JPH0393529A - Method and apparatus for molding flexible tube having ridge spirally provided to inside surface thereof in protruding state - Google Patents

Abstract

PURPOSE:To efficiently prepare a stable product generating no release at all by obstructing the hard resin of an inner layer subjected to co-extrusion in the extrusion molding stage of a tubular body to mold the same into a string state (ridge) and forming the string body into a spiral shape on the inside surface of an outer layer by the straightly advancing tubular body and the rotation of a barrier plate molding a string body to integrally weld the same. CONSTITUTION:The two-layer extrusion of an inside hard synthetic resin and an outside soft synthetic resin is performed by respectively supplying a hard synthetic resin (a) and a soft synthetic resin (b) to material supply ports 8, 9 and longitudinal yarn 23 is inserted in the intermediate part of the outside soft synthetic resin (b) to perform extrusion. Since a barrier plate 25 is rotated in the close contact state with the front end surface of the die of an extruder, the inside hard synthetic resin (a) in an extruded tubular body becomes a state possible to emit only in the notch part provided to the barrier plate 25 to be emitted and molded into to a string shape and, since the barrier plate 25 is rotated, the emitted and molded string is spirally provided to the inside surface of the straightly advancing tubular body. Since two notch parts are formed to the barrier plate 25, the two strings are emitted and two ridges are provided to the inside surface of the tubular body in a screw shape.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a flexible structure in which protrusions are spirally protruded on the inner surface of a wire protection tube, etc. used to protect cables such as M-wires and optical fibers. The present invention relates to a method for forming a flexible tube and a device for forming the same.

(Prior Art) A corrugated vipe is a commonly known synthetic resin pipe that has round or polygonal protrusions spirally arranged on its inner surface.

In this corrugated pipe, the cylindrical melt extruded from the double pipe land is expanded by compressed air jetted from the air hole, and the gold is sent by caterpillars circulating in front of the outside of the double pipe land. A corrugated pipe (fluted pipe) is continuously molded by crimping the corrugated part of the mold.

By the way, Kolgut pipes are made of synthetic resin such as polyethylene and vinyl chloride resin, and have uneven surfaces not only on the inside but also on the outside, and as a result, the pipe itself lacks pressure resistance.
The problem is that it is easily damaged by external pressure.

Therefore, in order to create a synthetic resin pipe with excellent pressure resistance and flexibility, we added reinforcement holes (projections) made of hard synthetic resin to the inner circumferential surface of the pipe.
It is conceivable to attach them in a spiral manner. This method involves integrally attaching reinforcing ridges made of hard synthetic resin to one side of a flexible tape-shaped soft resin band along its longitudinal direction.
IAW is applied, and such a soft resin band is wound spirally with the reinforcing protrusions placed on the inside, partially overlapping, and the overlapped parts are welded and integrated to form a pipe shape. It is.

Therefore, in this method, the band is first formed and then transferred to the next winding process and welded, which is time-consuming and difficult to control the dimensional accuracy of the completed tube. Moreover, since the pipe is formed by overlapping winding of a soft resin band, peeling of the overlap portion becomes a problem.

(Problems to be Solved by the Invention) In view of the above-mentioned conventional circumstances, the present invention has been developed in such a way that hard protrusions are already integrally formed in a spiral shape on the inner surface in the state of being extruded from an extrusion molding machine. The purpose is to write it as if it were written.

(Means for Solving the Problems) In order to solve the above problems, the molding method adopted by the present invention is to form a tubular shape by forming a hard synthetic resin layer on the inside and 8!1 soft synthetic resin layers on the outside. The inner hard synthetic resin layer in the extruded tubular material and the hard synthetic resin side of the soft synthetic resin layer bonded to it are separated by rotating a shielding plate having a notch at the extrusion port exit part to form a hard synthetic resin layer. A flexible tube is continuously formed by discharging a part of the synthetic resin layer and the soft synthetic resin layer in the form of a string from the notch, and integrating the melt into the inner surface of the outer soft synthetic resin layer in a spiral shape. It is characterized by

The laminated tube has blades not only in the resin layer but also in the outer soft synthetic resin layer constituting the tube body. A reinforcing material such as thread may be incorporated.

In addition, the hard synthetic resin protrusion welded and integrated with the inner surface of the soft synthetic resin layer is not limited to a single spiral shape, but may also be a multi-striped spiral shape. It is determined by the number of notches to be formed.

