JPS60188854A - Wind direction meter - Google Patents

Abstract

PURPOSE:To reduce a time constant of self-vibration, to increase a response speed even in case of a low wind speed, and also to make a titled meter light in weight by installing an arrow vane at a prescribed angle and in a position of the center of gravity of the arrow vane, to two arrow vane installing shafts orthogonal to a rotary cylinder, and bending the upper part and the lower part of the arrow vane by a prescribed angle to the outside. CONSTITUTION:On a rotary cylinder 5, two arrow vane installing shafts 7 orthogonal to said cylinder are provided so as to be opposed to each other on the same straight line, and to both its end parts, an arrow vane 9 is installed so that the front part of the arrow vane is turned to the inside of a wind direction meter at a prescribed angle alpha, respectively, in a position of its center of gravity. The upper part and the lower part of the arrow vane 9 are bent at a prescribed angle beta to the outside so that the width (a) of the vertical surface of the upstream side of an air current becomes smaller than the width (b) of the downstream side. Also, the installing angle alpha of the arrow vane is made large, and said meter is made ligth in weight by omitting a balance weight, therefore, a continuous time of self-vibration is shortened, and it responds exactly and quickly even at the time of a low wind velocity. Also, the center of wind pressure retreats from a position of the center of gravity, and the stability against the horizontal wind is improved.

Description

[Detailed Description of the Invention] This invention relates to a +i counter, and more specifically,
There is a design related to a two-blade wind vane, in which two fletching feathers are placed at opposite positions to the axis of rotation and symmetrically to the center line of the wind vane.

Traditionally, wind vanes have generally been made from a single arrow blade, which is easy to construct. However, a single-blade fly vane has a self-oscillation time constant (when the wind suddenly blows from a direction perpendicular to the wind vane, it is the time from when the wind vane starts moving until it stops vibrating. Wind speed 1011 /SeC, it is said to be 5 seconds or less.) is large, and when the wind speed is low, it increases considerably. On the other hand, the team 11i'jl with two arrow feathers '(, -Il,) was often used;'I
Is it possible to write the 11.4 constant of self-oscillation small? I installation C
A C1 balanced heavy plow is required, and the fletching (q) is required.
Since the angle (the angle between the center line of the wind direction G1 and the plume's vertical i/j 'l') was relatively small, it was able to fully utilize its advantages. MaJ: lj;If the first gear is low, there is a problem that the response speed is slow.

This invention improves the deficiency Ji,t of the conventional two-blade wind opening, has a small time constant <,'b at low JII speeds, has a fast response speed, and has a lightweight wind direction h1. It is meant to cover the offer.

Generally, in order to reduce the time constant of the wind direction, (1)
Decrease the period of self-oscillation. (2) Increase the attenuation rate. (3) It is effective to reduce the value of 1 moment 1.
I3 (I found that if the mounting angle of the fletching was increased, the period of self-oscillation became smaller and the damping rate became weaker.) The two fletchers were rotated 1.10 times in the wind direction. '
z+ ihl+ vs. iii ``C1's respective center of gravity position if'' j odor (, arrow feather removal i'' axis) (=J kerukotoshiko, 1ζ°j sex 7-ment is significantly reduced However, W; a small effect was achieved in improving the time constant and response speed at low wind speeds.

Furthermore, by bending the upper and lower parts of the vertical plane of the fletching outward, the airflow from the horizontal front can be prevented from dispersing upward.
] It was found that the horizontal force of the airflow can be used effectively. In addition, by making the width of the vertical plane left by this bending smaller on the upstream side of the airflow than on the downstream side,
The center of wind pressure moves to IJ after reaching the center of gravity, and -C also becomes more stable against crosswinds. This invention was made based on such knowledge.

That is, on a rotating cylinder in the wind direction i1, there are two blunder plates perpendicular to the rotating cylinder ('J axis is installed at the opposite position to H), and the blunder plates (= arrow feathers are set at both ends of the I axis at a predetermined angle). L", H-)
The gist of the construction is to take the center of gravity of the fletching and bend it at a predetermined angle in response to an external force.

