JPS59132207A - Manufacture of rectangular waveguide - Google Patents

Abstract

PURPOSE:To attain remarkable man-hour reduction and cost reduction by forming an ''Invar'' flat bar into round shape, forming a round pipe by seam welding and drawing this round pipe so as to form a rectangular waveguide. CONSTITUTION:First the ''Invar'' flat bar 1 is formed into round shape, the seams 3 are welded to form the ''Invar'' welded round pipe 2. Then, the pipe end of the round pipe 2 is squeezed by a hydraulic press so as to form the pipe end of the round pipe 2 into a flat trigger. Then, the flat trigger is passed into a roller die of parallel rolls and the trigger is drawn by a chain type drawing machine. In taking the pitch of the parallel rolls as a larger size than a short side of the final rectangular shape slightly in this case, an intermediate square pipe 4 having a slightly larger diameter than that of the final rectangular pipe is formed. The residual stress is eliminated by applying heat treatment to the intermediate square pipe 4, a lubricant is coated, then drawing is executed by a conventional drawing machine. Thus, the ''Invar'' rectangular waveguide 5 is obtained. Remarkable man-hour and cost reduction are attained by this method.

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention relates to a method for manufacturing a rectangular waveguide, and particularly to a method for manufacturing a rectangular waveguide, and in particular, a method for manufacturing a bandpass filter (Band Pa5sF) of a multiplex radio device.
The present invention relates to a method of manufacturing an Invar rectangular waveguide used in ilter (hereinafter simply abbreviated as rBPF J) and the like.

(2) Background of the technology Copper, aluminum, or alloys thereof are generally used as materials for waveguides. Further, depending on the application, for example, for waveguides for BPF which require frequency stability, invar, which has a small linear expansion coefficient and excellent temperature characteristics, is used.

However, in the manufacture of Invar rectangular waveguides, the amount used (production amount) is small, and because they are made of special materials, the same methods as those for conventional copper-based or aluminum-based rectangular waveguides cannot be applied.

(3) Conventional technology and problems The conventional manufacturing method of copper-based or aluminum rectangular waveguides is as follows:
It is formed into a rectangular tube by drawing.

However, in the case of Invar, an Invar round tube with a wall thickness much thicker than the required value is formed by extrusion, and this round tube is formed into a predetermined uniform thickness by cutting and drawing. However, since the method of forming the waveguide into a rectangular waveguide is adopted, the drawing process is extremely large, and the large number of drawing processes means that heat treatment, cleaning,
It is necessary to repeat processes such as tin removal, and therefore there are problems in that productivity is very low and manufacturing costs are extremely high.

(4) Object of the Invention In view of the above-mentioned prior art, it is an object of the present invention to provide a new method that can manufacture an Invar rectangular waveguide with fewer man-hours and at low cost.

(5) Structure of the Invention The present invention generally focuses on the fact that an Invar flat plate can be formed to have any uniform thickness, and manufactures a rectangular waveguide from an Invar flat plate.

That is, the method for manufacturing a rectangular Invar waveguide according to the present invention involves forming a flat Invar plate into a round shape, welding the seams to form a round tube, and then drawing the round tube to form a rectangular waveguide. It is something to be molded.

According to this method, the number of man-hours and costs can be significantly reduced by i=J compared to the case of manufacturing from conventional thick-walled round tubes.

(6) Embodiments of the invention Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.

The figure shows the manufacturing process of the Invar rectangular waveguide of the present invention (a) First, a flat Invar plate 1 having a predetermined thickness necessary to obtain the final thickness of the waveguide is marked with a circle indicated by 2. mold into shape,
The seam 3 is welded by MIG or TIG welding to form the invar-welded round tube 2. And this round tube 2
In order to make the bead portion 3 uniform, it is finished into a round tube of predetermined dimensions using a conventional chain-type drawing machine, and then heat-treated to obtain a standard structure.

(b) Next, crush the end of the round tube 2 with a hydraulic press so that it becomes a flat puller. At this time, the bead portion 3 is positioned at an appropriate position based on various conditions such as the characteristics of the waveguide, strain stress, and the position of the pin to be brazed into the waveguide. In the illustrated example, the bead portion 3 is located at the center of the short side of the rectangle, but it is of course possible to position it on the long side.

(c) Then, pass the above flat puller through a roller die of parallel rolls and pull it out with a puller chain type puller. At this time, by making the interval between the parallel rolls slightly wider than the short sides of the final rectangular shape, an intermediate rectangular tube 4 having a diameter larger than that of the final rectangular tube is formed.

2) After heat-treating the intermediate square tube 4 to remove residual stress and applying a lubricant, it is precisely finished and drawn using a regular drawing machine using a die with a rectangular doll and a rectangular mandrel. conduct.

(e) According to the above, the dimensional tolerance of both the inner and outer diameters of the long side and short side of the rectangle is within 1 Qyis, and the inner corner radius is 1.
An invar rectangular waveguide 5 having a dimensional accuracy of within 0.00 m is obtained.

Incidentally, specific process examples of the method of the present invention are shown in Table 1. Incidentally, the conventional method for manufacturing thick-walled invar round tubes requires approximately twice the number of steps shown in Table 1.

Margin table below - 1 1. Material (Invar flat plate) 2. Raw pipe (seam welded) 3. Tip 4. Pickling 5. Internal brushing 6. Pickling, water washing 7, 7 Elbond 8. Bonida Lube (drying) 9 , Expansion pipe IOL degreasing (orun) 11, pickling, water washing 12, annealing 13, pickling 14, inner surface brushing 15, roll corner forming 16, #blunt 17, pickling 18, brushing 19, pickling, water washing 20 , reactor troupe 21 square elongated pipe 22, manual correction 23, inner surface cleaning 24, inspection (7) Effects of the invention As described above, according to the present invention, the invar rectangular waveguide i4
- It can be manufactured with a small number of man-hours and at low cost, and its economic effect is significant.

[Brief explanation of drawings]

The figure is a schematic process diagram of an embodiment of the method for manufacturing an invar rectangular waveguide according to the present invention. l... Invar flat plate, 2... Welded round tube, 3...
Seam (peed part), 4... intermediate square tube, 5... invar rectangular waveguide. Patent Applicant Fujitsu Limited Tsurumi Kokan Co., Ltd. Patent Application Representative Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate 1) Yukio Patent Attorney Akira Yamaguchi 1538-6 Kamoi-cho, Midori-ku, Yokohama City 0 Applicants Tsurumi Steel Tube Co., Ltd. 1-4-30 Yako, Tsurumi-ku, Yokohama

Claims (1)

[Claims] 1. In the method of manufacturing a rectangular waveguide of Invar, a flat plate of Invar is formed into a round shape, the seams are welded to form a round tube, and the round tube is drawn and formed into a rectangular waveguide. A method for manufacturing a rectangular waveguide, characterized by: