JPH02291703A - Radar dome made of fiber reinforced plastic - Google Patents

Abstract

PURPOSE:To omit the seams and the overlapping parts and to prevent the local change of an electric constant by using an elastic multi-layer fabric where the warps forming many layers cross the yarns of other layers which are woven into the warp layers every second one and are adjacent to each other every plural pieces of yarn. CONSTITUTION:A multi-layer fabric 2 forms the inner side of a radar dome 1 with lamination of the impregnated epoxy resin, etc. A rubber cap 3 covers the outer circumference surface of the fabric 2, and a plastic film 4 covers the outer circumference of the cap 3. The fabric 2 contains the wafts x1, x2... and the warps y1, y2..., and the wefts x1, x2... are woven into the layers (a, c...) of warps every second one and sometimes cross the yarns of other layers (b...) adjacent to each other. As a result, the dome 1 is free from any cut part and overlapping part of the fabric 2 and therefore excels in the electrical characteristic and the structural strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fiber-reinforced plastic radar dome mounted on an aircraft or the like.

[Conventional technology]

As shown in Figure 5, the conventional radar dome attached to the tip of an aircraft has a hemispherical tip that tapers toward the rear, and a receiver is installed inside. 02 is installed.

Due to the required electrical performance, the radar dome 01 has a laminated structure or a sandwich structure made of a composite material reinforced with glass fiber, silica fiber, etc., and is widely used.

The manufacturing method of the above-mentioned radar dome Ol is explained with reference to FIG. 6. The manufacturing method is as follows: epoxy resin is applied to a fabric such as glass fiber. A thermosetting resin such as polyester resin is impregnated to form a molding material 03 (hereinafter referred to as prepreg), which is then molded into a mold 040 while making cuts 05 to prevent wrinkles or folded portions from forming in the prepreg 03. After carefully laminating the layers on the surface to a desired thickness, they were covered with plastic film 06 and molded using a pressure heating device such as an autoclave.

[Problem to be solved by the invention]

In conventional radar domes, the prepreg does not expand or contract very much, so it was necessary to cut the prepreg and match or overlap the cut surfaces to form a mold. For this reason, local changes in the plate thickness and electric constants of the material at these locations adversely affect the radio wave performance of the radar dome. Furthermore, since there were cut portions of fibers in the product, it was also disadvantageous in terms of strength.

The present invention has been made in view of such circumstances, and
The present invention aims to manufacture a radar dome without having cut portions of fabric in the molded product, and to provide a radar dome with good mechanical strength and radio wave performance.

[Means to solve the problem]

The radome of the present invention is made of epoxy resin consisting of multi-layered warp threads and weft threads that are mainly woven into each layer of the warp threads and intersect with threads of other layers adjacent to the warp threads at a rate of one warp thread for every plurality of warp threads. It is characterized by being made of a stretchable multilayer fabric impregnated with

[Effect]

In the above, the multilayer fabric is impregnated with epoxy resin etc.
After being laminated on the surface of a molding jig, the resin is heated under pressure using an autoclave or the like to harden and form a radar dome.

The multilayer fabric has weft yarns woven every other layer, has a weak bond with the intermediate layer, and is stretchable, so it fits well on the surface of the molding jig and can be brought into close contact with the molding jig without making cuts.

As a result of the above, the radar dome is created without the abutting or overlapping parts of the cut surfaces of the fabric, making it possible to prevent local changes in the electrical constant that occur at the relevant parts, improving the radio wave performance of the radar dome as well as its mechanical strength. I was able to figure it out.

〔Example〕

An embodiment of the present invention is shown in FIG.

The present embodiment shown in FIG. 1 includes a multilayer fabric 2 impregnated with epoxy resin and laminated to form the inside of a radar dome 1;
A rubber cap 3 provided on the outer peripheral surface of the multilayer fabric 2
, and a plastic film 4 provided on the outer peripheral surface of the cassop 3.

In the above, the multi-lm snout 2 has the weft xI + x2 * . . . and the warp YI. Yt
It's more like... Warp above)'l. )'
2, . . . are the a-a cross section and the bb-b cross section in Fig. 2. ...Figure 3 (al. (b)) showing the cross section of the group
, −・・・・・・, As shown in (/), multi-Fi(am
, b layer, (1, old...), weft xI +
X2 +... is woven into each warp layer (layer a, layer C...), and is sometimes woven into each other layer (layer b,...) of the adjacent layer. ...) thread.

To mold the radar dome 1 using the multilayer fabric 2, first, the multilayer fabric 2 impregnated with epoxy resin or the like is laminated on the surface of a molding jig 5 that has been subjected to an appropriate mold release treatment. The multilayer fabric 2 has good compatibility with the molding jig 5 because the weft yarns are woven every other layer and the intermediate layer has a weak bond and expands and contracts.
It can be brought into close contact with the molding jig 5 without making cuts. After laminating the multilayer fabric 2, in order to obtain surface smoothness, a Laher cassob 3 in the shape of a radar dome 1 is placed over the laminated surface, and the surface is further covered with a plastic film 4. The resin is hardened by pressure heating using a pressure heating device such as a crepe to form the radome 1.

As a result of the above, the radar dome does not have any cutting or overlapping parts of the fabric, so it is electrically sensitive. A radar dome with excellent strength and a smooth surface and good appearance was obtained.

Another example of the radar dome using the above multilayer fabric is shown in the fourth example.
As shown in the figure.

In the present embodiment shown in FIG. 4, the outer skin 7 and the inner skin 8 are formed of the multilayer fabric impregnated with epoxy resin and laminated, and between the outer skin 7 and the inner skin 8 there is a core 9 at -i. The radar dome has a so-called sand-inch structure. This radar dome can also be manufactured in the same manner as the above embodiment shown in FIG. 1, and has the same effects.

〔Effect of the invention〕

The radome of the present invention is made of a stretchable multilayer fabric, which is mainly woven into each layer of warp threads forming a multilayer structure, and intersects threads of other layers adjacent to each other at a ratio of one warp thread in each plurality of warp threads. By using a radar dome, there are no seams or overlapping parts of the fabric, so local changes in the electrical constant that occur in the area can be prevented, improving radio wave performance.Furthermore, since there are no seams, mechanical strength can be improved. We were also able to improve this.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of a multilayer fabric used in the above embodiment, Fig. 3 is a sectional view of the multilayer fabric used in the above embodiment, and Fig. 4 is an explanatory diagram of the multilayer fabric used in the above embodiment. FIG. 5 is an explanatory diagram of another embodiment of the present invention, FIG. 5 is an explanatory diagram of a conventional device, and FIG. 6 is an explanatory diagram of a conventional method of manufacturing the device. 1... Radar dome, 2... Multilayer fabric, 3...
Rubber camp, 4... Plastic film, 5... Molding jig, 7... Outer skin, 8...
Inner skin, 9...core.

Claims (1)

[Claims] It is made up of multi-layered warp threads and weft threads that are woven into each of the warp threads every other layer and intersect with the threads of other layers adjacent to the warp threads at a ratio of one warp thread to every other warp thread.It is impregnated with an epoxy resin and has elasticity. 1. A fiber-reinforced plastic radome characterized by being made of a multi-layered fabric.