JPS62267Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Cassegrain type antenna, and more particularly to a supporting device part that can adjust the movement of a sub-reflector in the axial direction.

A Cassegrain antenna used for communication or various measurements in the microwave or millimeter wave band is basically constructed in the relationship shown in the side sectional view of FIG. That is, a primary radiator 2 located at the center of a main reflecting mirror 1 having a concave surface, and a sub-reflecting mirror having a convex surface facing these 1 and 2 are arranged in predetermined relationship positions, and from the primary radiator 2 A device that emits electromagnetic wave energy A and radiates it A', A' by a sub-reflector 3 and a main reflector 1 so as to have predetermined radiation characteristics is well known. This antenna can also reversibly converge and inject incoming radio waves into the primary radiator 2.

In the above antenna, the reference part for fixing it to the main part is usually the main reflector part, and with this as a reference, an appropriate frame etc. is provided, and the primary radiator and sub-reflector are arranged in the above-mentioned predetermined relationship. Fixedly placed so that What is particularly important in this case is the position and direction of the sub-reflector, and since it is located in space, it is difficult to maintain its position accurately.

Conventionally, as shown in the perspective view of the main part of FIG. 2, a rod-shaped shaft 6 coaxially protrudes from the back surface 5 opposite to the mirror surface 4 of the sub-reflector 20, and a support body 7 into which the shaft 6 is fitted;
The three plate-shaped attachment parts 8 that integrally protrude in the radial direction from the support body 7 and the supporting legs 9 that connect the attachment parts 8 and the main reflector part 1 (details not shown) are secured with screws 10. Was. Incidentally, numeral 11 is a screw screwed into the support body 7 for pressing and fixing the shaft 6. With the above configuration, with the screw 11 loosened, the shaft 6 is moved directly in the fitting direction of the support 7, that is, in the axial direction, and the distance position with respect to the primary radiator 2 and the main reflecting mirror 1 is adjusted. while fixing by tightening the screw 11.
On the other hand, attach the screws of the supporting leg 9 and the mounting part 8 to the sub-reflector 20.
Tighten and fix so that the axial direction of the main body matches the axial direction of the whole.

However, in the conventional sub-reflector mounting structure described above, the support leg 9 and the mounting portion 8 of the support body 7 are rotatable about the screw 10 in the direction of their mutual contact surfaces, and because of this rotatability, the axial direction is Although it is adjustable, since there is no part to serve as a reference, it is not only difficult to align the axial directions, but also there is a risk that it will still move even after being fixed. In addition, when the screw 11 is tightened with respect to the shaft 6, the screw 11 may tilt or move in the axial direction due to a gap in the fitting portion.

In view of the above-mentioned conventional problems, the purpose of the present invention is to provide an antenna in which a sub-reflector can be mounted extremely stably and reliably.For this purpose, the present invention has developed a sub-reflector that is supported by at least three supporting legs from the main reflector. a reflecting mirror support device, the supporting device having a screw hole in the center thereof into which a screw shaft is screwed into a recess into which a guide portion having a circular cross section that projects integrally and coaxially from the opposite back side of the mirror surface of the reflecting mirror is fitted; It has a hole in which the end of the support leg is fitted and fixed in a straight line, and a lock nut is provided on the screw shaft, and by screwing and rotating the sub-reflector screw shaft, the sub-reflector surface is axially aligned with respect to the main reflector. The distance can be adjusted and locked in any direction. With such a configuration, the distance adjustment in the axial direction can be performed stably. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a schematic side view of an antenna according to an embodiment of the present invention, and FIG. 4 shows a cross-sectional view of the sub-reflector attachment part. In the figure, a main reflecting mirror 1 has a mounting frame 1' integrally formed on its back surface, and a sub-reflecting mirror 20 is disposed at a predetermined position facing a concave surface (rotating rod surface). This sub-reflector 20 has a back surface 2 opposite to the mirror surface.
A guide portion 22 having a circular cross section and a threaded shaft 23 are provided on one side and integrally protrude coaxially, and a groove 24 is formed at the end of the threaded shaft 23. On the back side 21 of the sub-reflector 20, a recess 25 having a substantially trapezoidal side cross section and into which the guide portion 22 fits is formed in the center of one end, and a screw hole 26 penetrating the other end in the bottom of the recess 25. The sub-reflector support device 30 has three holes 27 in the figure (however, only two are shown in the figure) perpendicular to the surrounding trapezoidal surface for fitting the supporting leg ends, which will be described later. A mirror 20 is screwed together. One end of the three supporting legs 40 is stepped, and the narrow diameter portion 41 of the three supporting legs 40 is fitted into the hole 27 and fixed by a screw 42 inserted from the slope of the recessed portion of the other end of the supporting device. This supporting leg 40 is fitted at right angles to the substantially trapezoidal slope of the supporting device 30, so that it is mounted accurately, firmly and stably. The other end 43 is attached to the surface of the main reflecting mirror 1 with a screw 44. Note that 45 is a lock nut. The main reflecting mirror is manufactured by a well-known sheet metal drawing process and is connected to the mounting frame 1' by means such as welding.