In addition, the molding device used to carry out the above-described molding method has a die front end surface of an extruder that extrudes and molds a tube with a laminated structure.
A disk-shaped shielding plate that closes the inner part of the outer diameter which is slightly larger than the discharge outer diameter of the inner diameter member of the die is rotatably supported in a close state, and the inner diameter of the discharge opening of the die is attached to the peripheral edge of the shielding plate. It is characterized by forming a notch cut to a position with a smaller diameter, and forcing the shielding plate to rotate freely.

The number of notches in the shielding plate may be one or more, and if there are more than one, the protrusions are formed in a multi-striped spiral.

(Operation) According to the above means, the hard synthetic resin and the soft layer that are laminated and extruded inside the soft synthetic resin of the outer layer constituting the tube body are blocked by the shielding plate having the cutout, and the The hard synthetic resin discharged from the notch is molded into a string shape, and the hard synthetic resin string (protrusion) is formed by the rotation of the straight-advancing tube body and the shielding plate.
is spirally attached to the inner surface of the soft synthetic resin layer, and is continuously molded integrally with the tube body.

(Effects of the Invention) Since the method for forming a flexible tube in which protrusions are spirally protruded from the inner surface of the present invention has the above-described structure, it is possible to The hard G3 resin of the extruded inner layer is molded into a string shape (protrusion), and this is formed into a spiral shape on the inner surface of the outer layer by the rotation of the straight tube and the shielding plate that forms the string. Can be formed by welding.

Therefore, compared to the conventional method of forming a flexible tube by spirally winding a tape-like material, since the tube is formed into a tube by extrusion molding from the beginning, there are problems such as peeling that were seen in the conventional method. There is no problem at all, and stable products can be produced efficiently. Moreover, by appropriately adjusting the extrusion speed and the speed of the rotating shielding plate, the pitch of the toraku can be easily changed and adjusted.

In addition, this molding device has a structure in which a shielding plate with a notch is forcibly rotated in close contact with the front end surface of the die of the extrusion molding machine, so it can be used for molding pipe bodies (hose). It can be easily manufactured by modifying the existing extrusion molding machine.

Also, if there is one notch in the shielding plate that rotates in front of the die, the protrusion will be one spiral, and if there are two, it will be two spirals, so it can be easily changed depending on the flexible tube to be obtained. can be changed to .

(Example) Embodiments of the present invention will be described below based on the drawings.

The drawing shows an extrusion molding machine that molds warp-filled pipes (tubes with warp threads) and is equipped with a shielding plate that forms part of the pipe material into a string and welds it to the inner surface of the pipe. Accurately align and fit the guide sleeve (A) 2 inside the fixed die head 1, fix it with the set bolt 3, and further insert the guide sleeve (B) 4 inside the guide sleeve (A) 2. Accurately align and fit together, fix with set bolts 5, and connect the inner peripheral surface of the fixed die head 1 and the guide sleeve (A
) 2 and between the inner circumferential surface of the guide sleeve (A) 2 and the outer circumferential surface of the guide sleeve (B) 4, through which the molten resin for molding the tubular body is guided and flowed. 7 is partitioned. Further, the fixed die head 1 is provided with a material supply port 8.9 that communicates with the passages 6 and 7 described above, and the material supply port 8, which communicates with the inner passage 6, is provided with a hard synthetic resin.
A soft synthetic resin is supplied to each of the material supply ports 9 communicating with the outer passage 7.

A thrust bearing 10, a bearing receiver 11, and a radial bearing 12 are installed inside the guide sleeve (8>4), and a shaft 13 is rotatably inserted inside the guide sleeve (8>4) and protrudes rearward from the rear end surface of the fixed die head 1. A nut 14 is screwed into the portion, and a sprocket 15 is fixed to a portion protruding rearward from the nut 14, and is driven and rotated by the power of a motor 16 or the like.

In addition, an inner die 1 is provided at the front end of the guide sleeve (B>4).
7 is the inner die 17 in the front part of the guide sleeve (A) 2.
Intermediate dies 18 are threadedly connected so as to cover the intermediate dies 18, and an outer die 19 is mounted on the outside of the intermediate dies 18, and is fastened and fixed with a bolt 21 via a die holder 20. The inner die 17 and the outer die 19 define a passage 22 in which the inner and outer resin materials are laminated, and the passage 22
Introducing passages 24 for warp threads 23 are formed.