Next, regarding the embodiments of this invention (, attached (J drawing IJ J,
That's the explanation. Fixed 1 is installed in the center of 1, on the rotation axis 3 or on the right of rotation 1], and this fin +Ivt '1llll
A rotary cylinder 5 is mounted on the upper part of ζ3. On the rotary cylinder 5, there are two wooden boards of equal length that overlap each other (the q-axis 7 is
On the same straight line, the rotary cylinder 5 is placed in a line 71 at an anti-λ·j position U'Y, and the arrow blades 9 are placed in one line at the center of gravity at both ends. At Jj, the front part of the arrow faces toward the inside of Bill direction h1 at a predetermined angle α, J, and sea urchin ('J
4) The upper and lower portions of the fletching 9 are outwardly at a predetermined angle β (45 degrees with respect to the vertical plane in this embodiment) on the upstream side of the airflow! It is bent in a shape J such that the width a of the straight plane is smaller than the width of the downstream side.

Next, the operation of this embodiment will be explained. In FIG. γ'ji' (no change in content)
How many phrases α, its horizontal and vertical lengths are each 11
, d, its surface area and weight are S and W, respectively, and its center of gravity is G2. Gr, the density of air is P, and the center of the wind pressure of the fletching coincides with the center of gravity. Now the speed V
When the wind blows at an angle θ smaller than the installation angle α of the arrow blades with respect to the center iH of the wind vane, the component forces of wind pressure perpendicular to each arrow blade PL, Pr and the axis of rotation O due to these
The torques around TJ and Tr are as follows, respectively.

p2 = psl"sin" (α+θ)・・・・・・
・・・・・・・・・・・・・・・・・・・・・(1) Pr
2psV2sin” (α−θ)・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(2)'14 ””
2628M "5 inctsin" (α+θ)...
−・・・・・・・・・・・・(3) Tr==%zSV'si
nαsin'(α−θ)・・・・・・・・・・・・・・・
・(4) If the counterclockwise torque is positive, the torque T acting on the wind vane is the difference between T1 and Tr: T == pHt Slj'sinαsin 2α5i
n2θ・・・・・・・・・−・・−・・・・(5)
Meida 1114:'f':! : (no change in content). When θ is small, T=-(2%tS'L/'sinα5in2α)θ・・
・・・・・・・・・・・・・−+6). That is, the torque for turning the fletching is proportional to θ. If the torque for unit angular displacement is K, then K""Ply 5fsinα
sin 2α・・・・・・・・・・・・・・・・・・
...(7).

Next, the moment of inertia around the rotation axis 00 of this wind vane is calculated, and the weight of the fletching shaft is ignored.Generally, wind vanes have a damping torque proportional to the square of the angular velocity, and a damping torque proportional to the fletching weight. Since Coulomb friction acts on the vibration, the vibration becomes a nonlinear damped vibration, making calculation of the damping rate and natural frequency complicated.

Therefore, in order to simplify the following explanation, the isolateral linear damped vibration will be explained assuming that the Coulomb friction is ignored and the damping torque is proportional to the angular velocity.

If the damping torque for a unit angular velocity is C, then C is proportional to the area of the arrow blade in the rotational direction and approximately the square of the length of the mounting shaft. :+l13, γ・2: (no iΣ change in content)C
=(472”5sinα ・・・・・・・・・・・・・・・
−・・・・・・・・・・・・・・・(9). C
1 is a constant of proportionality.

The torque for the above unit angular displacement is 1 moment of inertia l-
I, the vibration of this wind vane due to damping torque C for unit angular velocity is ■ θ + C θ + 1 (θ = 0...Medium, Yuyu...
・・・・・・・・・(IQ)θ: A e-”LCO5(
q to −ψ)・・・・・・・・・・・・・・・・・・
......Represented by C11+. Here A, ψ
are the constants described above, and express μ and wo using the values of I and C.