With the above configuration, when a suitable tool such as a screwdriver is applied to the groove 24 and rotated in either direction of the arrow B, the screw shaft 23 screwed into the screw hole 26 rotates.
Along with this, the integral sub-reflector 20 moves in the axial direction while rotating. At this time, the guide portion 22 fits into the recess 25 and in the fitted state provides accurate guidance and support in the axial direction, so that the axis of the sub-reflector is maintained so as to be extremely unlikely to tilt. Further, when the sub-reflector position reaches a predetermined position, the lock nut 45 is tightened to lock the screw shaft 23. In addition, in the above configuration, the support leg 4
The fitting between the threaded part 23 and the guide part 22 is sufficiently ensured so that the position of the sub-reflector 20 as a whole including zero can be moved at least within a range that includes errors and requires adjustment.

As mentioned above, according to the present invention, the integrated support device guides and supports the sub-reflector with extremely high precision, and since the supporting legs are fitted in a straight line, the axial direction of the sub-reflector can be accurately aligned with respect to the main reflector. It has been confirmed that it can be manufactured with virtually no errors and that virtually no angle adjustment is required. Therefore, in order to efficiently set the predetermined distance intervals, as shown in FIG. A vertex plate (top alignment plate) 28 whose bottom surface of the recessed hole 54 in the tip portion 52 is formed in the center of the sub-reflector 20.
This can be done with high efficiency by adjusting the above operation so that it is in contact with the surface. Of course, it goes without saying that the length between the attachment flange surface 53 of the jig 50 and the bottom surface of the recessed hole 54 of the tip 52 is determined to be a predetermined distance. It is also possible to check and correct the eccentricity based on the fit between the outer diameter of the plate 28 and the recessed hole 54. After the adjustment and fixing of the position is completed, the jig 50 is removed and the primary radiator is attached to the main part of the attachment device in a predetermined position.

As described above, the present invention is relatively small and fixed.
It has shown excellent effects when applied to portable antennas and even to antennas mounted on vehicles.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the basic configuration of a Cassegrain antenna, Fig. 2 is a conventional sub-reflector mounting structure, Fig. 3 is a schematic side view of an embodiment of the antenna of the present invention, and Fig. 4 is the sub-reflector mounting section. FIG. 5 is an explanatory diagram of an adjustment method using a jig. In the figure, 1 is a main reflector, 2 is a primary radiator, 20 is a sub-reflector, 30 is a support device, 40 is a supporting leg, and 50 is a jig.

Claims (1)

[Scope of utility model registration request] A sub-reflector support device supported by at least three supporting legs from the main reflector part, and a guide portion having a circular cross section that protrudes integrally and coaxially from the back side opposite to the sub-reflector surface is fitted in the center of the support device. The screw shaft is provided with a recess and a screw hole into which the screw shaft is screwed, and a hole around the periphery into which the end of the support leg is fitted and fixed in a straight line, and a lock nut is provided on the screw shaft, and the screw shaft is screwed into the screw shaft. A Cassegrain antenna whose distance can be adjusted and locked in the axial direction of the sub-reflector surface with respect to the main reflector by screwing and rotating the shaft.