JPH0311928Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is suitable for an antenna device that rotates a directional antenna, that is, an antenna with a transmitting or receiving beam at a high speed of several tens of revolutions per second or more. The present invention relates to an antenna device.

[Conventional technology]

A well-known device of this type is one that protects the antenna body from snow accumulation, wind pressure, etc. by storing a directional antenna such as a slotted array antenna naked inside a protective dome and rotating it. .

In addition, a directional antenna with a reflector that has a structure in which the external shape in the horizontal plane is surrounded by a circle and formed into a flat cylindrical shape to reduce the resistance moment due to wind pressure is disclosed in Japanese Utility Model Publication No. 31-12814, etc. Japanese Patent Application Laid-Open No. 51-99955 has a structure in which a directional antenna is embedded in a solid or powdered dielectric object formed in a cylindrical shape with the direction as the axis to increase the distribution constant between antenna elements. has been disclosed.

[The problem that the idea attempts to solve]

A directional antenna that rotates at high speed may be used, for example, as an antenna for a direction finder, and must be an antenna device that rotates at a high speed of several tens of revolutions per second or more.

In such a case, there is the issue of resistance to centrifugal force as well as wind pressure resistance.In terms of resistance to wind pressure, it is sufficient to use the above-mentioned protective dome, but in terms of resistance to centrifugal force, miniaturization alone by increasing the distribution constant using the dielectric material described above is not enough. The weight becomes too heavy, making it difficult to adjust the balance of centrifugal force, resulting in inconveniences such as the inability to adjust the unbalance not only during manufacturing but also due to aging at the site.

Therefore, there is a problem in that it is desired to provide a simple and inexpensive product that does not have these inconveniences.

[Means to solve the problem]

This invention is based on a dome-shaped antenna device in which a directional antenna is rotated at high speed within a dome formed by closing the bottom side of a protective dome that surrounds the periphery and the upper surface. A foam-covered antenna in which at least the front and rear portions of a directional antenna are buried and covered by a foam protector having a circumferential side and an outer shape parallel to the inner surface of a protective dome; and the foam-covered antenna. The above problem can be solved by providing a rotation structure for rotating the protective dome around the circumferential axis direction of the protective dome.

〔Example〕

Examples will be described below with reference to figures.

In Figures 1 and 2, a directional antenna 1
For example, it is a Yagi antenna or a log periodic antenna, which has a sharp receiving or transmitting beam for radio waves in the target frequency band.

Although Fig. 1 shows a Yagi antenna made of a vertical conductor, it is possible to add a horizontally arranged conductor to this antenna to form a good receiving or transmitting beam even for horizontally polarized radio waves. I can do it.

The rotating shaft 2 holds a directional antenna 1 , takes out the input/output voltage of this antenna to a lead wire 8 , and supplies power to a lead wire 10 via a rotary coupler 9 .

The rotating shaft bearing 3 holds the rotating shaft 2 in a sliding state, and a speed reducer 7 is attached near the lower end thereof.
Although the rotary coupler 9 is attached to the middle portion of the rotating shaft 2 in the example shown in FIG. 2, it can also be attached to the lowermost end of the rotating shaft 2.

The motor 4 is rotated by electric power supplied to a power supply line 5 of the motor, and rotates the rotating shaft 2 at a substantially constant speed via decelerators 6 and 7.

The speed reducers 6 and 7 are exemplified by ohmic gears and wheel gears in FIG. 2, but speed reducers using belts and pulleys may also be used.

As can be seen in FIG. 2, the rotary coupler 9 is
This rotary coupler consists of a coil that is fixed to the rotating shaft 2 and rotates together with the rotating shaft 2, and a fixed coil that is connected to a lead wire 10 for coupling to a wave transmitting or receiving device. Impedance matching between the antenna 1 and the lead wire 10 is performed.

The mounting plate 11 has a bearing 3, a motor 4, and a lead wire 1.
0 is fixed and the antenna 1 is strong enough to be rotated by a motor 4.

The protective dome 12 surrounds the periphery and upper surface of the directional antenna 1, and has a cross section in the horizontal plane.
As shown in FIG. 1, it has a circumferential shape, and the bottom side is closed with a mounting plate 11 to form a dome.