μ is the attenuation constant, and as is clear from equation (12), if the mounting angle α of the fletching blade is increased, the area S thereof is increased, and the weight i:W of the wind vane is decreased, both of them increase. That is, the vibration stops quickly. This invention 18 open F38GO-188854
(3) is in line with these conditions. tl)o is the natural angular frequency (rad/sec) without damping
Then, the natural angular frequency t7 of this wind direction 81. - (rad
/sea) becomes a big deal if you make wo awkward. That is, the period becomes smaller. (As is clear from Equation (13), JJo reduces the weight W of the wind vane, and the length of the arrow blade (=l
When the angle α is increased, the area is increased, and the length is shortened, that is, when the wind blows at an angle θ in the wind direction 51, the response speed at which the Jll direction J1 follows the wind direction is determined by the characteristic of the wind direction it. Since it is proportional to the vibration angular velocity, if ho is increased, the velocity becomes larger and the response speed increases. Furthermore, as is clear from equation (13) (because So is proportional to I!ill 3W F, the response speed of wind direction h1 at low wind speed becomes small, but in this invention, as mentioned above, the response speed of wind direction h1 is small) By reducing the angle α and reducing the weight, we were able to significantly reduce the response speed at low wind speeds compared to conventional wind vanes.

・, i6'1ll-4i's 21 cloudy, jshi (no change in content) According to wind tunnel experiments of the wind vane of this invention in which the installation angle α of the fletching blade was set to 30 degrees, at a speed of 10 m/Sec. The time constant is 3.5 sec and 1.5 m
The time constant at low wind speed of /sec was 7.5 sec. Wind vane wind speed I Q m/time constant t at SQC. From this, the following is an empirical formula for calculating the time constant kn at an arbitrary wind speed "Ll'n.

According to equation (14), subtracting the time constant at 1.5 m/sec from the time constant of 3.5 seconds of Om/sec of this wind vane results in tn: 13.2 sec.

This value is the average hour'iJl number of a conventional wind vane.

In comparison, the wind vane of the present invention has a time constant of 7.5 seconds as described above, and vibrations quickly stop even at low wind speeds.

In this wind vane, the upper and lower parts of the fletching blades are bent outward, so the airflow is rectified, and even in the case of vertical and oblique airflow, the horizontal force can be effectively used, and the performance in wind direction i1 is improved. improved. Furthermore, the width of the vertical plane part has been made smaller than the rear part (11), and the center of pressure is set back from the center of the vehicle, improving stability against crosswinds.

Figure 115 shows another embodiment of the present invention in which the wind direction h1 of the present invention is taken at the small center position of the medium wind direction h111.

As can be understood from the above explanation, this Buto Ming is a waiting bar]
There are C's which are equipped with the structure described in the claims, and C's which have the following superior effects.

(1) Know the duration of self-oscillation.

(2) Responds accurately and quickly even to low wind speeds 11,i.

(3) Since no equilibrium Φ weight is required, 1. 'frij.

As a result of the above, there are some systems that can accurately and quickly change the dispatch direction for a wide range of speeds.

[Brief explanation of the drawing]

1, 2, and 3 are a front view, a top view, and a side view, respectively, of an embodiment of the present invention. FIG. 4 is an explanatory diagram of the operation of an embodiment of the present invention, and FIG. 5 is a three-dimensional diagram showing another embodiment. (Explanation of the main symbols shown in the drawings) 3...Rotating shaft 5...Rotating tube 7...Fetching shaft (Fig. 4q) Fig. 5 Procedure (ii) To the orthographic proboscis) Showa era February 2, 1959 Manabu Yoshiga, Commissioner of the Patent Office3, Person making the amendment, Agent address: 5th floor, Toranomon Doll, 1-2% 3, Toranomon, Minato-ku, Tokyo 105 Date of shipment: Showa J7 2Z day of r month) 1, Ji'sei's village is also old [] month-ft'la I471L light==l j4 gentleman'
J tL light-'+@-7,, nFH' positive η Rob Kumayama Kano 1ll-1/71 Ne3-Ken 1 rod 1 anti,
Imo zhong and sheep 7Q 茫 71r folk name, - out 1 s. (Ikl! Kuma 1: Yudo fJ L, ) δ attachment/1 special' parallel n catalog (1) Shirei IJn, 71 rod■, sheep/q 2?
^7 Summer and cylindrical shape.

Claims (1)

[Claims] Two fletching grippers 117 perpendicular to the rotation 11) 5 are provided at opposite positions to H, and the fletching attachment shaft 7
At both ends of the fletching, the fletching 9 is taken at a predetermined angle α and at the center of gravity of the fletching.
It is characterized by bending the i and 1 parts at a predetermined angle β due to external force.