JPH0611614Y2 - Sub-reflector support device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sub-reflector supporting device for an antenna (for example, an Asegren antenna) having a sub-reflector and having a variable depression angle.

(Prior Art) Conventionally, as a method for attaching a sub-reflecting mirror of an antenna with a variable depression / elevation angle to a support column, fixing with screws or the like has been common.

(Problems to be solved by the invention) In the case of the above-mentioned method, since the support column supporting the sub-reflector is elastically deformed by the weight of the sub-reflector or the weight of the support column itself, When the action direction changes, the amount of elastic deformation of the support column also changes, and the position of the sub-reflecting mirror fixed to the support column also moves. The lateral movement of the subreflector with respect to the antenna radiation axis significantly impairs the side lobe level symmetry of the antenna radiation pattern.

(Means for Solving Problems) A sub-reflector supporting device provided by the present invention in order to solve the above-mentioned problems includes a support column fixed to a main reflector and radio waves emitted from a radiator. A sub-reflecting mirror that reflects toward the main reflecting mirror, a large bevel gear that is rotatably supported about a horizontal axis fixed to the main reflecting mirror, and a small bevel gear that meshes with the large bevel gear. A shaft supporting member for rotatably supporting the shaft of the large bevel gear, and a base cam provided on the support column, the disc-shaped cam moving the shaft of the sub-reflecting mirror according to the rotation of the small bevel gear. Is provided on the base, a weight is provided on the large cam gear at a position offset with respect to the shaft of the large cam gear, the disc-shaped cam has a spiral guide groove, and the guide pin has the auxiliary pin. Standing on the back of the reflector, The guide pin is loosely inserted in the guide groove and slides along the guide groove in response to the rotation of the disc-shaped cam. When the guide pin slides along the guide groove, A guide hole for sliding the sub-reflecting mirror according to the movement is provided in the base, and the shaft of the small bevel gear is erected coaxially with the rotation center of the disc-shaped cam.

(Example) Next, this invention is demonstrated with reference to drawings.

FIG. 1 is a partially broken cross-sectional view showing a sub-reflecting mirror supporting device according to an embodiment of the present invention, and FIG. 2 is a plan view showing a disc-shaped cam of the sub-reflecting mirror supporting device of FIG.

In the figure, 1 is a support pillar, 2 is a base, 3 is a sub-reflector, 4 is a guide hole, 5 is a slider part, 6 is a guide pin, 7 is a disk-shaped cam, 8 is a guide groove, 9 is a small bevel gear, 10 is a large bevel gear, 11 is a weight, 12 is a shaft support member, 13 and 16 are shafts, 14 is an arm, 1
5 is a pin.

The support column 1 is fixed to the main reflecting mirror. The shaft support member 12 is fixed to the support column 1. The shaft 13 is rotatably inserted in the shaft support member 12. The arm 14 and the large bevel gear 10 are coaxially connected to the shaft 13. The pin 15 fixes the large bevel gear 10 and the arm 14. The weight 11 is fixed to the end of the arm 14. The small bevel gear 9 and the disc cam 7 are coaxially fixed by a shaft 16.

A slider section 5 is provided at the center of the back surface of the sub-reflecting mirror 3. A guide pin 6 is erected on the slider portion 5, and the guide pin 6 is loosely inserted in a disc-shaped cam 7. As shown in FIG. 2, the disc-shaped cam 7 is provided with a spiral guide groove 8. The guide groove 8 slides and guides the guide pin 6 according to the rotation of the disc-shaped cam 7. When the main reflecting mirror performs the elevation motion, the support column 1 fixed to the main reflecting mirror rotates in the same direction as the main reflecting mirror (for example, the direction of arrow 20 in FIG. 1). A plate-shaped base 2 integral with the support column 1, a sub-reflecting mirror 3 slidably mounted in a guide hole 4 of the base 2 by a slider portion 5, and a base 2 perpendicular to the plate surface of the base 2. Shaft 16 and Shaft 1 mounted for rotation
The small bevel gear 9 fixed to one end of 6, the large bevel gear 10 meshed with the small bevel gear 9, and the weight 11 fixed to the large bevel gear 10 by the pin 15 rotate together with the main reflecting mirror. To do. Due to this rotation, the weight 11 is displaced from directly below the shaft 13, so that the weight 11 causes the weight 11 to move toward the shaft 13.
The large bevel gear 10 is rotated by the weight 11 until it goes right below.

The guide hole 4 is a rectangular hole that is long in the lateral direction in FIG. 1, and is provided so as to penetrate the base 2. An upper end and a lower end of the slider portion 5 fixed to the back surface of the sub-reflecting mirror 3 have a brim shape wider than the central portion thereof, and the central portion is loosely inserted in the guide hole 4. The guide pin 6 is erected on the upper end of the brim.

On the back surface of the sub-reflecting mirror 3, a guide pin 6 that is loosely inserted in the guide groove 4 of the disc-shaped cam 7 is provided upright.

