phototransistor 10c are disposed adjacent to each other on the surface of a circular plate-shaped substrate 10a, and an objective lens 10d is fixedly disposed in front of the LED 10b and the phototransistor 10c.
[0021]
As shown in the figure, the objective lens 10d condenses the detection light so that the focus of the detection light emitted from the LED 10b is connected to the peripheral surface 7a of the encoder 7, and the detection light is reflected by the peripheral surface 7a or the groove 7b. The reflected light that is returned is condensed on the light receiving surface of the phototransistor 10c. That is, the objective lens 10 d is optically designed so that the focal length is the position of the peripheral surface 7 a of the encoder 7. Such an objective lens 10d is housed in a case 10f together with the LED 10b and the phototransistor 10c.
[0022]
The case 10f is formed in a substantially hollow cylindrical shape in which the base material 10a is fitted to one end and the circular glass plate 10e is fitted to the other end, and the objective lens 10d is fixed in front of the LED 10b and the phototransistor 10c. It is also a lens holder. Further, a terminal 10g for electrically connecting the LED 10b and the phototransistor 10cLED 10b to the outside is provided on the back surface of the base material 10a. Thus, the optical sensor 10 is formed as a single optical component.
[0023]
Next, the operation of the anemometer constructed as described above will be described in detail.
In such an anemometer, when the wing 4 receives wind, the fuselage 1 (that is, the wind direction shaft 5) rotates and the posture is set in a direction corresponding to the wind direction. The rotation of the wind direction shaft 5 is detected by the wind direction detection unit 15 and converted into a detection signal, and further converted into a measurement signal indicating the wind direction by the circuit board 16 and output to the outside.
[0024]
In parallel with the wind direction measurement, the encoder 7 rotates when the propeller 3 receives the wind. The rotation of the encoder 7 is converted into a detection signal by the optical sensor 10 and further converted into a measurement signal indicating the wind speed by the circuit board 16 and output to the outside.
[0025]
Since the distance D between the optical sensor 10 and the encoder 7 is accurately regulated in accordance with the focal length of the objective lens 10d, the detection light emitted from the LED 10b is rotated around the encoder 7 rotated by wind. The surface 7a is always irradiated to the peripheral surface 7a or the groove 7b in a state where the surface 7a is accurately focused. As a result, of the reflected light obtained by irradiating the detection light to the peripheral surface 7a or the groove 7b, the reflected light of the peripheral surface 7a that is a condensing surface is strong and the reflected light of the groove 7b that is a non-condensing surface. Is weaker than the reflected light of the peripheral surface 7a.
[0026]
Such reflected light from the peripheral surface 7a and reflected light from the groove 7b are alternately generated as the encoder 7 rotates. The intensity repetition frequency of the reflected light corresponds to the rotational speed of the encoder 7 (propeller 3), that is, the wind speed. The phototransistor 10c receives such reflected light, and its detection signal is a signal whose voltage level changes in response to the intensity of the reflected light, and the repetition frequency of the voltage level corresponds to the wind speed. It will be a thing. The circuit board 15 converts such a detection signal into, for example, a pulse signal and outputs it as a measurement signal to the outside.
[0027]
Here, in the present anemometer, the detection light emitted from the LED 10b is applied to the encoder 7 so as to focus on the peripheral surface 7a as described above, and therefore the diameter (spot diameter) of the light spot is at least. As in the prior art, the spot diameter of light emitted from the end face of the optical fiber is significantly smaller. The interval between the groove portions 7b (that is, the peripheral surface 7a) in the encoder 7 is set to a short interval corresponding to this small spot diameter.
[0028]
That is, according to the present anemometer, the number of the pulse signals obtained when the encoder 7 makes one rotation is larger than the conventional one, and therefore the rotational speed of the encoder 7, that is, the wind speed can be measured with high accuracy. In the prior art, the wind speed measurement accuracy was constrained by the relatively large spot diameter of the detection light emitted from the optical fiber, but in this anemometer, the spot diameter of the detection light is substantially the wind speed measurement accuracy. Is not constrained.
