JPS6128505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cylindrical body, and particularly to a method for manufacturing a flexible cylindrical body, such as a waveguide, using a thin metal tape.

Waveguides are widely used as microwave transmission lines in the UHF and SHF bands, and the manufacturing method explained in Figure 1 is considered as a manufacturing method for flexible waveguides using thin metal tape. It will be done. In FIG. 1, reference numeral 1 denotes a tape drum, in which a laminated tape 2 in which a thermoplastic resin is coated on one side of a thin metal tape serving as the material of the waveguide is wound. The laminated tape 2 is formed into a first cylindrical body 5 so that the thermoplastic resin layer is on the outside and both ends of the laminated tape 2 overlap each other. Subsequently, in the melt bonding device 6, the thermoplastic resin layers of the overlapped portions of the laminated tapes 2 are melted by a heating means 61 such as a hot jet to fuse the overlapped portions. At this time, as shown in FIG.
By introducing a metallic cylindrical forming tool 46 having an outer diameter that is approximately the same as the inner diameter of the cylindrical body and slightly smaller than the inner diameter of the cylindrical body, it is possible to apply sufficient pressure to the overlapped portion, and the melting process is performed. This not only ensures a perfect fit, but also prevents the cylindrical body from losing its shape. Incidentally, a release layer 45 made of Teflon or the like having a small coefficient of friction is applied to the entire surface of the cylindrical forming tool 46 to prevent scratches on the metal tape surface inside the cylindrical body 5 during manufacture of the cylindrical body. Vapor-deposited or attached. Next, in a molding device 7, the cylindrical body 5 is molded into a cylindrical body 8 having a desired shape, for example, a circular cylindrical body. Then, a protective coating such as polyethylene is applied on the 8 circumferences of the cylinder-shaped body using an extrusion device 9, and the thermoplastic synthetic resin layer of the laminated tape is fused to the protective coating by the heat during extrusion of the protective coating to make it thin. Adds mechanical strength to a cylindrical body made of metal tape. Next, the protective coating is cooled in the cooling device 13, and the waveguide 10 is manufactured. The waveguide 10 is taken up by a take-up device 11 and wound around a take-up drum 12, thereby continuously manufacturing the waveguide 10.

By the way, in the above-mentioned method, the laminated tape 2 is formed into a longitudinally continuous cylindrical body so as to wrap around a metal cylindrical forming tool provided with a release layer 46 such as Teflon over the entire surface, and then The overlapping parts of the laminated tapes are heat-sealed. When the release layer 46 of Teflon or the like is provided over the entire surface in this manner, the thermoplastic resin layer of the overlapping portion of the laminated tape 2 is melted by the hot jet 61 in the melt bonding device 6 and the overlapping portion is melted. When welding, the heat from the hot air from the hot jet outlet melts the release layer such as Teflon, exposing the metal part and causing scratches on the metal tape surface of the cylindrical body.
There are problems such as insufficient fusion of the overlapped parts, which causes peeling of the inner tape edges of the overlapped parts, and also problems such as the back tension due to friction, which causes thinning, etc., making it impossible to maintain the shape of the cylindrical body. arise. These scratches, peeling off of the tape edge, and irregularities in the shape of the cylindrical body should be avoided as much as possible since they deteriorate transmission characteristics such as increased attenuation when the cylindrical body is used as a waveguide.

The present invention has been made in view of the above-mentioned points, and it is possible to obtain a cylindrical body without scratches, with high dimensional accuracy, and with a desired cross-sectional shape, and which has good fusion bonding at the overlapped portion of the laminated tape. The present invention provides a method for manufacturing a cylindrical body that can obtain a cylindrical body, in which a laminated tape in which a thermoplastic synthetic resin layer is provided on at least one side of a metal tape is made into a cylindrical body in which at least the contact part with the laminated tape is made of a release material. In the method for manufacturing a cylindrical body, the cylindrical body is formed into a continuous cylindrical body in the longitudinal direction using a forming tool, and then the overlapped portions of the laminated tapes of the cylindrical body are heat-fused. The overlapping part of the laminated tape is heated at the intermediate position by a heating means, and then fused at the rear end. This is a method for manufacturing a cylindrical body, characterized in that:

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is an explanatory diagram of the manufacturing process of the present invention, and FIG. 4 is a cross-sectional view of the cylindrical forming tool of the present invention. In this figure, the same parts as in FIGS. 1 and 2 are given the same reference numerals.