The protective dome 12 is a dome made of a material that has extremely low loss when radio waves pass through the dome and is resistant to the surrounding environment such as wind, rain, and snow.
The cross section of the horizontal plane is finished smoothly so that it is almost circular, and the lower part is attached to the mounting plate 11 with a set screw 1.
It is fixed at 3.

A suitable material for the protective dome 12 is, for example, glass-filled fiber. The foam protector 15 is made of a material such as styrene material, which has extremely low loss when radio waves pass through it, is lightweight, and can be filled into the gap between the antenna 1. The outer periphery of the foam protector 15 is parallel to the inner surface of the protective dome 12, and is finished as smooth as possible.
Adjustment is made so that the centrifugal force during rotation of the speed reducers 6 and 7 is balanced.

That is, when the antenna 1 is rotated at high speed, the resistance between the inner surface of the protective dome 12 and the outer periphery of the foam protector 15 is reduced as much as possible, and the centrifugal force at the time of high speed rotation is adjusted so as to be balanced. Finish it.

To fill the foam material, place antenna 1 in a separate jig.
Insert the foam, position it, and attach a cover to prevent the foam from escaping.

Note that in order to reduce the weight of the rotating part including the antenna 1 and to facilitate the work of the lead wire 8, a cavity 14 is formed inside the foam protector 15.
can be provided.

To summarize the above configuration, in a dome-shaped antenna device in which the directional antenna 1 is rotated at high speed within a dome formed by closing the bottom side of a protective dome 12 that surrounds the periphery and the upper surface, the protective dome 1
At least the front and rear portions of the directional antenna 1 are filled and covered by a foam protector 15 whose inner surface side in the horizontal plane of the directional antenna 1 has a circumferential shape and whose outer shape is parallel to the inner surface of the protective dome 12. The antenna is configured to include a covered antenna and a rotation structure for rotating the foam covered antenna about the circumferential axis of the protective dome 12 described above.

[Effect of idea]

As described above, the present invention provides the foam protector 15.
Since the rotational strength of the directional antenna 1 is reinforced with a lightweight structure, it is easier to balance the centrifugal force during high-speed rotation, and the outer surface of the foam protector 15 and the inner surface of the dome 12 are Since they are parallel, the gap between them is constant, and even during high-speed rotation, there is no possibility of turbulence occurring inside and disrupting the balance of centrifugal force, allowing for smooth high-speed rotation.

Therefore, even the foam protector 15 can sufficiently reinforce the directional antenna 1, and since the foam protector 15 is lightweight, the rotating mechanism for high-speed rotation can be constructed with a light structure. Therefore, it has the advantage that the entire device can be made lightweight and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional top view of the main parts of the present invention.
A cross section taken along the line A-A in FIG. 2 is shown. FIG. 2 is a side view of a longitudinal section of the main part of the present invention, and shows the section BB in FIG. 1. 1... Directional antenna, 2... Rotation axis, 3...
...Rotating shaft bearing, 4...Motor, 5...Motor feed line, 6...Decelerator, 7...Decelerator, 8...Antenna lead wire, 9...Rotary type coupler, 10
...Coupler lead wire, 11...Mounting plate, 12...
...Protective dome, 13... Protective dome set screw, 1
4... Cavity for weight loss, 15... Foam protector, A... Section line for top view, B... Section line for side view, 16... Protective cover.

Claims (1)

[Claims for Utility Model Registration] 1. In a dome-shaped antenna device (hereinafter referred to as the device) in which a directional antenna is rotated at high speed within a dome formed by closing the bottom side of a protective dome surrounding the periphery and the top surface, a. A foam material whose inner surface side in a cross section in a horizontal plane of the protective dome is circular, and at least the front and rear portions of the directional antenna are buried and covered by a foam protector having an outer shape parallel to the inner surface of the protective dome. An apparatus comprising: a covered antenna; and b. a rotation structure for rotating the foam covered antenna about the circumferential axis direction. 2. The device according to claim 1 of the registered utility model, in which the foam protector is made of styrene foam. 3. The device according to claim 1 of the Utility Model Registration Claim, in which the directional antenna is a Yagi antenna. 4. Utility model registration The device according to claim 1, wherein the directional antenna is a log periodic antenna.