[0029]
In addition, according to the anemometer, since the window portion 14 that shields the external light and passes only the detection light emitted from the sensor 10 and the reflected light from the encoder 7 is provided, the external light is converted into the reflected light. It is possible to prevent the light from being mixed and received by the phototransistor 10c, and therefore it is possible to prevent a decrease in wind speed measurement accuracy due to external light.
[0030]
Furthermore, the optical sensor 10 of the anemometer is easy to make optical adjustments because the optical parts such as the LED 10b, the phototransistor 10c, and the objective lens 10d are formed as an integral part through the base 10a and the case 10f. It is. That is, the optical adjustment point is only the distance D between the peripheral surface 7a of the encoder 7 and the optical sensor 10, and this distance D is easily adjusted by the configuration of the sensor unit 9 described above. Therefore, the anemometer is easy to adjust the optical system in manufacturing, so that it can be easily assembled and the manufacturing cost can be reduced.
[0031]
In the above-described embodiment, the peripheral surface 7a of the encoder 7 is set as the condensing surface of the detection light, but the present invention is not limited to this. Instead of the peripheral surface 7a, the groove portion 7b may be set as a condensing surface.
Moreover, although the said embodiment is related with the case where this invention is applied to an anemometer, this invention is not limited to this. ,
[0032]
【The invention's effect】
As described above, according to the present invention, in the anemometer that measures the wind speed by non-contact detection of the rotation of the propeller by the optical rotation detector, the optical rotation detector is connected to the propeller and is provided on the circumferential surface. A circular body having grooves formed at predetermined intervals and the objective lens are used to irradiate the detection light in a focused state on either the peripheral surface or the groove part, and the reflected light obtained from the circular body is irradiated to the objective lens. Therefore, it is possible to improve the measurement accuracy of the wind speed. The light irradiation / light receiving means for receiving the light and the output means for outputting the light reception output of the light irradiation / light receiving means to the outside as a wind speed signal indicating the wind speed are provided.
[Brief description of the drawings]
FIG. 1 is a front view showing an appearance and a partial cross section of an anemometer according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of an anemometer according to an embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of an optical sensor in an anemometer according to an embodiment of the present invention.
[Explanation of symbols]
1 ... Body 2 ... Propeller shaft 3 ... Propeller 4 ... Wings 5 ... Wind direction shaft 6 ... Fixed stand 7 ... Encoder (circle)
7a ... peripheral surface 7b ... groove 8 ... fixed shaft 9 ... sensor 10 ... optical sensor (light irradiation light receiving means)
10a: Base material 10b: LED
10c ... Phototransistor 10d ... Objective lens 10e ... Glass plate 10f ... Cases 11-13 ... Holder member 14 ... Window (outside light shielding means)
15 …… Wind direction detector 16 …… Circuit board

Claims (3)

An anemometer that measures the wind speed by non-contact detection of the rotation of the propeller with a light rotation detector,
The optical rotation detector is
A circular body connected to the propeller and having grooves formed at predetermined intervals on the peripheral surface;
A light irradiating light receiving means for irradiating the detection light through the objective lens in a state of being condensed on either the peripheral surface or the groove and receiving the reflected light obtained from the circular body through the objective lens; ,
An anemometer comprising: output means for outputting the light reception output of the light irradiation light receiving means to the outside as a wind speed signal indicating the wind speed. The anemometer according to claim 1, further comprising external light shielding means for shielding external light between the circular body and the light irradiation light receiving means. The light irradiation light receiving means is
A substrate having a plane;
An objective lens;
LEDs disposed on the substrate;
A photodiode disposed on a substrate adjacent to the LED;
The anemometer according to claim 1 or 2, wherein the anemometer is a single part comprising a lens holder fixed to the substrate and having an objective lens fixedly disposed in front of an LED and a photodiode.

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