In FIG. 3, reference numeral 1 denotes a tape drum around which a laminated tape 2, which is a material for a waveguide, is wound. The laminated tape 2 is a thin metal tape, such as a conductor tape made of a thin metal film such as aluminum or copper, and at least one side thereof is coated with a thermoplastic resin layer, such as a copolymer of ethylene and vinyl acetate. This laminated tape 2 is washed by a tape cleaning device 3, and then the laminated tape 2 is washed by a forming device 4.
is formed into a circular cross-sectional first cylindrical body 5 having an axis in the longitudinal direction so that the thermoplastic synthetic resin layer is on the outside, and in particular, both side edges of the laminated tape 2 are overlapped with each other. Subsequently, in the melt bonding device 6, the thermoplastic synthetic resin layers of the overlapped portions of the laminated tapes 2 are melted by heating means to completely fuse the overlapped portions. At this time, as shown in FIG. 4, at the positions of the molding device 4 and the melt bonding device 6, both ends 41 and 42 having an outer diameter that is approximately the same as the inner diameter of the first cylindrical body 5 but slightly smaller, and a A metal cylindrical molding tool 46 is disposed, which has a smaller intermediate portion 43 having an outer diameter smaller than the inner diameter of the cylindrical body 5, and has a gas flow hole 44 in the central portion in the longitudinal direction. Both ends 41 of the cylindrical forming tool 46,
On the outer surface of the tube 42, a release layer made of Teflon or the like having a small coefficient of friction is deposited or adhered to prevent scratches on the metal tape surface inside the tube during manufacture of the tube. The first cylindrical body 5 is formed by the forming device 4 so that the laminated tape 2 is wrapped around the surface of the large diameter portion 41 at one end of the cylindrical forming tool 46, and then by the melt bonding device 6.
At this point, the thermoplastic resin layer at the overlapping portion of the laminated tape 2 is melted by a heating means such as a hot jet 61 placed at the intermediate portion 43 of the cylindrical molding tool to fuse the overlapping portion. In this way, the cylindrical forming tool 46
The intermediate portion 43 has a smaller diameter than both end portions 41 and 42, and the intermediate portion 43 does not come into contact with the metal tape on the inner surface of the cylindrical body. Since heat fusion is performed at the intermediate portion 43, both ends 4 of the cylindrical forming tool 46
The release layer provided on the surfaces of Nos. 1 and 42 will not melt due to the heat during fusion and expose the metal part, so there will be no scratches on the metal tape surface of the cylindrical body, and the overlapped part will not be exposed. No peeling of the inner tape edge,
Further, the shape of the cylindrical body can be maintained.

Next, sufficient pressure is applied from the outside to the overlapping portion using the large diameter portion of the other end 42 of the cylindrical forming tool 46. Further, by allowing air to pass through the gas flow holes 44 of the cylindrical forming tool 46, the fused portion of the overlapping portion is cooled and the fusion is further completed, and a protective coating of polyethylene, which will be described later, is extruded and coated. By circulating air inside the cylindrical body, the rapid thermal contraction of the extruded protective coating that occurs when the extruded protective coating is cooled by the cooling device 13 is alleviated, and the shift and overlap of the edges of the laminated tape 2 at the overlapping part are prevented. It is also possible to prevent the peeling phenomenon of the inner tape edge of the mating part. Furthermore, by adjusting the pressure of the air passing through, internal pressure is applied to the cylindrical body after the protective coating has been extruded, thereby preventing flattening of the shape of the cylindrical body due to rapid cooling of the protective coating. Note that if an excessive amount of air is inserted at this time, the cylindrical body will become circular, so use a kettle and gauge for adjusting the amount of air to obtain the desired shape.