As shown in FIG. 2, the disc-shaped cam 7 is provided with a spiral guide groove 8. The guide groove 8 smoothly guides the loosely inserted guide pin 6 according to the rotation of the disc-shaped cam 7. The board-shaped cam 7 rotates according to the elevation movement of the main reflecting mirror, and the guide pin 6 is guided in the guide groove 8 of the board-shaped cam 7.

In the sub-reflector supporting device having the above structure, when the Cassegrain type antenna rotates in elevation, the weight 11 causes the large bevel gear 10 to relatively rotate, which causes the disc-shaped cam 7 to rotate. Then, the sub-reflecting mirror 3 moves along the base 2 along its guide groove 8. For example, suppose that the antenna rotates by θ in the direction of arrow 20. At this time, the large bevel gear 10 is rotated by θ in the direction of the arrow 21 with respect to the support column 1 by the action of the weight 11. Then, the small bevel gear 9 rotates and the disc-shaped cam 7 also rotates, so that the guide pin 6 slides along the guide groove 8 and the slider portion 5 is provided at the center of the rear surface of the sub-reflecting mirror 3, and the slider thereof is provided. Since the guide pin 6 is fixed and erected on the portion 5, the guide pin 6 slides along the guide groove 8, and the movement of the guide pin 6 causes the sub-reflecting mirror 3 to interlock.

When the antenna, that is, the main reflecting mirror rotates in the elevation direction, the weight 11 rotates by an angle corresponding to the angular displacement of the rotation on a one-to-one basis. The support column 1 is elastically deformed according to the elevation angle of the main reflecting mirror. Due to this elastic deformation, the mirror axis of the sub-reflecting mirror 3 deviates from the mirror axis of the main reflecting mirror. Therefore, in this embodiment, the guide groove 8 of the disc-shaped cam 7 that rotates in accordance with the elevation angle of the main reflecting mirror is set to a correction curve in accordance with the elastic displacement characteristic of the support column 1 in accordance with the elevation angle. The mirror axes of the reflecting mirror 3 and the main reflecting mirror can be made to coincide with each other at any elevation angle.

By setting the guide groove 8 of the disc-shaped cam 7 as a correction curve in accordance with the elastic deformation characteristics of the sub-reflecting mirror 3 and the supporting column 1 at the depression / elevation angle, the vertical direction of the sub-reflecting mirror 3 at any elevation angle. The movement can be corrected, and the correction can be continuously performed with respect to the elevation angle rotation of the antenna.

Also, by extending the guide groove 8, even when the elevation angle is lowered toward the reflection side beyond the depression angle direction or the zenith direction,
Similar correction is possible.

When the rotation range of the depression / elevation angle is narrow, the guide groove 8 may have a length corresponding to it, and a bearing for friction reduction may be used for the angular sliding portion, or a part of the large bevel gear may be thickened. It may be used as meat instead of the weight 11. Further, instead of directly fixing the guide pin 6 to the sub-reflecting mirror 3, the moving force by the guide groove 8 can be amplified and converted into the force for moving the sub-reflecting mirror 3 via the link mechanism.

(Effects of the Invention) As described above, according to the sub-reflector supporting device of the present invention, the sub-reflector is displaced due to its own weight without requiring a power source or an electric control circuit. It is possible to correct in a direction parallel to the base at any angle of depression and elevation, and it is possible to improve the characteristics of the antenna.

[Brief description of drawings]

FIG. 1 is a partially broken cross-sectional view showing a sub-reflecting mirror supporting device according to an embodiment of the present invention, and FIG. 2 is a plan view showing a disc-shaped cam of the sub-reflecting mirror supporting device of FIG. 1 ... Support pillar, 2 ... Base, 3 ... Sub-reflector, 4 ...
Guide hole, 5 ... Slider part, 6 ... Guide pin, 7 ...
… Disk cam, 8… Guide groove, 9… Small bevel gear, 10…
… Large bevel gear, 11 …… Weight, 12 …… Shaft support member, 13,1
6 ... axis, 14 ... arm, 15 ... pin.

Claims (1)

[Scope of utility model registration request] 1. A support column fixed to a main reflecting mirror, a sub-reflecting mirror for reflecting radio waves emitted from a radiator toward the main reflecting mirror, and a horizontal shaft fixed to the main reflecting mirror. A large bevel gear that is rotatably supported, a small bevel gear that meshes with the large bevel gear, and a disc-shaped cam that moves the shaft of the sub-reflecting mirror according to the rotation of the small bevel gear. Is provided on the support column, a shaft support member for rotatably supporting the shaft of the large bevel gear is provided at the base, and a weight is attached to the large cam gear at a position biased with respect to the shaft of the large cam gear. Is provided, the disc-shaped cam has a spiral guide groove, the guide pin is provided upright on the rear surface of the sub-reflecting mirror, and the guide pin is loosely inserted in the guide groove. Slide along the guide groove according to the rotation of the board cam. When the guide pin is moved and the guide pin slides along the guide groove, the base has a guide hole for sliding the sub-reflecting mirror in accordance with the movement of the guide pin, and the shaft of the small bevel gear. The sub-reflecting mirror support device is erected coaxially with the center of rotation of the disc-shaped cam.