Further, a connecting plate 25 is attached to a taper pin 26 at the tip of the shaft 13 that passes through the center hole of the inner die 17 and protrudes outside the die.
At the same time, the back surface of the shielding plate 25 is made into a flat surface and closely fitted to the end of the die.

The shielding plate 25 is shaped like a disk, and its outer diameter is equal to the passage 22.
The outer diameter of each layer is larger than the outer diameter of the laminated surface of the inner layer resin and the outer layer resin, and two notches 27. are formed on the periphery thereof. 2
7' is formed.

Said notch 27. 27' is a part where the inner layer resin is discharged in a string shape to form a protrusion, and there are two notches 27 on the circumference.
．． 27' allows two protrusions to be formed at the same time,
A double thread thread will be formed.

Further, the outer peripheral edge of the shielding plate 25 is tapered to ensure stable formation of the protrusions, and the central part is provided with an air outlet communicating with the air passage 28 formed on the outside of the shaft 13. 29 is formed, and the tubular body extruded from the die is expanded to a circular cross section by air pressure, so that the shape of the formed tubular body is maintained.

In the figure, 30 is a guide pipe for feeding air, 31 is a heater, and 32 is an air stopper.

In the device as described above, the hard synthetic wood 1 is connected to the material supply port 8.
By supplying 1ia and the soft synthetic resin b to the material supply port 9, a two-layer extrusion with a hard synthetic resin on the inside and a soft synthetic resin on the outside is performed, and the middle part of the outer soft synthetic resin b is Warp threads 23 are inserted and extruded.

Since the shielding plate 25 rotates in close contact with the front end surface of the die of the extruder, the hard synthetic resin a of the inner layer of the extruded tubular body is exposed to the notch 27 provided in the shielding plate 25,
Since the discharge is possible only at 27' and the mold is discharged in the form of a string, and since the "ixW&plate 25 rotates, the above-mentioned discharge molding in the form of a string is spirally attached to the inner surface of the tubular body that moves straight. Moreover, since there are two notches 27, 27' formed in the connecting plate 25, the string-like discharge becomes two threads, which are attached to the inner surface of the tubular body in the form of a two-thread thread.

A protrusion 34 attached to the inner surface of the tubular rest 33
The extrusion of the hard synthetic resin a of the inner layer extruded in a laminated state is passed through the connecting plate 25, and a part thereof is cut out in the notches 27, 2.
Since it is discharged from 7' to form the protrusions 34, the integrated structure with the soft synthetic resin b of the outer layer constituting the tube body 33 is very strong and stable.

In the above embodiment, the tubular body 33 has a single structure, but it is of course possible to have a laminated structure of two or three layers.

Further, the helical pitch of the protrusions 34 formed on the inner surface of the tubular body 33 depends on the extrusion molding speed of the tubular body 33 and the shielding plate 2.
By adjusting the rotation speed of 5, the pitch can be arbitrarily varied.

[Brief explanation of drawings]

The drawings show a tip embodiment of the present invention, and FIG. 1 is a w1 sectional front view;
Figure 2 is an enlarged sectional view of the main part, Figure 3 is (3)-
(3) It is a sectional view along the line. In the figure, 1 2, 4 17. 18, 19 27. 27' 34 Fixed die head guide sleeve die notch protrusion 25: Shielding plate 33: Tubular suspension Patent applicant TOYOX Co., Ltd.

Claims (2)

[Claims] (1) A hard synthetic resin layer is formed on the inside, a soft synthetic resin layer is laminated on the outside and extruded into a tubular shape, and the inner hard synthetic resin layer and the soft synthetic resin layer bonded to it are hard. The synthetic resin side is rotated at the outlet of the extrusion port, and a shielding plate having a notch is rotated to discharge part of the hard synthetic resin layer and the soft synthetic resin layer in a string shape from the notch. A method for forming a flexible tube having protrusions spirally protruding from an inner surface, characterized by continuously forming a flexible tube by integrally welding the inner surface in a spiral manner. (2) A disc-shaped shielding plate that closes the inner part of the outer diameter, which is slightly larger than the discharge outer diameter of the inner layer member in the die, is rotated in close contact with the front end of the die of the extruder that extrudes and molds the tube with a laminated structure. The inner surface is characterized in that a notch is formed in the peripheral edge of the shielding plate to a position smaller in diameter than the inner diameter of the discharge port of the die, and the shielding plate is forcibly rotatable. A device for forming flexible tubes with spirally protruding ridges.