The cylindrical body 5 in which the overlapped parts thus formed are melt-bonded is then molded into a molding device 7 using a die or roll to form a cross-sectional shape with a long axis and a short axis, such as a rectangular, circular or similar circular cross-section. The second cylindrical body 8 is formed into a second cylindrical body 8. At this time, the forming device 7 is equipped with a mechanism that can rotate in the circumferential direction of the cylindrical body within a plane perpendicular to the direction of travel of the cylindrical body, and this mechanism allows the edge of the laminated tape located inside the laminated tape overlapping part to be rotated. The second cylindrical body 8 is molded by the molding device 7 so that it is located near the short axis in the cross section of the second cylindrical body 8 . In this way, the forming device 7 forms a cylindrical body having a cross-sectional shape with a long axis and a short axis, and the laminated tape edge located inside the laminated tape overlapping part is placed near the short axis in the cross section of the cylindrical body. When this cylindrical body is used as a waveguide, a thermoplastic synthetic resin layer is interposed between the metal tapes at the overlapping part, and even if the metal tapes are not in direct contact with each other, it can be used for a long time. When a fundamental mode is transmitted through a waveguide having a cross-sectional shape with an axis and a short axis, the current across the short axis is almost zero. The wall current that attempts to cross the edge of the metal tape perpendicularly is equal to zero, and there is no external radiation caused by the wall current that crosses the edge of the metal tape perpendicularly, creating a transmission line that functions as a waveguide. Next, on the second cylindrical body 8 formed by the molding device 7, a protective coating such as polyethylene is applied as an outer layer to a uniform thickness using an extrusion device 9, and the thermoplastic synthetic resin layer of the laminated tape is applied. The protective coating is fused with the heat during extrusion to give the thin metal tape mechanical strength, and then the protective coating is cooled in the cooling device 13 to form the waveguide 10.
Manufacture. The waveguide 10 is taken up by a take-up device 11 and wound around a take-up drum 12, thereby continuously manufacturing the waveguide 10.

As is clear from the above explanation, according to the present invention, the middle part of the cylindrical forming tool is made smaller in diameter than the inner diameter of the cylindrical body so as not to come into contact with the cylindrical body made of the laminated tape, and the position of this middle part is Since the overlapping portion of the laminated tape is heated by the heating means,
The release layer provided on the surface of both ends of the cylindrical molding tool will not melt due to the heat during heating and will not expose the metal part. Therefore, there will be no scratches on the metal tape surface due to melting of the release layer, or damage to the overlapping part. Peeling of the inner tape edge does not occur, the shape of the cylindrical body can be maintained, and a cylindrical body without scratches and having a desired cross-sectional shape with high dimensional accuracy can be obtained. In particular, even when a cylindrical body is used as a waveguide, a high-quality waveguide with excellent transmission characteristics can be obtained. In the embodiment, a Teflon release layer was deposited or adhered only to the surface of the large diameter portion of the cylindrical molding tool, but the entire large diameter portion or the entire cylindrical molding tool may be made of Teflon or wood. Alternatively, it may be a solid molding tool without gas flow holes.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the manufacturing process of a conventional cylindrical body;
The figure shows a cross-sectional view of a conventional cylindrical forming tool, FIG. 3 shows a manufacturing process explanatory diagram of the present invention, and FIG. 4 shows a cross-sectional view of a cylindrical forming tool of the present invention.

Claims (1)

[Claims] 1 A laminated tape having a thermoplastic synthetic resin layer on at least one side of the metal tape is formed into a longitudinally continuous cylindrical body so that at least the contact part with the laminated tape wraps around a cylindrical molding tool made of a release material. Next, in the method of manufacturing a cylindrical body, the overlapping portions of the laminated tapes of the cylindrical body are heat-sealed, and the forming tool has both ends having an outer diameter that is approximately the same as the inner diameter of the cylindrical body, and two ends having an outer diameter that is smaller than the inner diameter of the cylindrical body. 1. A method for producing a cylindrical body, the method comprising: heating an overlapping portion of the laminated tape at the intermediate portion using heating means; and then fusing the laminated tape at the rear end.